Randomized, Placebo-controlled Parallel Group Clinical Trial of Nicotinamide Riboside to Evaluate NAD+ Levels in Individuals With Persistent Cognitive and Physical Symptoms After COVID-19 Illness ("Long-COVID")
Phase: PHASE4
Conditions: Covid19, Sequelae of; Infection, Cognitive Symptom
Sponsor: Massachusetts General Hospital

 
Randomized, Placebo-Controlled Parallel Group Clinical Trial of Nicotinamide Riboside to evaluate NAD+ Levels in Individuals with Persistent Cognitive and 
Physical Symptoms After COVID19 Illness ("Long-COVID") 
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Version date: December 9, 2024 
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Randomized, Placebo-Controlled Parallel Group Clinical Trial of Nicotinamide Riboside to evaluate NAD+ Levels 
in Individuals with Persistent Cognitive and Physical Symptoms After COVID19 Illness ("Long-COVID") 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Edmarie Guzmán-Vélez, PhD 
Principal Investigator 
Massachusetts General Hospital 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Protocol Number: 2021P000158 
NCT04809974 
Version Number/Date: 1.1/ December 9, 2024 
 
 
The information contained herein is confidential and proprietary in nature and will not be disclosed to any third party without 
written approval of authorized designee. This document may be disclosed to the appropriate institutional review boards or 
to duly authorized representatives of the US Food and Drug Administration or national regulatory authority under the 
condition that they maintain confidentiality.  

 
Randomized, Placebo-Controlled Parallel Group Clinical Trial of Nicotinamide Riboside to evaluate NAD+ Levels in Individuals with Persistent Cognitive and 
Physical Symptoms After COVID19 Illness ("Long-COVID") 
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STATEMENT OF COMPLIANCE 
 
This study will be conducted in compliance with the protocol, International Conference on Harmonisation of Technical 
Requirements for Registration of Pharmaceuticals for Human Use (ICH), Good Clinical Practice (GCP), and the applicable 
regulatory requirements, United States Code of Federal Regulations (CFR) Title 45 CFR Part 46 and Title 21 CFR Parts 50, 
56, and 312. 
 
 

 
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Table of Contents 
STATEMENT OF COMPLIANCE ..................................................................................................................................... 2 
LIST OF ABBREVIATIONS ............................................................................................................................................... 6 
1. 
ETHICS/PROTECTION OF HUMAN SUBJECTS ................................................................................................ 8 
1.1  INSTITUTIONAL REVIEW BOARD (IRB) ............................................................................................................... 8 
1.2  ETHICAL CONDUCT OF STUDY .............................................................................................................................. 8 
1.3  SUBJECT INFORMATION AND CONSENT ............................................................................................................. 8 
2. 
INTRODUCTION: BACKGROUND INFORMATION AND SCIENTIFIC RATIONALE .............................. 9 
2.1 BACKGROUND INFORMATION .................................................................................................................................. 9 
2.1.1  SARS-CoV-2 infection .................................................................................................................................. 9 
2.1.2  Nicotinamide Riboside Rationale .................................................................................................................. 9 
2.1.3 Nicotinamide Riboside and SARS-CoV-2 ................................................................................................... 10 
Figure 2. Kaplan-Meier curve for all 93 participants enrolled in the clinical trial that tested a combined 
metabolic cofactor supplementation in individuals infected with COVID-19. ........................................... 10 
2.1.5  Prior Clinical Use of Nicotinamide Riboside .............................................................................................. 11 
3. 
SPECIFIC AIMS........................................................................................................................................................ 11 
3.1 
OVERALL STUDY DESIGN AND PLAN ................................................................................................................ 11 
3.2 
STUDY OBJECTIVES ................................................................................................................................................ 12 
3.2.1 Standardized Cognitive, Functional, and Neuropsychiatric Outcome Measures ........................................ 12 
3.3  PROTOCOL ADHERENCE ....................................................................................................................................... 13 
4.  
SUBJECT SELECTION ........................................................................................................................................... 13 
4.1 
INCLUSION AND EXCLUSION CRITERIA ........................................................................................................... 13 
4.1.1  Inclusion Criteria ......................................................................................................................................... 13 
4.1.2  Exclusion Criteria ........................................................................................................................................ 14 
4.1.2.1 INDIVIDUALS OF CHILDBEARING AGE ........................................................................................................... 16 
4.2 RECRUITMENT ............................................................................................................................................................. 16 
4.2.1 Recruitment of Subjects through Advertising .............................................................................................. 16 
4.2.2 Recruitment of Subjects Identified through Private Medical Information .................................................. 16 
4.2.3 
Recruitment of Subjects from the MGH McCance Center for Brain Health .............................................. 17 
4.2.4 Recruitment of Subjects from Among the Investigators’ Own Patients...................................................... 17 
5.  
SUBJECT ENROLLMENT ...................................................................................................................................... 17 
5.1 
INFORMED CONSENT PROCESS ........................................................................................................................... 17 
5.2  REMUNERATION ...................................................................................................................................................... 18 
5.3 
RANDOMIZATION .................................................................................................................................................... 19 
5.4 
REASONS FOR WITHDRAWAL .............................................................................................................................. 19 
5.4.1  Handling of Withdrawals ............................................................................................................................. 19 
5.5  TERMINATION OF STUDY ..................................................................................................................................... 19 

 
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6. 
STUDY PROCEURES .............................................................................................................................................. 21 
6.1 
 SCHEDULE OF ASSESSMENTS FOR THE CLINICAL TRIAL ........................................................................... 21 
6.2 
 SCHEDULE OF ASSESSMENTS FOR THE ONE-TIME VISITS ......................................................................... 22 
6.2.1 SCREENING/LEAD-IN VISIT (WEEK 0) ................................................................................................................ 25 
6.2.1.1 
Screen Failures ........................................................................................................................................... 25 
6.2.2 Baseline Visit (Week 2) ............................................................................................................................... 25 
6.2.3    Follow Up Visits (Weeks 7, 12 and 17) .................................................................................................... 25 
6.2.4 Final study visit ........................................................................................................................................... 26 
6.2.5 Early Termination Visit ............................................................................................................................... 26 
6.2.8  PROTOCOL DEVIATIONS ...................................................................................................................................... 27 
6.2.9 MISSED VISITS AND PROCEDURES ..................................................................................................................... 27 
7 
CLINICAL ASSESSMENTS AND OUTCOME MEASURES ............................................................................. 27 
7.1 
CLINICAL VARIABLES............................................................................................................................................ 28 
7.1.1  Safety Measures ........................................................................................................................................... 28 
7.1.1.1 Vital Signs, Height, Weight ........................................................................................................................... 28 
7.1.1.2 
Clinical Laboratory Assessments............................................................................................................... 28 
7.1.1.3 Adverse Events .............................................................................................................................................. 28 
7.1.2 Clinical Assessments .................................................................................................................................... 28 
7.1.2.1 Neuropsychiatric and Functional Assessments.............................................................................................. 28 
7.1.2.1.5  Pittsburgh Sleep Quality Index .................................................................................................................. 29 
7.1.2.1.6  International Physical Activity Questionnaire (IPAQ) .............................................................................. 29 
7.1.2.2 Neurocognitive Assessments ......................................................................................................................... 29 
7.1.1.3.1 Physical and Neurological Examination ..................................................................................................... 30 
7.1.2.4   Phlebotomy and collection of dried blood spot samples for Biomarkers .................................................... 30 
7.1.2.5 
 Magnetic Resonance Imaging (MRI) ....................................................................................................... 31 
7.1.3 Daily Outcomes ........................................................................................................................................... 31 
7.1.3.1 
 Daily activity and sleep tracking .............................................................................................................. 31 
7.2  TRAINING AND VALIDATION.................................................................................................................................. 32 
8.  
INTERVENTIONS ADMINISTERED.................................................................................................................... 32 
8.1  INTERVENTION ........................................................................................................................................................ 32 
8.1.1  Study Product Description ........................................................................................................................... 32 
8.1.2  Drug and Placebo ......................................................................................................................................... 32 
8.1.3  ACQUISITION ............................................................................................................................................................ 33 
8.2.  Product Storage and Stability ...................................................................................................................... 33 
8.3 
DOSAGE, PREPARATION AND ADMINISTRATION OF STUDY INTERVENTION........................................ 33 
8.4 
MODIFICATION OF STUDY INTERVENTION FOR A SUBJECT ....................................................................... 33 
8.4.1  Dosage Discontinuation ............................................................................................................................... 33 
8.5  ASSESSMENT OF SUBJECT COMPLIANCE ......................................................................................................... 33 
9. 
STATISTICAL ANALYSIS...................................................................................................................................... 33 

 
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9.1  SAMPLE SIZE DETERMINATION ....................................................................................................................... 33 
10. 
SAFETY AND ADVERSE EVENTS ....................................................................................................................... 34 
10.1  POTENTIAL RISKS AND BENEFITS ...................................................................................................................... 34 
10.1.1  
Potential Risks ....................................................................................................................................... 34 
10.1.2  
Known Potential Benefits ...................................................................................................................... 36 
10.2.2 MOBILE DEVICE ..................................................................................................................................................... 36 
10.2.3 
Fitbit activity tracker .............................................................................................................................. 36 
11. 
MONITORING AND QUALITY ASSURANCE ................................................................................................... 36 
11.1  Independent Monitoring of Source Data ..................................................................................................... 37 
11.2  Safety Monitoring ........................................................................................................................................ 37 
11.3  DEFINITIONS OF AES & SAES ............................................................................................................................... 37 
11.3.1  
Adverse Event ........................................................................................................................................ 37 
11.3.2  
Serious Adverse Events ......................................................................................................................... 38 
11.4  ASSESSMENT AND RECORDING OF ADVERSE EVENTS ................................................................................ 39 
11.4.1 
Assessment of Adverse Events .............................................................................................................. 39 
11.4.2  
Relatedness of Adverse Event to Investigational Protocol .................................................................... 39 
11.4.3  
Recording of Adverse Events ................................................................................................................ 40 
11.5  ADVERSE EVENTS AND SERIOUS ADVERSE EVENTS - REPORTABLE EVENTS ...................................... 40 
11.6  SAFETY AND FEASIBILITY OF PERFORMING EXPERIMENTAL VISITS AT MGH-EAST 
(CHARLESTOWN NAVY YARD) ...................................................................................................................................... 40 
12.  BIBLIOGRAPHY ...................................................................................................................................................... 41 
 
 
 

 
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LIST OF ABBREVIATIONS  
 
 
 
AD 
 
Alzheimer’s Disease 
AE 
 
Adverse Event/Adverse Experience  
ASL 
 
Arterial Spin Labeling 
BAI 
 
Beck Anxiety Inventory 
BDI 
 
Beck Depression Inventory 
BOLD  
Blood Oxygen Level Dependent 
BRIEF-A 
Behavioral Rating Inventory of Executive Function – Adult Version 
CBC  
Complete Blood Count 
CFR   
Code of Federal Regulations  
CRF 
 
Case Report Form 
CNS 
 
Central Nervous System 
CNY  
Charlestown Navy Yard  
Co-I 
 
Co-Investigator  
COVID19 
Coronavirus SARS-CoV-2 
CPT 
 
Continuous Performance Test  
CSF   
Cerebrospinal Fluid  
DKEFS 
Delis-Kaplan Executive Function System 
DNA   
Deoxyribonucleic acid  
DOB  
Date of Birth 
eCOG  
Everyday Cognition Scale 
eCRF   
Electronic Case Report Form  
EDC   
Electronic Data Capture  
FABP  
Fatty Acid Binding Protein 
FDA  
Food and Drug Administration  
GCP   
Good Clinical Practice  
GFAP  
Glial Fibrillary Acidic Protein 
GRAS  
Generally Recognized as Safe  
HC 
 
Healthy Control 
HIPAA  
Health Insurance Portability and Accountability Act  
HRC  
Human Research Committee  
ICF  
 
Informed Consent Form  
ICH   
International Conference on Harmonisation  
IPAQ  
International Physical Activity Questionnaire 
IRB 
 
Institutional Review Board 
MCI 
 
Mild Cognitive Impairment 
MDU  
Memory Disorders Unit 
MGH   
Massachusetts General Hospital  
MRI 
 
Magnetic Resonance Imaging 
MRN  
Medical Record Number 
NAB  
Neuropsychological Assessment Battery 
N  
 
Number (typically refers to subjects)  
NAD+  
Nicotinamide Adenine Dinucleotide  
NFL   
Neurofilament light-chain protein 
NMN  
Nicotinamide mononucleotide 

 
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NR 
 
Nicotinamide riboside 
PBO 
 
Placebo 
pCASL 
Pulsed Continuous Arterial Spin Labeling  
PCL-C  
Post Traumatic Stress Disorder Checklist – Civilian 
PHRC  
Partners Human Research Committee 
PI  
 
Principal Investigator  
PT/INR 
Prothrombin Time and International Normalized Ratio  
RBANS 
Repeatable Battery for the Assessment of Neuropsychological Status 
rsBOLD 
Resting State Blood Oxygen Level Dependent 
rsfMRI 
Resting State Functional Magnetic Resonance Imaging  
SAE   
Serious Adverse Event  
SCD 
 
Subjective Cognitive Decline 
TMT  
Trail-Making Test 
TOPF  
Test of Premorbid Functioning 
TSH 
 
Thyroid Stimulating Hormone 
UCH-L1 
Ubiquitin Carboxy-Hydrolase-L1 
WAIS-III 
Wechsler Adult Intelligence Scale – 4th edition 
 
 

 
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1. 
ETHICS/PROTECTION OF HUMAN SUBJECTS 
 
1.1  
Institutional Review Board (IRB) 
This study will be conducted in compliance with current Good Clinical Practices (GCP) and Title 21 Part 56 of 
the United States of America Code of Federal Regulations (CFR) relating to IRBs. 
 
1.2  
Ethical Conduct of Study 
The study will be conducted in accordance with GCP defined by the International Conference on Harmonisation 
(ICH) and the ethical principles of the Declaration of Helsinki. 
 
1.3  
Subject Information and Consent  
This study will be conducted in compliance with Title 21 Part 50 of the United States of America Code of Federal 
Regulations (CFR), Federal Regulations, and ICH Guidance Documents pertaining to informed consent. At the 
first visit, prior to initiation of any study-related procedures, subjects will be informed about the nature and 
purpose of the study, participation/termination conditions, and risks and benefits. Subjects will be given adequate 
time to ask questions and become familiar with the study prior to providing consent to participate. Subjects will 
give their written consent to participate in the study and will be provided with a copy of the fully executed consent 
form for their records. 
 
If the subject is not fully competent and able to provide consent, he or she will not be eligible to participate in 
this study. Our study population of scientific interest are individuals with persistent symptoms related to the 
novel coronavirus SARS-CoV-2 (COVID19); subjects in this category will be expected to have full capacity to 
consent unless due to another exclusionary factor.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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2. 
INTRODUCTION: BACKGROUND INFORMATION AND SCIENTIFIC RATIONALE 
 
2.1 Background Information 
 
2.1.1  SARS-CoV-2 infection  
There have been over 22 million cases and 350,000 deaths from COVID19 infection in the USA to date, and >5-
fold these numbers worldwide1. COVID19 infects people of all ages and backgrounds, but it is more common 
and severe in older adults, people with pre-existing conditions, and racial and ethnic minorities2,3. COVID19 is a 
multi-system disease, especially affecting immune, respiratory, cardiovascular, gastrointestinal, musculoskeletal 
and nervous systems4-6. Initially thought to be an acute illness like the flu, resulting in death for some or full 
recovery in most, we are now appreciating that substantial numbers of COVID19 illness survivors experience 
persistent, significant and sometimes disabling symptoms. Variously called "Long-COVID," "COVID long-
haulers," or "chronic COVID syndrome", some of the most prominent symptoms are neurologic and 
neuropsychiatric, including cognitive impairment ('brain fog'), headache, neuropathy and paresthesias, muscle 
aches and weakness, as well as systemic symptoms of fatigue, shortness of breath, hair loss and pain5,7-9. As a 
new clinical entity, little is yet known about the nature of Long-COVID and virtually nothing about its 
management. 
 
2.1.2  Nicotinamide Riboside Rationale 
Nicotinamide riboside (NR) is a form of vitamin B3, naturally found in low levels in milk, that is a precursor to 
nicotinamide adenine dinucleotide (NAD+). NAD+ is a central metabolic cofactor that functions as the primary 
electron donor in the mitochondrial respiratory chain, regulates the activity of various metabolic pathway enzymes 
in glycolysis, Kreb’s cycle, and fatty acid oxidation and enables signaling for major cellular metabolism processes 
involving sirtuins (Figure 1)10,11. These processes are critical for maintenance of synaptic plasticity and protection 
against neurodegeneration. Neuronal mitochondrial dysfunction occurs with advancing age, but this is especially 
pronounced in pathological brain aging, such as with AD or vascular cognitive impairment. NR is a safe, well-
tolerated, potent NAD+ precursor available as a “generally recognized as safe” (GRAS) dietary supplement12. It 
has promising pharmacokinetic and systemic pharmacodynamics properties and has been shown to ameliorate 
bioenergetic, behavioral and pathological abnormalities in mouse models of neurodegeneration13-15. 
 
12 
 
Figure 1. Nicotinamide riboside (NR) enters the NAD+ salvage pathway through conversion to nicotinamide 
mononucleotide (NMN) via nicotinamide riboside kinase (NRK) or conversion to nicotinamide (NaM) via purine 
nucleoside phosphorylase (PNP). From there, NMN (or NaM after modification by NAMPT) is converted into active 
NAD+ and shunted into a variety of metabolic processes. NAD+ consuming enzymes, such as sirtuins, drain the NAD+ 
pool, which must be replenished. Declining activity of nicotinamide phosphoribosyltransferase (NAMPT) with age is 
implicated in declining levels of NAD+ with age. NR supplementation bypasses this rate-limiting step by introducing 
NAD+ precursors directly into the salvage pathway16. 

 
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2.1.3 Nicotinamide Riboside and SARS-CoV-2  
SARS-CoV-2 is predicted to preferentially localize to mitochondria and it has recently been shown to disrupt 
the NAD metabolome17. It has been suggested that SARS-CoV-2 dysregulates NAD gene set. Particularly, it 
has been shown to down-regulate the synthesis of NAD from tryptophan and nicotinic acid (NA), and to up-
regulate the synthesis capacity from NR18. SARS-CoV-2 is also known to induce a cytokine storm that 
increases the circulation of inflammatory cytokines (e.g. Interleukin 1, tumor necrosis factor alpha)19,20. As 
such, it has been hypothesized that NR may be an effective intervention for COVID-19 by increasing NAD+ 
levels and reducing inflammation18. Most recently, a randomized, open-label, placebo-controlled, phase 2 trial 
examined the effect of a combination of L- serine, N-acetyl-L-cysteine (NAC), NR, and L-carnitine tartrate in 
the recovery of individuals with COVID-19, over a 14-day period21. Findings showed that the combination of 
these metabolic cofactors significantly reduced time of recovery (Figure 2)21. 
 
 
Figure 2. Kaplan-Meier curve for all 93 participants enrolled in the clinical trial that tested a combined metabolic cofactor 
supplementation in individuals infected with COVID-19. 
 
2.1.4 Pharmacokinetics of Nicotinamide Riboside in Humans  
 
An open-label, non-randomized study of the pharmacokinetics of NR carried out at the University of Washington 
demonstrated both the impact of NR on NAD+ levels in humans and its tolerability16. Eight subjects underwent 
dose escalation from 250 mg of NR twice daily to 1000 mg of NR twice daily over the course of nine days, with 
NR and NAD+ levels determined at baseline Day 1 and over the course of a 24-hour pharmacokinetic study on 
Day 9. No adverse events were reported in clinical laboratory values, including potassium, which had been noted 
to be elevated in previous NR studies. Slight, but significant decreases in hematocrit, hemoglobin, and platelet 
count were reported. All but one subject showed an increase in blood NR levels from baseline to Day 9, ranging 
from 10% to 127% increases. Blood NR showed exponential decline from 3 to 12 hours with a half-life of 2.7 
hours. Despite relatively fast clearance of NR, blood NAD+ levels were significantly increased to steady state (see 
Figure 3) by 35 to 168% from baseline. NR treatment did not produce side effects commonly seen in niacin 
treatment, such as flushing, pruritus, hyperglycemia, hyperuricemia, or elevation of liver or muscle enzymes. 
However, a variability in NR bioavailability was observed, suggesting that NR relies on active transport across 
intestinal mucosa, which can vary highly from person to person.  

 
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Figure 3. Blood NR and NAD+ levels in n = 8 subjects following NR dose escalation from 250 to 1000 mg twice daily.6 
 
2.1.5  Prior Clinical Use of Nicotinamide Riboside   
NR has been characterized to be both tolerable and effective in healthy middle-aged and older adults in 
improving markers of cardiovascular health in healthy middle-aged and older adults. A 12-week randomized, 
double-blind, single-crossover trial provided 30 healthy subjects with twice daily 600 mg doses of NR for 6 
weeks and 6 weeks of placebo (PBO)12. Over the course of the study, 14 treatment-emergent adverse events 
(AEs) were reported in 7 subjects, all of mild severity. During the NR treatment period, AEs included nausea, 
flushing, leg cramps, and increased bruising. During the PBO period, AEs included headache, skin rash, 
flushing, fainting, and drowsiness. Only 2 subjects (less than 10%) dropped out of the study because of these 
AEs, both of whom were in the PBO period. Two out of the three instances of flushing reported also occurred 
during the PBO period, suggesting the AE is likely unrelated to treatment. No significant changes in clinical 
labs were observed, including renal function markers and blood lipid profiles. Blood NAD+ levels increased by 
60% from baseline following NR treatment. A five-fold change in nicotinic acid adenine dinucleotide (NAAD) 
and a 1.5-fold change in a nicotinamide mononucleotide (NMN) were also detected. Adenosine and adenosine 
triphosphate (ATP) levels also increased following NR treatment, demonstrating its robust impact on 
metabolism. When all subjects were grouped, mean systolic and diastolic blood pressure was significantly 
lowered following NR treatment, and carotid-femoral pulse wave velocity, a gold-standard marker of aortic 
stiffness, was also reduced, although not significantly. NR treatment did not correspond to any significant 
change in total energy expenditure, oxidative fuel source, physical activity patterns, body mass index, glucose 
and insulin regulation, and exercise capacity in any subject.  
 
3. 
SPECIFIC AIMS 
 
3.1 
Overall Study Design and Plan  
The study uses a double-blinded, placebo lead-in, randomized, parallel group, PBO-controlled design. For this 
clinical trial, one-hundred individuals over 17 years of age meeting operationalized criteria for Long-COVID will 
be recruited. These 100 participants will undergo a placebo lead-in period of two weeks. Sixty participants will 
then be randomized to NR (TruNiagen, Chromadex) 1000 mg twice daily for 22 weeks, and 40 will receive 
placebo for the next 10 weeks followed by NR for 10 weeks. Outcomes will consist of standardized cognitive, 
neuropsychiatric, physical, functional and biomarker assessments as well as daily sleep and activity monitoring 
with wearable actigraphy. 

 
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The study will also help better understand the nature of long-COVID by comparing this group with a healthy 
control group of individuals who were infected with COVID-19 but fully recovered. To better address this aim, 
we will also increase our sample size of individuals with long-COVID by testing individuals with long-COVID 
ages 18 and older who will only complete 1 visit. Comparing these groups will help establish differences in 
NAD+ levels at baseline associated with long-COVID, as well as help elucidate the cognitive profile, 
neuropsychiatric and physical functioning, and markers of glia and neural functioning in this population. 
Participants in these additional cohorts will only complete one visit and will not be administered NR or PBO.  
 
3.2 
Study Objectives  
 
The primary objective of the study will be: 
 
1. To measure the effect of NR vs PBO on standard assessments of cognition and subjective cognitive 
concerns. 
 
The secondary clinical objectives of the study will be: 
 
2. To measure the effect of NR vs PBO on neuropsychiatric symptoms; 
3. To measure the effect of NR vs PBO on physical functioning. 
 
The tertiary clinical objective of the study will be: 
1. To elucidate how NAD+ levels, cognitive functioning, neuropsychiatric and physical symptoms, and 
markers of neural injury and inflammation differ between individuals with long-COVID and healthy 
controls. 
 
The exploratory biomarker objectives of the study will be: 
1. To measure the effect of NR on plasma biomarkers of metabolic target engagement and central nervous 
system (CNS) neural and glial integrity measurable in blood. 
2. To measure the effects of NR on cerebral neurophysiology (in an optional sub-study) using resting state 
functional magnetic resonance imaging (rs-fMRI). Connectivity will be measured with rsBOLD. 
 
3.2.1 Standardized Cognitive, Functional, and Neuropsychiatric Outcome Measures 
 
The primary outcome of this study will be objective measures of cognitive performance and subjective cognitive 
concerns measured with the following tests:  
o The Mini-Mental State Examination (MMSE)22, Wechsler Adult Intelligence Scale-Fourth 
Edition (WAIS-IV) Digit Span backwards23, Repeatable Battery for the Assessment of 
Neuropsychological Status (RBANS)24, the Trail Making Test (TMT)25, the Delis-Kaplan 
Executive Function System (DKEFS) Verbal Fluency26, and the Continuous Performance Test 
(CPT). 27 Subjective ratings of everyday cognitive functioning will be measured using items from 
the Behavior Rating Inventory of Executive Function (BRIEF-A)28 at week 2, week 12 and week 
22, and the Everyday Cognition scale (ECog)29 will be measured at each visit.  
 
The secondary and tertiary clinical and exploratory biomarker outcomes of this study will be: 
• Assessment of neuropsychiatric symptoms as measured by:  

 
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o Ratings of mood and anxiety will be measured using the Post Traumatic Stress Disorder Checklist-
Civilian (PCL-C)30, Beck Anxiety Inventory (BAI)31 and Beck Depression Inventory (BDI)32. 
These standard measures will be administered at each visit.  
• Assessment of physical functioning as measured by: 
o The Fatigue Severity Scale33.  
o Objective daily physical activity levels and sleep data collected using wrist actigraphy (Fitbit 
Charge 4).   
o Subjective sleep ratings (Pittsburgh Sleep Quality Index)34 and physical activity (International 
Physical Activity Questionnaire [IPAQ])35 measures will be collected using questionnaires at 
each visit.  
• Safety and tolerability will be assessed with adverse event (AE) reporting conducted at every visit.   
• Plasma for biomarkers will be collected at Week 2, and at every 5 weeks until the end-of-study, and at 
the one-time visit for HC and long-covid participants. Plasma biomarkers assays will consist of ultra-
sensitive immunochemical measures of proteins reflecting neurodegeneration/neural injury (e.g. NfL, 
IL-6 and GFAP), as well as NAD+/NADH). 
• Cerebral neurophysiology will be measured with functional MRI (optional sub-study).   
o Optional MRI will be conducted at two time points: Week 2 and End of Study (Week 22). 
Healthy controls will complete the MRI at their one-time visit. Each MRI scan session will 
include functional MRI with resting state BOLD (rs-fMRI) and pseudo-continuous arterial spin 
labeling (pCASL) sequences. rs-fMRI measures spontaneous yet synchronized fluctuations in 
the BOLD signal to determine the strength of functional connectivity within various intrinsic 
brain networks (i.e., default mode network). pCASL quantifies regional cerebral blood flow 
using magnetically labeled blood water content and will serve as a marker of resting state 
cerebral perfusion that has also been shown to correlate with regional brain metabolism and 
levels of neuronal activity.  
 
3.3  
Protocol Adherence 
Each investigator must adhere to the protocol detailed in this document and agree that any changes to the 
protocol must be approved by Internal Review Board (IRB). Each investigator will be responsible for enrolling 
only those study subjects who have met protocol eligibility criteria. 
 
4.  
SUBJECT SELECTION 
 
4.1 
Inclusion and Exclusion Criteria   
 
4.1.1  Inclusion Criteria  
A subject will be eligible for participation in the clinical trial if they meet the following: 
1. Ages 18 to 65 years; 
2. History of SARS-CoV-2 PCR+ or COVID-19 Antigen Rapid Self-Test at least 2 months prior to study 
entry;  
3. SARS-CoV-2 negative (PCR) at study entry; 
4. Persistent cognitive difficulties (esp. "brain fog") that began around the time of the acute COVID-19;  
5. At least two neurological and/or physical symptoms that started at COVID-19 infection and are ongoing 
at study entry, including fatigue, weakness, headache, loss of smell, tingling/numbness, shortness of 
breath, loss of appetite, palpitations/tachycardia, hair loss, musculoskeletal and/or chest pain; 
6. Minimum score of 18 on the MMSE; 
7. Education level, language skills, and literacy indicates participant is able to complete all assessments; 

 
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8. Willing and able to consent, complete all assessment and study procedures. 
  
A subject will be eligible to participate as a HC Participant for a one time visit if they meet the following: 
1. Ages 18 or older; 
2. History of SARS-CoV-2 PCR+ or COVID-19 Antigen Rapid Self-Test+ at least 2 months prior to study 
entry;  
3. SARS-CoV-2 negative (PCR) or COVID-19 Antigen Rapid Self-Test at study entry; 
4. Experienced full recovery and does not have persistent cognitive difficulties, neurological and/or physical 
symptoms associated with COVID-19 infection; 
5. Minimum score of 18 on the MMSE; 
6. Education level, language skills, and literacy indicates participant is able to complete all assessments; 
7. Willing and able to consent, complete all assessment and study procedures. 
 
A subject will be eligible to participate as a long-COVID Participant for a one time visit if they meet the 
following: 
1. Ages 18 or older;  
2. History of positive SARS-CoV-2 PCR or COVID-19 Antigen Rapid Self-Test at least 2 months prior to 
study entry;  
3. Negative COVID-19 Antigen Rapid Self-Test at study entry; 
4. A minimum score of 18 on the Mini-Mental state examination;  
5. Report persistent cognitive difficulties ("brain fog") that began around the time of the acute COVID19 
illness;  
6. At least two neurological and/or physical symptoms that started at COVID-19 infection and are ongoing 
at study entry, including fatigue, weakness, headache, loss of smell, tingling/numbness, shortness of 
breath, loss of appetite, palpitations/tachycardia, hair loss, musculoskeletal and/or chest pain; 
7. Education level, language skills, and literacy indicates participant is able to complete all assessments; 
8. Willing and able to consent, complete all assessment and study procedures. 
 
4.1.2  Exclusion Criteria  
A subject will not be eligible for participation in the clinical trial if they meet any of the following criteria:  
1. Any specific CNS disease history, such as major clinical stroke, brain tumor, normal pressure 
hydrocephalus, multiple sclerosis, delirium, significant head trauma with persistent neurological of 
cognitive deficits or complaints;  
2. Clinically significant unstable medical condition that could affect safety or compliance with the study 
and would, in the opinion of the investigator, pose a risk to the participant if they were to participate in 
the study; 
3. Was intubated due to COVID-19; 
4. History of neuroimaging with evidence of major infarction, injury, infection, or other focal lesions that 
may be related to cognitive dysfunction;  
5. Major active or chronic unstable psychiatric illness (e.g. depression, bipolar disorder, obsessive 
compulsive disorder, schizophrenia) within the previous year; 
6. Current suicidal ideation; 
7. History of alcohol or other substance abuse or dependence within the past two years; 
8. Any significant systemic illness or medical condition that could affect safety or compliance with study; 
9. Laboratory abnormalities in Vitamin B12, Thyroid Stimulating Hormone (TSH), or other common 
laboratory parameters that might contribute to cognitive dysfunction or other abnormalities in 
hematological, hepatic or renal function tests; 

 
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10. Current use of medications with psychoactive properties that in the opinion of the principal investigator, 
may be deleteriously affecting cognition (e.g., anticholinergics, antihistamines, antipsychotics, sedative 
hypnotics, anxiolytics);  
11. Any known hypersensitivity to nicotinamide riboside, or its principal metabolite, nicotinamide 
mononucleotide;  
12. No consumption of dietary supplements containing more than 100mg of niacin, nicotinamide riboside 
(NR), or nicotinamide mononucleotide (NMN) as the primary agents 30 days prior to baseline and for 
the duration of the trial.  
13. Use of other investigational agents or interventions one month prior to entry and for the duration of the 
trial; 
14. If participating in the optional MRI sub-study: Any contraindication to undergo MRI studies, such as 
history of cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head, 
prosthetic heart valves, and/or severe claustrophobia impeding ability to participate in an imaging study; 
15. Pregnant people or those who are planning to become pregnant within 7 months from study entry. 
 
A subject will not be eligible to participate as a HC participant if they meet any of the following criteria:  
1. Any specific CNS disease history, such as major clinical stroke, brain tumor, normal pressure 
hydrocephalus, multiple sclerosis, delirium, significant head trauma with persistent neurological of 
cognitive deficits or complaints;  
2. Clinically significant unstable medical condition that could affect safety or compliance with the study 
and would, in the opinion of the investigator, pose a risk to the participant if they were to participate in 
the study; 
3. Was intubated due to COVID-19; 
4. History of neuroimaging with evidence of major infarction, injury, infection, or other focal lesions that 
may be related to cognitive dysfunction;  
5. Major active or chronic unstable psychiatric illness (e.g. depression, bipolar disorder, obsessive 
compulsive disorder, schizophrenia) within the previous year; 
6. Current suicidal ideation; 
7. History of alcohol or other substance abuse or dependence within the past two years; 
8. Any significant systemic illness or medical condition that could affect safety or compliance with study; 
9. Current use of medications with psychoactive or other properties that in the opinion of the principal 
investigator, may be deleteriously affecting cognition (e.g., anticholinergics, antihistamines, 
antipsychotics, sedative hypnotics, anxiolytics);  
10. If 65 years of age or younger, have any contraindication to undergo MRI studies, such as history of cardiac 
pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head, prosthetic heart 
valves, and/or severe claustrophobia impeding ability to participate in an imaging study; 
11. Pregnant individuals. 
 
A subject will not be eligible to participate as an long-COVID Participant if they meet any of the following 
criteria:  
1. Any specific CNS disease history, such as major clinical stroke, brain tumor, normal pressure 
hydrocephalus, multiple sclerosis, delirium, significant head trauma with persistent neurological of 
cognitive deficits or complaints;  
2. Clinically significant unstable medical condition that could affect safety or compliance with the study 
and would, in the opinion of the investigator, pose a risk to the participant if they were to participate in 
the study; 
3. Was intubated due to COVID-19; 

 
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4. History of neuroimaging with evidence of major infarction, injury, infection, or other focal lesions that 
may be related to cognitive dysfunction;  
5. Major active or chronic unstable psychiatric illness (e.g. depression, bipolar disorder, obsessive 
compulsive disorder, schizophrenia) within the previous year; 
6. Current suicidal ideation; 
7. History of alcohol or other substance abuse or dependence within the past two years; 
8. Any significant systemic illness or medical condition that could affect safety or compliance with study; 
9. Current use of medications with psychoactive or other properties that in the opinion of the principal 
investigator, may be deleteriously affecting cognition (e.g., anticholinergics, antihistamines, 
antipsychotics, sedative hypnotics, anxiolytics);  
10. If 65 years of age or younger, have any contraindication to undergo MRI studies, such as history of cardiac 
pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head, prosthetic heart 
valves, and/or severe claustrophobia impeding ability to participate in an imaging study; 
11. Pregnant individuals. 
 
 
4.1.2.1 Individuals of Childbearing Age 
Individuals of childbearing age will be eligible for the study. However, pregnant individuals will be ineligible 
for the clinical trial and sub-studies studies, and those who are planning to become pregnant within 7 months 
from study entry will be ineligible for the clinical trial. 
 
4.2 Recruitment   
Approximately 120 subjects with long-COVID will be screened, and after screening, approximately 100 
subjects are expected to complete the clinical trial. Approximately 75 healthy controls (50 participants <65 
years of age, and 25 participants >65 years of age) and 75 long covid participants (50 participants <65 years of 
age, and 25 participants ≥65 years of age) are expected to complete the one-time visit. All subjects in the long-
COVID group participating in the clinical trial will be given the option to participate in the optional repeat MRI 
sub-study until 24 subjects have completed the sub-study, and 50 more can complete the baseline MRI. All 50 
healthy controls and 50 long-COVID participants <65 years of age are required to complete the MRI at their 
one-time visit. Individuals older than 65 years will not complete an MRI. 
 
4.2.1 Recruitment of Subjects through Advertising  
Advertisement flyers will be posted on bulletin boards around MGH (both the main campus and Charlestown 
campus) to advertise for the study as well as ad advertisement on Partners Rally for Research. Advertisement 
flyers will also be provided at community events (e.g., health fairs) and other institutions (e.g., churches, 
community centers). An email address and phone number will be provided that will ring directly to the research 
coordinator, and voice messages can be left for the coordinator on a password-protected voice mailbox. 
Additionally, for participants collected through Rally, we will email them a survey to complete via REDCap 
using send secure. This digital survey will allow us to assess their eligibility. Once participants submit the 
survey and are deemed eligible, we will contact them by phone to ask any follow-up questions, collect more 
information as needed, and schedule them for an in-person visit. We may still pre-screen people by phone if the 
person communicates that this is their preferred method. 
 
4.2.2 Recruitment of Subjects Identified through Private Medical Information 
The Neuro-Infectious Diseases Unit, Neurology Clinic, Psychological Assessment Center, Multicultural 
Assessment and Research Center, MGH Primary Care clinics, the NeuroScience dashboard, and 
Neuropsychiatric Clinic physicians will be made aware of the study, including eligibility criteria. If they feel 

 
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that a patient of theirs may be a candidate for the study, they will obtain the patient’s permission to be contacted 
by the study staff or provide a flyer with the study’s information. Those who agree to be contacted will be 
contacted by the study coordinator who will explain the study in further detail and if the subject is interested, 
potentially complete a telephone or online prescreening survey.   
 
4.2.3 Recruitment of Subjects from the MGH McCance Center for Brain Health 
Some subjects will be recruited from the study titled “Brain Health in COVID-19 survivors and their 
caregivers” at the MGH McCance Center for Brain Health (IRB protocol 2020P001455).  
 
4.2.4 Recruitment of Subjects from Among the Investigators’ Own Patients  
Dr. Steven Arnold (co-investigator) is a neurologist in the MGH Memory Disorders Unit and Dr. Guzmán-
Vélez a neuropsychologist at the Multicultural Assessment and Research Center. Subjects may also be recruited 
from among their patients. Special care will be taken to ensure patients are aware that their participation is 
completely voluntary and that their decision to participate will not affect their care. Dr. Arnold and Dr. 
Guzmán-Vélez will obtain the patient’s permission to be contacted by the study staff or provide a flyer with the 
study’s information. If interested, the patient will be contacted by the study coordinator who will explain the 
study in further detail and if the subject is interested, potentially complete a telephone or online prescreening 
survey. 
 
5.  
SUBJECT ENROLLMENT 
 
5.1 
Informed Consent Process  
This study will be conducted in compliance with Title 21 Part 50 of the United States of America Code of 
Federal Regulations (CFR), Federal Regulations, and ICH Guidance Documents pertaining to informed consent.  
 
Potential subjects will be given general information about the research (e.g., through informational sheets, letters, 
or discussion with their treating physicians). If they are interested in learning more about the study, they will then 
contact the research coordinator. The research coordinator will obtain verbal consent in accordance with Partner’s 
Prescreening Guidelines prior to performing a telephone prescreening interview. Subjects who meet pre-screening 
criteria for the clinical trial and wish to continue the screening process will be scheduled for a screening visit that 
will take place in person at MGH CNY campus. Subjects who are eligible as HC or long-COVID participants 
based on the phone screening will be scheduled for their one-time visit that will take place in person at MGH 
CNY campus. 
 
At the clinical trial’s screening visit and the one time visit for the HC and long-COVID participants, the 
investigator will meet with the potential subject to review and discuss the details of the study using the informed 
consent document as a guide. A copy of the informed consent document will be sent to the subject before the 
first visit takes place, and they will have at least 24 hours between when the document is received and when the 
first visit is scheduled in order for the subject to have adequate time to fully review the Informed Consent 
Document.  
 
The informed consent process will be conducted using a REDCap-based electronic consent form. The consent 
form has been developed in REDCap, a secure, web-based, HIPAA-compliant, data collection platform with a 
user management system allowing project owners to grant and control varying levels of access to data collection 
instruments and data for other users. If requested by the subject, a traditional hard copy consent form will be 
provided to the subject along with any materials needed for return shipping. 
 

 
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During the first visit, the informed consent document will be reviewed with the participant by a licensed 
clinician investigator. The potential subject may ask to speak with the physician investigator should a non-
physician investigator be involved in obtaining informed consent. The informed consent discussion will include 
all of the required elements of informed consent, including the purpose of the research, the procedures to be 
followed, the risks and discomforts, as well as potential benefits associated with participation, and alternative 
procedures to study participation. Their questions will be answered to their satisfaction. The subject will be 
provided with adequate time to reflect on the potential benefits and risks and possible discomforts of 
participation, and to make an informed decision. 
 
If the subject agrees to participate in the study, a link will be sent to the REDCap e-consent form or the subject 
will sign the provided hard-copy informed consent form. For REDCap e-consent, subject signatures will be 
obtained using electronic signature via mouse followed by electronic signature by the doctorate-level clinician 
investigator. The signed hard-copy consent forms will then be signed by the consenting investigator. Upon 
completion of the informed consent process, subjects will be provided with a hard copy of the signed consent 
from and hard copies will be stored in each subject’s binder.  
 
All subjects must be deemed capable of providing informed consent by the Investigators. Subjects who are not 
deemed capable of providing informed consent will be excluded from this study.  
 
5.2  
Remuneration 
Subjects for the clinical trial will receive $20 for their participation in each visit. If subjects elect to participate 
in MRIs, they will receive $100 for each MRI. Subjects who are part of the clinical trial will also receive $20 
upon completion of the study as long as they were at least 80% compliant with all study activities, including 
taking their medication, completing cognitive tests, and completing the Fitbit activity tracking. Therefore, if a 
subject elects to undergo all additional procedures, the maximum amount a subject would be eligible to receive 
is $320 at study completion. If a subject does not elect to participate in any optional procedures but is compliant 
with study tasks, they would be eligible to receive $120. We anticipate some subjects may come from outside 
the region and if so, appropriate travel expenses may be reimbursed including transportation up to $15 per visit. 
To minimize the inconvenience of frequent visits, meal and parking vouchers for use at the MGH Charlestown 
Navy Yard (CNY) facilities will also be offered at each visit. 
 
Long-COVID and HC participants who are 65 years of age or younger will receive $120 for their participation 
in the one-time visit. If they live outside the region, appropriate travel expenses may be reimbursed including 
transportation up to $15 for the visit. Meal and parking vouchers for use at the MGH CNY cafeteria and parking 
garage will also be offered. 
 
Long-COVID and HC participants who are older than 65 years of age, we will pay $80 for their participation in 
the one-time visit. If they live outside the region, appropriate travel expenses may be reimbursed including 
transportation up to $60 for the visit. Meal and parking vouchers for use at the MGH CNY cafeteria and parking 
garage will also be offered. 
 
 
 
 
 
 
 

 
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5.3 
Randomization  
Subjects in the clinical trial will be randomized into one of two groups (see Figure 4 below). Randomization 
will be done by MGH Clinical Trials Pharmacy.  
 
 
Figure 4. Study Schema 
 
5.4 
Reasons for Withdrawal  
A study subject will be discontinued from participation in the study if:  
• 
Any clinical adverse event (AE), concurrent illness, or other medical condition or situation occurs 
such that continued participation in the study would not be in the best interest of the subject.  
• 
The subject meets any exclusion criteria (either newly developed or not previously recognized). 
• 
Tests positive for SARS-CoV-2 PCR or COVID-19 Antigen Rapid Self-Test 
• 
The subject is less than 80% or greater than 120% compliant with NR dosing.  
Subjects are free to withdraw from participation in the study at any time upon request.  
 
5.4.1  Handling of Withdrawals  
A subject may choose to discontinue participation in the study at any time. An Early Termination visit will 
occur when a subject withdraws consent, i.e. withdrawing his or her participation in future study procedures. 
 
5.5  
Termination of Study  
This study may be prematurely terminated if, in the opinion of the investigator, there is sufficient reasonable 
cause.  
 
Circumstances that may warrant termination include, but are not limited to:  
• 
Determination of unexpected, significant, or unacceptable risk to subjects.  
• 
Unsatisfactory enrollment. 
• 
Insufficient adherence to protocol requirements.  
• 
Data that are not sufficiently complete and/or evaluable.  
 

 
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If the study is prematurely terminated or suspended, the investigators will promptly inform the institution and 
regulatory authorities of the termination or suspension and the reason(s) for the termination or suspension. The 
IRB/IEC will also be informed promptly and provided the reason(s) for the termination or suspension by the 
investigator, as specified by applicable regulatory requirement(s).

 
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6. 
STUDY PROCEURES   
 
6.1 
 Schedule of Assessments for the clinical trial 
 
Activity (n=100) 
Week 0 
Week 2 
Week 7 
Week 12 
Week 17 
Week 22 
Early DC 
Week 24 
Screening/Lead-
In 
Baseline 
Visit 1 
Visit 2 
Visit 3 
Visit 4 
Phone 
Follow Up 
Informed Consent1 
X 
  
  
  
  
  
  
  
Demographics 
X 
  
  
  
  
  
  
  
Medical & COVID-19 History/ 
Safety Labs2,3 
X 
  
  
  
  
  
  
  
Long COVID-19 symptoms 
assessment 
X 
X 
X 
X 
X 
X 
X 
X 
SARS-CoV-2 PCR test 
X 
  
  
  
  
  
  
  
Height and Weight 
X 
  
  
X 
  
X 
X 
  
Vital Signs 
X 
 X 
X 
X 
X 
X 
X 
  
Inclusion/ Exclusion Review4 
X 
X 
X 
X 
X 
X 
  
  
Physical and Neurological 
Examination5 
X 
 
  
X 
  
X 
X 
  
MMSE 
X 
  
  
X 
  
X 
X 
  
Concomitant Medications and 
Supplements4  
X 
X 
X 
X 
X 
X 
X 
X 
Randomization 
X 
  
  
  
  
  
  
  

 
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Dispense NR/PBO4 
X 
X 
X 
X 
X 
  
  
  
Accountability and Compliance 
  
X 
X 
X 
X 
X 
X 
  
AE Reporting4,6 
  
X 
X 
X 
X 
X 
X 
      X 
Office Cognitive Assessment7 
 
X 
  
X 
  
X 
X 
  
Neuropsychiatric Assessment8 
X 
X 
X 
X 
X 
X 
X 
  
Office Functional Assessment 
  
X 
  
X 
  
X 
X 
  
Blood Collection for PK and 
Biomarkers9 
  
X 
X 
X 
X 
X 
X 
  
Subjective cognitive concerns 
assessment10 
X 
X 
X 
X 
X 
X 
X 
  
Physical activity Assessment11 
X 
X 
X 
X 
X 
X 
X 
  
Sleep Assessment12 
 X 
X 
X 
X 
X 
X 
X 
  
Daily Activity Assessment12 
______________________________ongoing________________ 
ongoing___X 
  
  
 
6.2 
 Schedule of Assessments for the one-time visits 
 
Activity 
Healthy Control (n=75)  
Long-COVID Participant (n=75)  
One Time Visit 
One Time Visit 
Informed Consent1 
X 
X  
Demographics 
X 
X 

 
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Medical & COVID-19 History 
X 
X 
Long COVID-19 symptoms assessment 
- 
X 
SARS-CoV-2 PCR test 
X 
X 
Height and Weight 
X 
X 
Vital Signs 
X 
 X 
Inclusion/ Exclusion Review4 
X 
X 
SMMSE 
X 
X 
Concomitant Medications and Supplements4  
X 
X 
AE Reporting4,5 
X 
X 
Office Cognitive Assessment6 
X 
X 
Neuropsychiatric Assessment7 
X 
X 
Office Functional Assessment 
X 
X 
Blood Collection for PK and Biomarkers8 
X 
X 
Subjective cognitive concerns assessment9 
X 
X 
Sleep Assessment11 
 X 
X 
 
1No study procedures apart from the telephone pre-screening visit will be performed prior to the signing of the informed consent form (ICF). All subjects will sign an ICF prior to undergoing any study 
tests or procedures.  
2After initial assessment of medical history during the screening period, updated medical history will be collected in subsequent visits.  
3Safety labs include Hematology (CBC with differential), Complete Chemistry Panel, Liver Function Tests, B12 and TSH, as well as a pregnancy test to women of childbearing potential. 
4These procedures can take place virtually via Zoom videoconference if necessary. 

 
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5All adverse events that occur AFTER signing consent form until the end of the follow up visit will be included. 
6Including D-KEFS Verbal Fluency, Trail Making Test, RBANS, WAIS-IV Digit Span Backwards, BRIEF-A, CPT.  
7Including BDI, BAI, PCL-C  
8Including collection of dried blood spot samples 
9ECog 
10IPAQ 
11Pittsburgh Sleep Quality Index 
12Fitbit Charge 4 Wearable Device 
 
 
 
 

 
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6.2.1 Screening/Lead-In Visit (Week 0) 
The screening procedures will determine the subject’s eligibility for the study and will take approximately 3 
hours.  
 
The following procedures will take place at the Screening/Lead-In visit:  
• Obtain written informed consent from the subject.  
• Obtain demographics and medical history, including assessment of COVID-19 symptoms 
• Complete SARS-CoV-2 PCR test 
• Safety Labs 
• Perform physical and neurological examination 
• Measure Vital Signs  
• Measure height and weight 
• Review and document concomitant medications, supplements, and therapies 
• Administer the MMSE 
• 
Provide Fitbit  
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity, and others. 
• Dispense PBO  
 
6.2.1.1 Screen Failures 
Any subject who signs consent will be considered enrolled in the study. If a subject fails screening, at a 
minimum, the following information should be captured and entered into the Electronic Data System (EDC). 
• Inclusion/Exclusion Criteria  
• Demographics   
• Reason for screen failures 
 
6.2.2 Baseline Visit (Week 2)  
The following procedures will be performed and will take approximately 4-5 hours depending on participation 
in the MRI sub-study. If the subject has elected to participate in the MRI sub-study, the visit may occur over 
multiple days as long as all tasks are completed during the study visit window. 
• 
Measure Vital Signs  
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Assess study supplement compliance  
• Assess COVID-19 related symptoms 
• Administer cognitive assessments 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity and others  
• Assess and document AEs and changes to medical history1  
• Review and document concomitant medications, supplements, and therapies1 
• Dispense study supplement or PBO1  
• Perform optional MRI scan 
• Reassess inclusion and exclusion criteria1  
1These procedures can take place virtually via Zoom videoconference if necessary. 
 
6.2.3    Follow Up Visits (Weeks 7, 12 and 17) 
These visits will take place every 5 weeks (± 2 days) following Baseline.  

 
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• Review and document concomitant medications, supplements, and therapies1 
• Assess COVID-19 related symptoms 
• Perform physical assessments  
• Perform physical and neurological examination 
• Measure vital signs 
• Dispense study supplement or PBO1 
• Assess study supplement compliance  
• Administer battery of cognitive assessments (only week 12) 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity and others  
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Assess and document adverse events (AEs) and changes to medical history1 
1These procedures can take place virtually via Zoom videoconference if necessary. 
 
6.2.4 Final study visit 
This visit will take place at Week 22. 
• Measure Vital Signs  
• Perform physical and neurological examination  
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Assess study supplement compliance  
• Assess COVID-19 related symptoms 
• Administer cognitive assessments 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity and others  
• Assess and document AEs and changes to medical history1  
• Review and document concomitant medications, supplements, and therapies1 
• Perform physical assessments  
• Perform optional MRI scan 
1These procedures can take place virtually via Zoom videoconference if necessary. 
 
6.2.5 Early Termination Visit  
If the subject withdraws from the study before completion of all study visits, they will be invited to participate 
in an Early Termination Visit within 7 days of stopping treatment. 
 
• Measure Vital Signs  
• Perform physical and neurological examination  
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Assess study supplement compliance  
• Assess COVID-19 related symptoms 
• Administer cognitive assessments 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity, and others  
• Assess and document AEs and changes to medical history1  
• Review and document concomitant medications, supplements, and therapies1 
• Perform optional MRI scan 
1These procedures can take place virtually via Zoom videoconference if necessary. 
 

 
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6.2.6 HC One Time Visit 
Healthy control subjects will only complete one visit.  
• Obtain written informed consent from the subject.  
• Obtain demographics and medical history, including assessment of COVID-19 symptoms 
• Complete SARS-CoV-2 PCR test or a rapid antigen test 
• Measure Vital Signs  
• Measure height and weight 
• Administer the MMSE 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity and others. 
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Administer cognitive assessments 
• Perform MRI scan (if participant is <65 years of age) 
6.2.7 Long-COVID One Time Visit 
Long-COVID participants will only complete one visit.  
• Obtain written informed consent from the subject.  
• Obtain demographics and medical history, including assessment of COVID-19 symptoms 
• Complete SARS-CoV-2 PCR test or a rapid antigen test 
• Measure Vital Signs  
• Measure height and weight 
• Administer the MMSE 
• Administer questionnaires about neuropsychiatric symptoms, sleep, physical activity and others. 
• Blood draw and a collect dried blood spot sample for biomarker analysis 
• Administer cognitive assessments 
• Perform MRI scan (if participant is 65 years of age or younger) 
 
6.2.8  Protocol Deviations  
A protocol deviation is any noncompliance with the current clinical trial protocol. The noncompliance may be 
on the part of the subject, the PI, or the study staff. As a result of deviations, corrective actions will be 
developed by the PI and implemented promptly. All deviations from the protocol must be addressed in the 
subject’s documents. Protocol deviations will be sent to the IRB per their guidelines and entered in the Protocol 
Deviations Log in the EDC System.  
 
 6.2.9 Missed Visits and Procedures  
Missed visits and any procedures not performed (not attempted) for reasons other than illness or injury will be 
reported as a protocol deviation. Procedures or visits not performed due to illness, injury, or disability, including 
procedures that were attempted but failed (i.e., weight unable to be obtained due to subject immobility) will not 
be reported as protocol deviations. Participants who are unable to attend their visit within the approved 3-day 
window will receive overnight-shipped extension supplements before their original supply runs out. This allows 
them to maintain their supplement regimen until they can come in for their visit. We will confirm their mailing 
address before we send the supplement and provide the tracking number. Signature will be required upon 
delivery. We will also contact them on the date that they receive the supplement to confirm that it arrived in 
perfect condition. 
 
7 
CLINICAL ASSESSMENTS AND OUTCOME MEASURES 

 
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7.1 
Clinical Variables 
Assessments will be performed at designated time-points throughout the study for clinical evaluation. In 
addition to the assessments evaluated below, subjects will provide information on their demographics, past 
medical and COVID-19 history, family history, and concomitant medication usage. 
 
7.1.1  Safety Measures  
 
7.1.1.1 Vital Signs, Height, Weight 
Vital signs, including systolic and diastolic blood pressure, pulse rate (radial artery)/minute, respiratory 
rate/minute, and temperature will be assessed at specified visits. Verbal weight may be documented for those 
subjects utilizing a wheelchair.  
 
7.1.1.2 Clinical Laboratory Assessments  
Study participants in the clinical trial will be asked to provide approximately 20 mL of blood for safety lab 
analysis at screening. The participant will have his or her whole blood collected by either a nurse or 
phlebotomist from a peripheral vein. Blood will be handled, processed, and analyzed in accordance with 
regulations set forth by the American Society for Clinical Pathology and the College of American Pathologists. 
 
The investigator may order additional testing, if thought to be necessary, to further assess an adverse event 
(AE). 
 
7.1.1.3 Adverse Events 
Once the informed consent form has been signed by the subject, inquiry about all adverse events (AEs) will be 
performed at each study visit. The AE grading system being used will be the CTCAE protocol. 
 
7.1.2 Clinical Assessments  
 
7.1.2.1 Neuropsychiatric and Functional Assessments  
 
7.1.2.1.1  Beck Anxiety Inventory (BAI)   
The Beck Anxiety Inventory31 (BAI) is a 21-item, self-administered questionnaire that measures the presence 
and severity of anxiety in psychiatric populations. It was constructed to avoid confounds due to comorbidity of 
depression, and it has been found to be highly valid, reliable, and consistent23. The BAI lists 21 common 
symptoms of anxiety and asks the subject to rate the severity with which they experience each symptom (not at 
all, mildly, moderately, or severely). Scores of 0-21, 21-35, or 36-63 indicate low, moderate, or severe anxiety, 
respectively.  
 
7.1.2.1.2  Beck Depression Inventory (BDI)   
The Beck Depression Inventory32 (BDI) is a widely used assessment of depression severity used in clinical and 
research settings. It is a 21-item, self-administered rating inventory with a mean internal consistency of 0.86. The 
BDI ranks responses to several domains of depression, including mood changes, guilt, self-image, suicidality, 
affect, and apathy on a scale from 0 to 3 and provides an assessment of the level of depression, spanning minimal 
to mild to moderate to severe depression. 
 
7.1.2.1.3  Post Traumatic Stress Disorder Checklist – Civilian (PCL-C) 

 
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The Post Traumatic Stress Disorder Checklist – Civilian (PCL-C)30 is a standardized self-report measure of 
post-traumatic stress disorder (PTSD) that was designed to be applied to any traumatic event. The PCL-C is 
comprised of 17 items that correspond to key symptoms of PTSD as established by the Diagnostic and 
Statistical Manual of Mental Disorders (DSM). 
 
7.1.2.1.4  Behavior Rating Inventory of Executive Function (BRIEF-A) 
The Behavior Rating Inventory of Executive Functioning (BRIEF-A)28 is a standardized rating scale to assess 
self-regulation and executive function in everyday behaviors. It is a 75-item scale including a Behavioral 
Regulation Index consisting of inhibition, shifting, emotional control, and self-monitoring scales and a 
Metacognition Index consisting of initiation, working memory, planning/organization, task monitoring, and 
organization of material scales. This study will only use the BRIEF-A self and not the informant report.  
 
7.1.2.1.5  Pittsburgh Sleep Quality Index 
The Pittsburgh Sleep Quality Index34 is a self-report questionnaire that assesses sleep quality over a 1-month 
time interval. It consists of 19 individual items that are usually completed between 5 to 10 minutes. 
 
7.1.2.1.6  International Physical Activity Questionnaire (IPAQ) 
The International Physical Activity Questionnaire35 is a self-reported measure of physical activity that can be 
administered by telephone interview or self-administration.  The IPAQ collects information on time spent 
walking, in vigorous- and moderate-intensity activity and in sedentary activity. The IPAQ has been attributed 
reasonable measurement properties for monitoring population levels of physical activity among 18- to 65- years 
old adults in diverse settings. 
 
7.1.2.2 Neurocognitive Assessments  
 
7.1.2.2.1 Mini-Mental State Examination (MMSE)  
The Mini-Mental State Examination (MMSE)22 is a widely used cognitive screening measure that includes 
items that measure orientation, attention, memory, language, and visuo-spatial abilities. Scores range from 1 to 
30, with scores greater than 25 being considered normal.  
 
7.1.2.2.2  Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)  
The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)24 is a commonly used 25-
minute, standardized neurocognitive battery assessing functioning across multiple cognitive domains. It is 
designed to be administered repeatably, with several equivalent alternate forms available. The RBANS measures 
a total of five neurocognitive domains using twelve subtests: immediate memory (List Learning and Story 
Memory), visuospatial/constructional (Figure Copy and Line Orientation), language (Picture naming and 
Semantic Fluency), attention (Digit Span and Coding), and delayed memory (List Recall, List Recognition, Story 
Memory, and Figure Recall).  The RBANS will be administered at Baseline, Week 12 , and End of Study (Week 
22) using alternate forms.  
 
7.1.2.2.3   Trail Making Test (TMT) 
The Trail-Making Test (TMT)25 is a graphomotor letter and number-letter sequencing task that will be 
administered to test processing speed, mental flexibility, and set-switching. The test takes approximately 5 
minutes to complete.  

 
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7.1.2.2.4 Wechsler Adult Intelligence Scale – 4th edition (WAIS-IV) Digit Span 
Wechsler Adult Intelligence Scale – 4th edition (WAIS-IV) Digit Span23 is a verbal measure of attention and 
working memory that consists of three tests: 1) digits forward, which requires repeating a string of numbers; 2) 
digits backwards, which requires repeating a string of numbers backwards; and 3) and digit sequencing, which 
requires organizing a string of numbers from lowest to highest. 
 
7.1.2.2.5 Delis-Kaplan Executive Function System (DKEFS) Verbal Fluency 
The Delis-Kaplan Executive Function System (DKEFS) Verbal Fluency26 is a measure of executive functioning 
that is composed of three different conditions: 1) phonetic fluency, which requires listing as many words as 
possible that begin with a specific letter in 60 seconds; 2) semantic fluence, which requires listing as many 
animals as possible in 60 seconds; and 3) category switching requires switching between two semantic 
categories in 60 seconds.  
 
7.1.2.2.6 Everyday Cognition Scale (ECog) 
The Everyday Cognition Scale (ECog)29 is a self-report questionnaire that assesses a global factor and six 
domain-specific factors associated with everyday function and cognition (e.g. memory, planning, organization, 
language, etc). The ECog has been shown to be correlated with objective neuropsychological tests. 
 
7.1.2.2.7 Continuous Performance Test (CPT)  
The Continuous Performance Test is a test of sustained attention and alertness in which subjects are presented 
with a string of letters27. The subject is instructed to press a button every time they see an X and not to press it 
for any other letter. Letters are presented for five minutes. The subject is then given a brief break before 
continuing to the next part of the study, the AX task. In this section, the subject is told to press the button when 
they see an X that follow right after an A but not when there is an X that is not preceded by an A. The subject is 
then presented with another five-minute block of letters. This section of the task is also a test of inhibition and 
executive control. Task administration will utilize Millisecond Inquisit software, a computerized stimulus 
presentation platform optimized for temporally precise stimuli presentation and reaction time recording of 
psychological assessments. The CPT will be administered at Baseline, Week 12 , and End of Study (Week 22).  
Inquisit Web requires only a subject code and no personally identifiable information. 
 
7.1.2.3 Physical Functioning Assessment 
 
7.1.1.3.1 Physical and Neurological Examination 
A physical and neurological examination will be performed at the Baseline visit, Visit 2, and End of Study 
(Week 22). The following systems will be examined: general appearance, head, eyes, ears, nose, throat, neck, 
chest, heart, abdomen, extremities, edema, peripheral vascular, skin and appendages, musculoskeletal, central 
nervous system, muscles and back. COVID-19 related symptoms will be measured using the COVID-19 
checklist and the C19-YRS rehabilitation screening tool. HC and long-COVID participants will not undergo a 
physical and neurological examination. 
 
7.1.2.4   Phlebotomy and collection of dried blood spot samples for Biomarkers 
Subjects will provide additional blood samples for biomarker analysis from Baseline to End of Study visits, and 
HC and long-COVID participants during their one-time visit. Biomarker analysis will include NAD+/NADH, 
cytokines (e.g. IL-6), oxidative stress marker 8-OHdG), Irisin; NfL, Aβ42, Aβ40, tau, GFAP, UCH-L1, and 
other analytes. At each visit (Weeks 0-22), 20 ml (1.3 tablespoons) of blood will be collected for these analyses, 

 
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for a total of 120 ml (7.8 tablespoons) over the course of the study. Subjects will also provide a dry blood spot 
sample with a finger prick to measure the concentration of NAD+ from Baseline to End of Study visits. 
 
7.1.2.5  Magnetic Resonance Imaging (MRI) 
Subjects will be given the opportunity to participate in an optional MRI sub-study at Baseline (Week 0) and End 
of Study (Week 22). Subjects in the healthy control group will complete the MRI at their one-time visit. 
Subjects electing to participate will be asked to complete both MRIs to be part of the sub-study. Data will be 
collected on a 3-Tesla Siemens scanner with the following scan sequences: a high resolution T1-weighted scan, 
T2 FLAIR, resting state BOLD MRI, and pCASL at rest. 
 
Resting state BOLD measures low-frequency spontaneous fluctuations in BOLD signal across time, where 
correlations of this spontaneous activity between brain regions are thought to reflect functional connectivity. 
The 10-minute rsfMRI scan will be acquired with whole-brain echo planar imaging (EPI) time series with a 
voxel size of 2x2x2 mm isotropic, TR/TE = 4000/30 ms, acquisition matrix = 64x64, and 40 axial slices. 
Subjects will be instructed to keep their eyes open throughout the duration of the scan. rsfMRI data will be 
processed within the FreeSurfer FS-FAST stream using standard pre-processing steps including motion 
correction, masking of non-brain tissue, registration to the anatomical high-res image, sampling to the surface, 
and surface smoothing by 5 mm. Temporal filtering to extract signals in the 0.008-0.08 Hz frequency band will 
be performed, followed by linear regression to factor out mean global signal, average signal from white matter, 
and average signal from ventricular cerebrospinal fluid (CSF) regions. To perform functional connectivity 
analyses, we will use a seed-based approach to examine temporal correlations between the mean time course 
within anatomically-defined nodes and the rest of the brain.  
 
ASL-MRI is another indicator of brain function, quantifying regional cerebral blood flow, which in turn is 
linearly coupled to regional brain metabolism and neuronal activity36. It is especially well suited to drug trials in 
which change from baseline is of prime interest. Pseudo-Continuous ASL (pCASL), which provides excellent 
sensitivity and temporal stability37, will be used in the protocol. The single shot pCASL scan will be acquired 
with the following parameters: 24 cm field of view, 2x2x2 mm isotropic, TR/TE = 4300/3.2 ms, acquisition 
matrix = 64x64, slice thickness = 6mm, temporal bolus = 1800 ms with a 1800 ms post labeling delay. 
Corresponding field map scans will also be acquired to correct for blurring and signal dropout during image 
processing. All data processing and analysis will utilize tools available through FSL’s Bayesian Inference for 
Arterial Spin Labeling MRI (BASIL) toolbox. 
 
7.1.2.6  SARS-CoV-2 PCR 
The CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay will be used to measure active COVID-19. 
During the test, the subject is asked to tilt the head back 70 degrees. While gently rotating the swab, a 6-inch 
swab is inserted less than one inch into nostril (until resistance is met at turbinates). 
 
7.1.2.7 The Fatigue severity scale 
The fatigue severity scale33 is a measure of fatigue that contains 10 items. The subjects will be instructed to 
respond to each statement using a scale of 1 to 7, with 1 indicating “Strongly Disagree” and 7 indicating 
“Strongly Agree.”  
 
7.1.3 Daily Outcomes  
 
7.1.3.1  Daily activity and sleep tracking 

 
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Each subject will be provided with a Fitbit Charge 4 that they will wear throughout the study. The device will 
track the participant’s heart rate, activity, and sleep. The subject will be instructed to wear their device at all 
times, except for when it is being charged and when they are bathing. HC and long-COVID participants will not 
be given a FitBit. 
 
7.1.3.1.1 Charging and syncing procedures  
Subjects will be instructed to ensure that the device is charged at all times. The subject will be instructed to 
charge their device when their battery is low (roughly once every 4 days) during a period of inactivity, such as 
when watching TV. The subject will be explicitly instructed not to charge their device during times of sleep. 
The subject will be instructed to sync their device at least 3 times per week. Charging and syncing compliance 
will be routinely monitored by a study coordinator. The coordinator will conduct periodic reviews of the 
subject’s charging and syncing compliance by logging onto the subject’s Fitbit dashboard. If the device has not 
been appropriately charged or synced, the study coordinator will contact the subject to remind them to sync or 
charge their device as needed. If a subject requires more than three such reminders, they will be considered non-
compliant, and the PI will determine if the subject should continue in the study or if their study participation 
should be discontinued. 
 
7.2  Training and Validation 
All evaluators must be certified by the study PI to perform cognitive and psychiatric outcome assessments. It is 
strongly preferred that a single evaluator performs all measures with a given instrument throughout the study, if 
possible.  
 
8.  
INTERVENTIONS ADMINISTERED  
8.1  
INTERVENTION  
8.1.1  Study Product Description 
Niagen® is a commercially available form of nicotinamide riboside (NR) manufactured by ChromaDex, Inc. 
Niagen® is generally recognized as safe (FDA GRAS Notice No. 635) for use in a variety of media, including 
vitamin waters, protein shakes, and powdered beverages. Niagen® has five issued process and use patents in the 
United States and several others internationally.  
 
Chemical Structure of nicotinamide riboside: 
 
 
8.1.2  Drug and Placebo 
Chromadex Inc. will provide 250 mg capsules. Identical appearing capsules with only filler will be prepared as 
placebo. 
 

 
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8.1.3  Acquisition 
When the study intervention shipment arrives at the site, the person accepting the shipment must perform an 
inventory and fill out a supplement receipt log. The contents of the shipment must be counted, verified, and 
inspected for damage. Any damaged shipments will be documented. The study supplement will be picked up 
from MGH Clinical Trials Pharmacy on the same day it will be dispensed. Detailed logs will be kept recording 
quantity of supplement dispensed and study staff in charge of supplement transport and dispensing. 
8.2.  
Product Storage and Stability 
Niagen NR is found to be stable under ambient conditions of 25 °C and 60% relative humidity for 11 months in 
a solid, powdered form. 
 
8.3 
Dosage, Preparation and Administration of Study Intervention 
Niagen NR 1000 mg (four capsules) or PBO (four capsules) should be taken orally twice daily with food. The 
capsules should be swallowed whole.  
 
8.4 
Modification of Study Intervention for a Subject 
Dosing may be suspended at any time by the PI or designated licensed clinician sub-investigator. This will be 
documented along with the reason(s) and dates of adjustment in the CRF for each subject requiring this 
manipulation. The PI or designated licensed clinician Sub-Investigator may suspend the dosage of study dietary 
supplement or discontinue the study supplement for AEs thought to be related to the study supplement or for 
other reasons during the trial (the reason and dates of suspension or dose suspension must be documented in 
CRF). If the AE is mild or moderate, the dosage may be re-started after the event improves. If the AE is serious 
or life threatening and deemed to be definitely related to the dietary supplement, the study dietary supplement 
will be discontinued immediately. Study subjects must remain off the study dietary supplement permanently. 
Subjects may not resume study dietary supplement. All AEs will be followed to resolution. 
8.4.1  Dosage Discontinuation 
Reasons for discontinuation of study dietary supplement may include an AE or PI recommendation, protocol 
deviation, loss-to-follow-up, patient request, or death. All serious adverse events (SAEs) that occur in a subject 
who has discontinued early must be recorded and reported within 24-hours of awareness. Study subjects who 
discontinue study dietary supplement prematurely (early discontinuation from study) and decide not to remain 
in the study will be encouraged to return for an Early Termination Visit.  
8.5  
Assessment of Subject Compliance 
Subjects will be instructed to return empty and unused study dietary supplement containers at each clinic visit 
or the Early Discontinuation Visit. Research staff will review returned and unused study dietary supplement and 
log information into the reconciliation form to determine compliance. Non-compliance will be defined as taking 
less than 80% or more than 120% of study agent as determined by unused capsule counts. If a study subject is 
non-compliant with study dietary supplement, research staff should re-educate and train the subject in 
administration of study agent. If the subject’s non-compliance persists, it will be left up to the PI to determine 
whether the subject should be discontinued from the study.  
9. 
STATISTICAL ANALYSIS 
 
Descriptive statistics will be used to characterize the cohort’s demographic and clinical variables. We will 
conduct independent sample t-tests to examine between-group differences in demographic variables at baseline 
and analysis of variation (ANOVA) to test for between-group differences in treatment compliance for each 
study visit. 

 
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9.1 Primary analysis 
 
For all outcomes, we will perform intention-to-treat (ITT) analysis and mixed-effects model repeated measures 
(MMRM). Group (NR-NR vs. PBO-NR sequence), time, and group by time interactions will be included in the 
MMRM as fixed effects. The study’s outcomes will be the change score of ECog, RBANS, and TMT-B from 
baseline, and the change in NAD+ levels from baseline. We also will examine changes in the FSS, BAI, BDI, 
and PSQI scores. An unstructured covariance matrix will be used to account for the correlation of repeated 
measures within a participant. Age, sex, and education will be included in the models as covariates. 
 
9.1.2 Post-Hoc Analysis 
 
The sequential block design will provide the opportunity to examine the effects of NR using a larger sample 
size, as all participants will ultimately receive 10 weeks of NR (baseline to visit 2 for the NR-NR group; visits 
2–4 for the PBO-NR group). In addition to the standard MMRM analysis, we will combine the data from the 
two randomized groups and explore the pre-post changes in outcomes after 5 and 10 weeks of NR intake 
compared to baseline. To explore the potential impact of NAD+ levels on change in outcomes, we will perform 
linear regression analyses of change scores and NAD⁺ levels measured after 10 weeks, controlling for age, sex, 
education, and time since acute COVID-19 infection.  
 
9.1.3 Study Unblinding 
 
After database lock, the responsible statistician will request the treatment codes, the study will be unblinded, 
and the statistical analysis will be conducted.  
 
10. 
SAFETY AND ADVERSE EVENTS 
 
10.1  Potential Risks and Benefits 
At screening, we will collect standardized historical, symptomatic, physical exam, and laboratory parameters to 
identify health conditions that represent risks for participation in the study's procedures. 
 
10.1.1  Potential Risks 
Nicotinamide Riboside: Nicotinamide riboside is well-tolerated in patients, with few adverse events reported in 
a minority (3.3%) of patients16: 
• Mild nausea 
• Mild skin rash  
• Mild flushing/hot flashes 
• Mild leg cramps 
• Increased bruising  
 
None of the reported adverse events led to discontinuation of NR during its intervention period. 
 
Phlebotomy: The risks associated with having blood drawn, including the dried blood spot from the finger prick, 
include bruising and local discomfort. Rarely an infection may occur at this site, and if an infection does occur 
it will be treated by the study physician.  
 
Magnetic Resonance Imaging: MRI is a safe procedure for subjects who do not have metal implants or other 
contraindications. Individuals who have electrically, magnetically, or mechanically-activated implants (such as 

 
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heart pacemakers) or those who have clips on blood vessels in their brain will not be allowed to participate in 
the study due to risks associated with MRI scanning. The MRI will be operated in a manner accepted by the 
FDA. The protocol requires subjects to remain still within a relatively confined space during the scanning 
session, and the scanner makes loud knocking and beeping sounds as it takes images. While subjects with 
severe claustrophobia are excluded from the study, some subjects may find the physical confinement or noise 
uncomfortable. Every effort will be made to enhance each subject’s comfort level, and subjects will be given 
earplugs to reduce discomfort due to noise. If a subject notices any discomfort while in the MRI scanner, (s)he 
should notify the administrator immediately. If the discomfort cannot be stopped, the scanning session will be 
stopped. The MRI has the potential, during normal routine use, to cause localized warming of the skin and 
underlying tissues. Subjects should immediately inform the study staff if they experience discomfort due to 
warming of the skin and the procedure will be stopped. 
 
Neurocognitive testing: The neurocognitive tests that will be administered to assess mental performance may be 
stressful and potentially cause anxiety, fatigue, and frustration. In our prior experience with similar protocols, 
risks have occurred infrequently and very few subjects have terminated testing. However, testing will be 
discontinued immediately upon any request by the subject to do so. With the evaluation of individuals with 
cognitive complaints, there is always the potential for a subject to enter the study with subjective cognitive 
concerns and subsequently demonstrate a decline in cognitive performance throughout the course of the study to 
a level consistent with a diagnosis of mild cognitive impairment (MCI). If this occurs, a licensed clinician will 
meet with the subject and suggest that they see their primary care provider for further evaluation. 
 
Questionnaires: Questionnaires administered during the protocol may cause subjects to feel sad or upset about 
how residual symptoms of COVID-19 are affecting their quality of life. Study staff is experienced with such 
evaluations and sensitive to these issues. Any question can be omitted per the subject’s request.  
 
Wrist Actigraphy: The wrist actigraph, the Fitbit Charge 4, may cause some minor discomfort due to prolonged 
wearing, but the risk of such discomfort will be minimized by ensuring the wristband fits the subject properly 
(e.g. is not too tight or does not cause irritation). If the subject does experience discomfort, another wristband 
will be ordered to try to eliminate the discomfort.  
 
SARS-CoV-2 negative (PCR): The nasal swab that is required for this test may cause some discomfort or, in rare 
occasions, slight pain.  
 
Videoconferencing: Visits that take place via videoconferencing may allow research staff to learn more about 
the subject’s home and cohabitants than an office visit. The study team will use a secure Zoom 
videoconferencing platform and conduct the visit in a private location to ensure personal information about the 
subject is kept confidential. 
 
Other Risks: Reviewing health-related information might be stressful or make the subject feel uncomfortable. 
Subjects do not have to answer any questions they do not want to. In addition, there may be incidental medical 
findings as a result of the physical examination. The BDI inquires about suicidality. After the subject completes 
this instrument during the study visit, the coordinator will review the subjects’ answers to these questions. A 
response of 2 or 3 on Question 9 of the BDI, or any spontaneous expression of suicidality will result in 
emergent evaluation by a licensed clinician member of study staff for appropriate assessment and triage. If a 
participant provides a response of “1”, it will be considered non-urgent and a licensed clinician member of the 

 
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study staff will conduct an appropriate assessment and triage of the participant if necessary either in person, on 
the phone or virtually via the Zoom platform within 48 hours of being notified. 
 
 
10.1.2  Known Potential Benefits  
NR has been tested in a number of clinical trials in middle-aged and elderly patients and has shown to be well-
tolerated. If successful, this trial will further understand of the effects of NR on NAD+ levels, as well as of 
standard and personalized assessment of cognitive, neuropsychiatric, physical and everyday functioning, in 
individuals who were infected with COVID-19 and are currently experiencing residual and persisting 
symptoms. This trial is also assessing multiple biomarkers in concert with clinical outcomes, which will provide 
a detailed understanding of NR activity and provide a well-curated data set for the community of individuals 
who had COVID-19 to improve our understanding of the long-term effects of COVID-19.  
 
10.2 Data Security  
 
10.2.1 Laptop Computer 
 
Subjects will be provided a study-laptop during the visit to complete self-reported measures (i.e., BDI, BAI, 
PCL-C, ECog, BRIEF-A, PSQI, IPAQ, Fatigue Severity Scale) on REDCap and the online Continuous 
Performance Test (CPT). The laptop will be used only to complete the questionnaires on REDCap and the CPT. 
A study coordinator will always be present to address questions. No PHI or personally identifiable information 
will be entered into the system, so there are no additional data safety risks to the subject. The study laptop will 
be registered under the Principal Investigator and no identifying information will be required to sign in. There 
will be a password that will be available to the Principal Investigator and study coordinators, and not the 
participants. The computer has been encrypted using Bitlocker, per MGB’s policies. 
 
10.2.2 Mobile device 
Fitbit is a web-based application that require no PHI or personally identifiable information be entered into the 
system, so there are no additional data safety risks to the subject if they use their personal mobile device, tablet 
or computers. Subjects will sync Fitbit activity tracking through the Fitbit app downloaded to their personal 
mobile device, tablet or computers by logging into the application with their provided, deidentified account.  
 
10.2.3 Fitbit activity tracker  
A study coordinator will create a unique, deidentified email and password combination to create an account on 
Fitbit.com. To create an account, the following information will be required: first and last Name (a de-identified 
placeholder name], date of birth (January 01, year of birth), gender, height, and weight. The subject will be 
given the associated account information so that they are able to login, sync their device, and use the Fitbit 
dashboard. The subject will be notified that the researcher will also have full access to their account and will be 
able to freely view and download the subject’s data for research purposes. A copy of Fitbit’s Privacy Policy and 
Terms of Service will also be reviewed by the subject during the consenting process. By consenting to the 
study, the subject is also agreeing to these policies and terms.41 
 
After the subject has completed or if they are withdrawn from the study, their Fitbit account and all associated 
data will be deleted. However, prior to deleting the account, the de-identified study data will be downloaded and 
stored confidentially on Partner’s computers for study purposes.  
 
11. 
MONITORING AND QUALITY ASSURANCE 

 
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The adverse event (AE) definitions and reporting procedures provided in this protocol comply with all 
applicable United States Food and Drug Administration (FDA) regulations and International Conference on 
Harmonisation (ICH) guidelines. The PI will carefully monitor each subject throughout the study for possible 
adverse events. All AEs will be documented on CRFs designed specifically for this purpose. It will be important 
to report all AEs, whether serious or non-serious. 
 
11.1  Independent Monitoring of Source Data 
The PI will ultimately be responsible for the validity and integrity of the data collected at the MGH site, and for 
ensuring that the study is conducted in accordance with the IRB-approved protocol. After data is collected and 
recorded on forms, the study coordinator may input the data into the REDCap database. Entries will be 
reviewed for accuracy and completeness by a second study coordinator. Study coordinators will also review the 
subjects’ responses on REDcap to ensure that no data is missing. Finally, the PI or their designee (Co-I) will 
conduct monthly reviews to check that data in REDCap accurately reflects the data collected on the original 
data capture forms. The research team (PI, Co-I, research coordinators) will subsequently meet to discuss the 
results of this review, as well as case report forms and source documentation.  
 
All electronic documentation will be stored on password-protected devices in locked cabinets located in secured 
areas. Paper forms will be stored in locked cabinets located in secured areas. 
 
11.2  Safety Monitoring  
The adverse event (AE) definitions and reporting procedures provided in this protocol comply with all 
applicable United States Food and Drug Administration (FDA) regulations and International Conference on 
Harmonization (ICH) guidelines. The PI will carefully monitor each subject throughout the study for possible 
adverse events. All AEs will be documented on CRFs designed specifically for this purpose. It will be important 
to report all AEs, whether serious or non-serious. 
 
11.3  Definitions of AEs & SAEs 
 
11.3.1  Adverse Event 
An adverse event (AE) is any unfavorable and unintended sign (including a clinically significant abnormal 
laboratory finding, for example), symptom, or disease temporally associated with a study, use of a drug product 
or device, whether or not considered related to the drug product or device. 
 
Examples of adverse events include: new conditions, worsening of pre-existing conditions, clinically significant 
abnormal physical examination signs (i.e. skin rash, peripheral edema, etc.), or clinically significant abnormal 
test results (i.e. lab values or vital signs), with the exception of outcome measure results, which are not being 
recorded as adverse events in this trial (they are being collected, but analyzed separately). Stable chronic 
conditions (e.g. arthritis) that are present prior to the start of the study and do not worsen during the trial are NOT 
considered adverse events. Chronic conditions that occur more frequently (for intermittent conditions) or with 
greater severity are considered as worsened and therefore would be recorded as adverse events. Adverse events 
are generally detected in two ways: 
• Clinical → symptoms reported by the subject or signs detected on examination. 
• Ancillary Tests → abnormalities of vital signs, laboratory tests, and other diagnostic procedures 
(other than the outcome measures, the results of which are not being captured as AEs). 
 
If discernible at the time of completing the AE log, a specific disease or syndrome rather than individual associated 
signs and symptoms should be identified by the PI and recorded on the AE log. However, if an observed or 

 
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reported sign, symptom, or clinically significant laboratory anomaly is not considered by the PI to be a component 
of a specific disease or syndrome, then it should be recorded as a separate AE on the AE log. Clinically significant 
laboratory abnormalities, such as those that require intervention, are those that are identified as such by the PI. 
 
Subjects will be monitored for AEs from the time they sign consent until completion of their participation in the 
study (defined as death, consent withdrawal, loss to follow up, early study termination for other reasons, or 
following completion of the entire study). An unexpected adverse event is any adverse event, the specificity or 
severity of which is not consistent with the current Investigator’s Brochure. 
 
The study procedures and the well-being of all participants will be monitored closely by the MGH principal 
investigator and the Co-Investigators. Throughout the course of the study, constant feedback with the subject is 
maintained in order to assess comfort and safety and to minimize risks throughout the procedure. The above 
investigators will be responsible for determining if a subject should be removed from the study. Criteria for 
removal include the following: 1) if a subject is unwilling or unable to participate in study procedures 2) if the 
subject refuses to participate and consent, 3) if the subject acquires a medical condition that prohibits further 
participation, 4) if in the opinion of the MGH principal investigator, Dr. Edmarie Guzmán-Vélez, it is decided 
that it is not in the subject’s best interest to continue participation.  
 
Unanticipated problems including adverse events will be reported to the Partners Human Research Committee 
(PHRC) as described in the PHRC policy on Unanticipated Problems Involving Risks to Subjects or Others 
including adverse events. 
 
The Data Management team will be responsible for the development, execution, and supervision of plans, 
policies, programs, and practices that control, protect, deliver, and enhance the value of data and information 
assets. All data will be managed in compliance with applicable regulatory requirements. The study coordinator, 
under the supervision of the PI, will collect, transcribe, correct, and transmit the data onto source documents, 
Case Report Forms (CRFs), and/or other forms used to report, track, and record clinical research data. The study 
coordinator will be instructed to enter this information into the REDCap database. The REDCap platform provides 
password protection. An edit checking and data clarification process will be put in place to ensure accuracy of 
the data. Logic and range checks as well as more sophisticated rules may be built into the eCRFs to provide 
immediate error checking of the data entered. The system has the capability to automatically create electronic 
queries for forms that contain data that are out of range, out of window, missing, or not calculated correctly. The 
platform will have the ability to lock specific visits to prevent any modification of data once the visit is closed. 
Once this option is activated, every user will have Read-Only access to the data. The PI, Dr. Edmarie Guzmán-
Vélez, will be responsible for ensuring the accuracy, completeness, legibility, and timeliness of the data reported. 
 
11.3.2  Serious Adverse Events 
All adverse events will be reviewed by the MGH Principal Investigator, Dr. Edmarie Guzmán-Vélez, and will 
be reported to Partners IRB and to the Human Research Committee (HRC) in accordance with HRC Guidelines. 
A serious adverse event (SAE) is defined as an adverse event that meets any of the following criteria: 
1. Results in death. 
2. Is life threatening: that is, poses an immediate risk of death as the event occurs. 
o This serious criterion applies if the study subject, in the view of the PI, is at immediate risk of 
death from the AE as it occurs. It does not apply if an AE hypothetically might have caused 
death if it were more severe. 
3. Requires inpatient hospitalization or prolongation of existing hospitalization. 

 
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o Hospitalization for an elective procedure or a routinely scheduled treatment is not an SAE by this 
criterion because an elective or scheduled “procedure” or a “treatment” is not an untoward 
medical occurrence. 
4. Results in persistent or significant disability or incapacity. 
o This serious criterion applies if the “disability” caused by the reported AE results in a substantial 
disruption of the subject’s ability to carry out normal life functions. 
5. Results in congenital anomaly or birth defect in the offspring of the subject. 
6. Necessitates medical or surgical intervention to preclude permanent impairment of a body function 
or permanent damage to a body structure. 
7. Important medical events that may not result in death, are not life-threatening, or do not require 
hospitalization may also be considered SAEs when, based upon appropriate medical judgment, they 
may jeopardize the subject and may require medical or surgical intervention to prevent one of the 
outcomes listed in this definition. Examples of such medical events include blood dyscrasias or 
convulsions that do not result in inpatient hospitalization. 
 
An inpatient hospital admission in the absence of a precipitating, treatment-emergent, clinical adverse event 
may meet criteria for "seriousness" but is not an adverse experience and will therefore not be considered an 
SAE. An example of this would include a social admission (subject admitted for reasons other than medical, 
e.g., lives far from the hospital, has no place to sleep). 
 
The PI is responsible for classifying adverse events as serious or non-serious. 
 
11.4  Assessment and Recording of Adverse Events 
The PI will carefully monitor each subject throughout the study for possible AEs. All AEs will be documented 
on CRFs designed specifically for this purpose. All AEs will be collected and reported in the EDC system. 
 
11.4.1 Assessment of Adverse Events 
At each visit (including telephone visits), the subject will be asked if they had any problems or symptoms since 
their last visit in order to determine the occurrence of adverse events. If the subject reports an adverse event, the 
Investigator will probe further to determine: 
• Type of event 
• Date of onset and resolution (duration) 
• Severity (mild, moderate, severe) 
• Seriousness (does the event meet the above definition for an SAE) 
• Causality, relation to investigational protocol 
• Outcome 
 
11.4.2  Relatedness of Adverse Event to Investigational Protocol 
 
1. Not Related: 
Concomitant illness, accident, or event with no reasonable association with protocol. 
2. Unlikely: 
The reaction has little or no temporal sequence from administration of the investigational 
protocol, and/or a more likely alternative etiology exists. 
3. Possibly Related: 
The reaction follows a reasonably temporal sequence from administration of the 
investigational protocol and follows a known response pattern to the suspected 
investigational protocol; the reaction could have been produced by the investigational 
protocol or could have been produced by the subject’s clinical state or by other modes of 
therapy administered to the subject. 

 
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4. Probably Related: 
The reaction follows a reasonably temporal sequence from administration of investigational 
protocol; is confirmed by discontinuation of the investigational protocol or by re-challenge; 
and cannot be reasonably explained by the known characteristics of the subject’s clinical 
state. 
5. Definitely Related: 
The reaction follows a reasonable temporal sequence from administration of investigational 
protocol; that follows a known or expected response pattern to the investigational protocol; 
and that is confirmed by improvement on stopping of the investigational protocol, and 
reappearance of the reaction on repeated exposure. 
 
 
 
11.4.3  Recording of Adverse Events 
All clinical adverse events are recorded in the Adverse Event (AE) Log in the subject’s study binder. Study staff 
should fill out the AE Log and enter the AE information into the EDC system within 48 hours of learning of a 
new AE or receiving an update on an existing AE. 
 
Entries on the AE Log (and into the EDC) will include the following: name and severity of the event, the date of 
onset, the date of resolution, relationship to investigational product, action taken, and primary outcome of event. 
 
11.5  Adverse Events and Serious Adverse Events - Reportable Events 
The following are considered reportable events and must be reported via the EDC system within 24 hours of 
study staff being notified of the event. 
 
• All events that meet the above criteria for Serious Adverse Events 
 
11.6  Safety and Feasibility of Performing Experimental Visits at MGH-East (Charlestown Navy Yard)  
The entire study will be performed in MGH Building 149 in examination, testing and procedure rooms of the 
Neurology Service on the 2nd floor. If an emergency does occur, 911 will be called promptly, with the subject 
being managed by the study physician until paramedics arrive. This setup has been discussed with and approved 
by the nursing administration at the CNY Clinical Research Center. 
 
 
 

 
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