Effects of Daily Supplementation of 5-HTP on Body Composition, a Randomized Investigation
Phase: NA
Conditions: Body Composition
Sponsor: Nova Southeastern University

Study Protocol and Statistical Analysis Plan 
 
Study Title: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
 
Protocol Version 2 
Document Date: 01/03/22 
Protocol ID# 102 
 
Principal Investigators: 
Jose Antonio PhD FNSCA FISSN CSCS 
Cassandra Evans MS RD  
Nova Southeastern University 
 
 
 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
 
 
5 HTP Study Protocol Table of Contents 
 
Protocol Signature 
3 
Abbreviations  
3 
Abstract 
4 
Background 
4 
Study Objectives 
5 
Study Methods 
5 
Missing Data 
6 
Statistical Analysis 
6 
Summary of Data 
6 
FDA Reporting 
6 
 
 
 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
PROTOCOL SIGNATURE  
I confirm that I have read this protocol, and I will conduct the study as outlined herein and 
according to the ethical principles stated in the latest version of the Declaration of Helsinki, and 
the applicable laws and regulations of the federal government. I will promptly submit the 
protocol to the IRB for review and approval. I understand that any modification made during the 
course of the study must first be approved by the IRB prior to implementation except when such 
modification is made to remove an immediate hazard to the subject. 
 
List of Abbreviations 
 
Abbreviation or Term 
Definition/Explanation 
5-HTP 
5-Hydroxytryptophan 
PLA 
Placebo 
SSRIs 
Selective serotonin reuptake inhibitors 
 
 
 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
Abstract 
The purpose of this investigation was to determine the effects of supplementing with 100 mg daily 
of 5-Hydroxytryptophan (5-HTP) on indices of body composition in exercise-trained men and 
women.  
Specific Aims:  
Aim 1: Anthropometric measurements will be collected to determine if 5-HTP supplementation 
can induce changes in body composition.  
Aim 2: Self-reported dietary intake will be tracked using MyFitnessPal to determine if daily 5-
HTP supplementation influences eating behaviors. 
Aim 3:  
Methods: Subjects were randomized into a treatment (100 mg 5-HTP daily; CLEANMOOD™) or 
a placebo (maltodextrin). Body composition was assessed pre- and post-treatment after eight 
weeks via a multi-frequency bioelectrical impedance device (InBody® 270). Subjects were 
instructed to not change their training or eating habits; moreover, they were instructed to track 
their diet ~2-3 days per week using a mobile app (MyFitnessPal).  
Hypothesis: 
Compared to placebo, daily supplementation with 5-HTP will result in changes in body 
composition.  
 
Background 
5-Hydroxytryptophan (5-HTP) is an amino acid and intermediate metabolite of L-tryptophan. 5-
HTP crosses the blood-brain barrier, stimulating serotonin (5-hydroxytryptamine) receptors in the 
central nervous system.[1, 2] Increasing serotonin levels may lead to changes in eating behavior, 
such as reduced calorie intake and increased satiety.[3, 4] When consumed orally, 70% of 5-HTP 
is delivered to the bloodstream. Once absorbed, 5HTP supplementation increases serotonin 
production and other brain chemicals such as melatonin, endorphins, dopamine, and 
norepinephrine. Supplementing with 5-HTP is linked to appetite suppression, improved sleep 
quality and decreased feelings of anxiety and depression. [2, 3, 5-8]  5-HTP has been posited to be 
an effective weight-loss aide due to its anorexigenic effects; however, little data exists and virtually 
all investigations have studied overweight or obese subjects. Cangiano et al. showed that 5-HTP 
supplementation influenced energy intake in non-insulin dependent diabetic subjects.  Subjects 
receiving 5-HTP consumed less energy via decreased consumption of fats and carbohydrates 
resulting in weight loss.[5] Another study observed the effects of a 5-HTP containing supplement 
on body composition in overweight females. Subjects were instructed to reduce their energy intake 
moderately. Following 4-weeks of 5-HTP supplementation, significant reductions in BMI, arm 
circumference and hip circumference were observed. Increased feelings of satiety were greater in 
the supplement group when compared to placebo.[8] Ioannou and Williams examined the effects 
of 5-HTP intake on brain activity as it relates to food sensitivity in healthy individuals.[6] Subjects 
were randomly assigned to a 5-HTP or vitamin C supplement group.  This investigation discovered 
that 5-HTP intake influences areas of the brain related to macronutrient selection and increased 
awareness of the body’s internal physiological needs. The vitamin C group was more responsive 
to high caloric and fatty foods compared to the 5-HTP group.  This study suggests that 5-HTP 
intake can influence macronutrient intake as well as modulate eating behaviors. Presently, there 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
are no studies that have assessed the effects of 5-HTP in exercise-trained individuals. Therefore, 
the purpose of this investigation was to determine the effects of supplementing with 100 mg daily 
of 5-hydroxytryptophan (5-HTP) on indices of body composition in exercise-trained men and 
women. 
 
Study Objectives 
 Primary Objective 
To assess changed in body composition.  
Secondary objective  
To assess any changes in dietary intake. 
 
 
Study Methods 
Study Design 
This study followed a placebo (PLA)-controlled, double-blind and parallel-group design. 
Study population 
61 physically active, healthy, adults (>18) were volunteered for this study. 
Inclusion-Exclusion Criteria  
Inclusion Criteria: 
• 
Healthy or free of disease 
• 
Minimum of 1 year of regular physical activity. Regular physical activity is defined by a 
minimum of 150 minutes of aerobic activity or performing muscle-strengthening 
exercises at least 2 days a week. 
Exclusion Criteria: 
• 
Physically inactive 
• 
Regularly used sleep aids of any kind 
• 
Currently taking selective serotonin reuptake inhibitors (SSRIs) and/or 5-HTP containing 
supplements. 
Discontinuation or Withdrawal from Study 
The reasons a subject may discontinue or be withdrawn from the study include, but are not 
limited to, adverse events, non-compliance or personal request to no longer participate in study. 
Randomization and Blinding 
All subjects and investigators were blinded. The supplement and placebo were in similar in 
capsule appearance and were packed in unmarked packaging. The research team were unaware 
of the subject assignments until completion of the entire study. 
Intervention and Placebo 
The dietary supplement (100 mg of 5-hydroxytryptophan; CLEANMOOD™) was provided by 
NURA™ (Irvine, California USA). CLEANMOOD is an organic 5-Hydroxytryptophan (5-HTP) 
ingredient. The placebo consisted of maltodextrin in a capsule. Subjects were instructed to 
consume one capsule daily at their convenience for 8 weeks. 
Data Collection Schedule 
Subjects were instructed to arrive at the laboratory after a 3-hour fast. All pre and post-testing 
occurred between 1200 and 1700 hours. 
 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
Study Visit 
Pre/Baseline  
Post  
Informed Consent 
x 
 
InBody 
x 
x 
Vitals 
x 
x 
Supplement Instruction 
x 
 
Connect MyFitnessPal 
account 
x 
 
Asses dietary intake via 
MyFitnessPal 
x 
x 
Asses Compliance (number 
of pills remaining) 
 
x 
 
Missing Data 
Thirteen subjects were excluded from the data set due to lack of compliance or failure to 
complete the study. 
 
Statistical Analysis 
All data is presented as the mean+SD. GraphPad (Prism 8) software was used for statistical 
analyses. A t-test was used to determine if statistically significant differences (p<0.05) existed 
between the delta scores of the treatment versus the placebo. 
 
Summary of Study Data 
Demographic and Baseline 
The characteristics of the treatment and placebo groups were as follows (age: 5-HTP 30+10, 
placebo 29+11; height cm: 5-HTP 171.0+8.7, placebo 167.7+15.0; body mass kg: 72.9+13.4, 
placebo 69.1+11.9). Subjects in this investigation were exercise-trained (years of training: 5-HTP 
14+10, placebo 16+11; hours of resistance training per week: 5-HTP 5+2, placebo 5+3; hours of 
aerobic training per week: 5+4, placebo 6+5). 
 
FDA Annual Reporting  
This study is not a FDA regulated drug or device, therefore there are no annual reporting 
requirements to the FDA.  
 
Clinical Trial Data Bank 
The study will be registered on http://clinicaltrials.gov and the NCI CTRP (Clinical Trials 
Reporting Program) by the Clinical Trials Office. 
 
 
References  
 
1. 
Birdsall, T.C., 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med 
Rev, 1998. 3(4): p. 271-80. 
2. 
Maffei, M.E., 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, 

Protocol name: Effects of Daily Supplementation of 5-HTP on Body Composition, a 
Randomized Investigation   
Protocol Version 2 
Document Date: 01/03/2022  
Principal Investigators: Jose Antonio PhD FNSCA FISSN CSCS and Cassandra Evans MS RD  
 
Biotechnology, Physiology and Toxicology. Int J Mol Sci, 2020. 22(1). 
3. 
Halford, J.C., et al., Serotonergic anti-obesity agents: past experience and future prospects. 
Drugs, 2011. 71(17): p. 2247-55. 
4. 
Yabut, J.M., et al., Emerging Roles for Serotonin in Regulating Metabolism: New 
Implications for an Ancient Molecule. Endocr Rev, 2019. 40(4): p. 1092-1107. 
5. 
Cangiano, C., et al., Effects of oral 5-hydroxy-tryptophan on energy intake and 
macronutrient selection in non-insulin dependent diabetic patients. Int J Obes Relat Metab 
Disord, 1998. 22(7): p. 648-54. 
6. 
Ioannou, S. and A.L. Williams, Preliminary fMRI findings concerning the influence of 5-
HTP on food selection. Brain Behav, 2017. 7(1): p. e00594. 
7. 
Jacobsen, J.P.R., et al., Adjunctive 5-Hydroxytryptophan Slow-Release for Treatment-
Resistant Depression: Clinical and Preclinical Rationale. Trends Pharmacol Sci, 2016. 
37(11): p. 933-944. 
8. 
Rondanelli, M., et al., Relationship between the absorption of 5-hydroxytryptophan from 
an integrated diet, by means of Griffonia simplicifolia extract, and the effect on satiety in 
overweight females after oral spray administration. Eat Weight Disord, 2012. 17(1): p. 
e22-8.