Nonprescription Sunscreen Drug 
Products  Safety and 
Effectiveness Data 
 
 
Guidance for Industry 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research (CDER) 
 
November 2016 
OTC 
   
Nonprescription Sunscreen Drug 
Products  Safety and 
Effectiveness Data 
 
 
Guidance for Industry 
 
 
 
 
Additional copies are available from: 
 
 
Office of Communications, Division of Drug Information 
Center for Drug Evaluation and Research 
Food and Drug Administration 
10001 New Hampshire Ave., Hillandale Bldg., 4th Floor  
Silver Spring, MD  20993-0002  
Phone:  855-543-3784 or 301-796-3400; Fax:  301-431-6353 
Email:  druginfo@fda.hhs.gov 
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research (CDER) 
 
November 2016 
OTC 
   
TABLE OF CONTENTS   
 
 
I.  INTRODUCTION............................................................................................................. 1 
II.  PHARMACEUTICAL QUALITY/MANUFACTURING INFORMATION ............. 3 
III.  SAFETY DATA NEEDED TO ESTABLISH THAT AN OTC SUNSCREEN 
ACTIVE INGREDIENT IS GRASE ............................................................................... 4 
A.  Clinical Safety Testing ................................................................................................................... 5 
   1. Human Dermal Safety Studies ......................................................................................................... 5 
a.  Human irritation and sensitization studies .................................................................................. 6 
b. Human photosafety studies ......................................................................................................... 7 
2. Human Absorption Studies/Maximal Usage Trial ........................................................................... 7 
3. Pediatric Considerations ................................................................................................................. 9 
B.  Nonclinical Safety Testing ........................................................................................................... 10 
1. Carcinogenicity Studies:  Dermal and Systemic ............................................................................ 10 
2. Developmental and Reproductive Toxicity Studies ........................................................................ 11 
3. Toxicokinetics ................................................................................................................................ 11 
C.  Postmarketing Safety Data .......................................................................................................... 12 
IV.  EFFECTIVENESS TESTING ....................................................................................... 13 
V.  ANTICIPATED FINAL FORMULATION TESTING .............................................. 14 
 
  Contains Nonbinding Recommendations 
Nonprescription Sunscreen Drug Products   
Safety and Effectiveness Data 
1
Guidance for Industry  
 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or Agency) on 
this topic.  It does not establish any rights for any person and is not binding on FDA or the public.  You 
can use an alternative approach if it satisfies the requirements of the applicable statutes and regulations.  
To discuss an alternative approach, contact the FDA office responsible for this guidance as listed on the 
title page. 
 
 
 
 
I.  INTRODUCTION  
 
This guidance addresses the current thinking of the Food and Drug Administrations (FDA or 
Agency) about the safety and effectiveness data needed to determine whether a nonprescription 
(also referred to as an over-the-counter (OTC)) sunscreen active ingredient,2 or combination of 
active ingredients, evaluated under the Sunscreen Innovation Act (SIA) (21 U.S.C. Ch. 9, Sub. 5 
Part I, enacted November 26, 2014) is generally recognized as safe and effective (GRASE) and 
not misbranded when used under specified conditions.   
 
FDA is issuing this guidance in partial implementation of the SIA.  Among other things, the SIA 
supplemented FDAs existing regulation for adding a new active ingredient or other condition to 
an OTC drug monograph3 with new procedures and review time lines for determining whether or 
not a nonprescription sunscreen active ingredient is GRASE and not misbranded when used 
under the conditions specified in a final sunscreen order .4  A critical step in that process is 
FDAs review of safety and effectiveness data submitted by the person requesting the GRASE 
                                                 
1 This guidance has been prepared by the Division of Nonprescription Drug Products in the Center for Drug 
Evaluation and Research (CDER) at the Food and Drug Administration.  
 
2 As defined in the SIA,  the term sunscreen active ingredient refers to an active ingredient that is intended for 
application to the skin of humans for purposes of absorbing, reflecting, or scattering ultraviolet radiation (see section 
586(10) of the Federal Food, Drug, and Cosmetic Act (FD&C Act) (21 U.S.C. 360fff(10)). 
 
3 FDAs existing regulation sets out the time and extent application procedure by which a new active ingredient or 
other condition (e.g., dosage form, dosage strength, or route of administration) can be considered for inclusion in the 
OTC drug monograph system (21 CFR 330.14).  
4 See section 586(4) of the FD&C Act (21 U.S.C. 360fff-1) (definition of GRASE determination); section 586A of 
the FD&C Act (21 U.S.C. 360fff-1) (submission of a new request for GRASE determination); section 586B of the 
FD&C Act (21 U.S.C. 360fff-2) (preliminary filing review, eligibility determination, and request for submission of 
safety and effectiveness data); and section 586C of the FD&C Act (21 U.S.C. 360fff-3) (GRASE determination and 
issuance of proposed and final sunscreen orders). 
 
1  Contains Nonbinding Recommendations 
determination (sponsor).5  If FDA determines that the active ingredient in question is GRASE 
and not misbranded for use in nonprescription sunscreens, it will issue a final sunscreen order 
setting out the conditions that sunscreen products containing the active ingredient must satisfy to 
be marketed without an approved new drug application (NDA).6  Sunscreen products that satisfy 
those conditions and other requirements for nonprescription drugs may be marketed immediately 
upon issuance of the final sunscreen order, for as long as that order remains in effect.  Any future 
rulemaking to amend the OTC sunscreen drug monograph must include the active ingredient 
found GRASE in the final order.7   
 
The SIA also directed FDA to issue guidance on the data a nonprescription sunscreen active 
ingredient would need to meet the safety and efficacy standard for a GRASE determination.8  
The recommendations in this guidance will help sponsors identify and obtain the safety and 
effectiveness data needed to show that a sunscreen active ingredient is GRASE for use in 
nonprescription sunscreens, as a single active ingredient and/or as part of a combination of active 
ingredients.  Unlike the review of sunscreen products under the new drug approval process,9 for 
which premarketing testing focuses on individual product formulations, the GRASE review for 
active ingredients takes into account that the ingredient, if found GRASE, may be included in a 
variety of formulations that will be marketed without product-specific review and approval.   
 
The recommendations in this guidance are designed to ensure that FDAs GRASE 
determinations for OTC sunscreen active ingredients under the SIA are consistent, up to date, 
and appropriately reflect current scientific knowledge and patterns of nonprescription sunscreen 
use by consumers.  The recommendations reflect FDAs scientific expertise, existing technical 
guidance, experience from reviewing safety and efficacy data submitted for GRASE review of 
sunscreen active ingredients under current OTC drug regulations, and input from and 
concurrence by outside scientific experts.  This guidance also addresses FDAs current thinking 
about an approach to safety-related final formulation testing that it anticipates adopting in the 
future. 
 
                                                 
5 See section 586C of the FD&C Act.  FDA will also consider other relevant public data submitted by other parties 
or otherwise available.   
 
6 See section 586C of the FD&C Act generally for detailed procedures.    
 
7 See section 586C(e)(1)(A) of the FD&C Act (effect of final sunscreen order for sunscreen active ingredient(s) 
found to be GRASE) and section 586C(e)(3) of the FD&C Act (any future amendments of the OTC sunscreen 
monograph must include any nonprescription sunscreen active ingredient(s) that is or are subject to an effective final 
sunscreen order that determined it or them to be GRASE and would set forth the conditions of use).  
 
8 See section 586D(a)(1)(B) of the FD&C Act (21 U.S.C. 360fff-4(a)(1)(B)); see also section 586D(a)(1)(A)(ii) of 
the FD&C Act.  The SIA also requires FDA to issue three other guidances on procedural matters relating to 
nonprescription sunscreen active ingredients:  (1) format and content of data submissions (section 586D(a)(1)(A)(i)); 
(2) process for withdrawing requests for a GRASE determination (section 586D(a)(1)(A)(iii)); and (3) process by 
which FDA will carry out section 586C(c) of the FD&C Act regarding advisory committee meetings (section 
586D(a)(1)(A)(iv)). 
 
9 This process is described in 21 CFR part 314. 
2  Contains Nonbinding Recommendations 
FDAs specific recommendations on the data and information needed to support a positive 
GRASE determination under the SIA are detailed in sections II (pharmaceutical 
quality/manufacturing information), III (safety data), and IV (effectiveness data).  Section V 
presents FDAs current thinking on an approach to safety testing of final sunscreen formulations 
that it anticipates adopting in the future. 
 
Although sunscreen products are typically formulated with two or more active ingredients, the 
recommendations in sections II through IV generally contemplate that testing will be performed 
using formulations including one active ingredient FDA anticipates that these data would also 
generally be sufficient to assess whether, and under what conditions, that active ingredient is 
GRASE for use as part of a combination of sunscreen active ingredients.  In some situations, 
additional data and testing beyond what is recommended in this guidance may be needed to 
support a positive GRASE determination and to establish the associated conditions for a 
particular active ingredient.  The following are examples in which additional data may be 
needed:  
 
  Data suggest that there may be a safety or efficacy concern with a particular combination 
of active ingredients or active and inactive ingredients  
 
  Information indicates that an active ingredient is unstable when exposed to sunlight and 
suggests that the active ingredient may need to be combined with a photostabilizer to be 
safe or effective    
 
Other situations may occur in which additional data are needed (see, e.g., section III for some 
additional examples).  Sponsors are encouraged to discuss with FDA any questions about 
whether additional data may be needed for a particular active ingredient. 
 
In general, FDAs guidance documents do not establish legally enforceable responsibilities.  
Instead, guidances describe the Agencys current thinking on a topic and should be viewed only 
as recommendations, unless specific regulatory or statutory requirements are cited.  The use of 
the word should in Agency guidances means that something is suggested or recommended, but 
not required. 
 
 
II.  PHARMACEUTICAL QUALITY/MANUFACTURING INFORMATION 
 
FDA needs information that sufficiently characterizes the identity of each sunscreen active 
ingredient for FDA reviewers to determine how, if at all, the safety and efficacy studies 
submitted for review are relevant to the ingredient for which GRASE determination is sought.10  
This information would also be needed to appropriately characterize the active ingredient in the 
                                                 
10 For example, if key studies were conducted using a related but different compound, or using a combination of 
active ingredients whose individual contributions to the observed results were not examined, those studies may have 
little relevance to a GRASE determination for the sunscreen active ingredient identified by the requested 
quality/manufacturing data.  
 
3  Contains Nonbinding Recommendations 
final sunscreen order.  Sponsors should provide the compendial status of the ingredient, 
including reference to a United States Pharmacopeia National Formulary monograph.  Sponsors 
should also provide any known chemical and/or manufacturing characteristics of the active 
ingredient that may be relevant to FDAs GRASE evaluation and to the establishment of the 
conditions of any resulting final sunscreen order.11  Such information should include known 
interactions with other sunscreen active ingredient(s) or commonly used sunscreen vehicle 
component(s) and particle size information for micronized or nanoscale active ingredients.  In 
addition, sponsors should describe any aspects of formulation that are needed to ensure stability, 
or other characteristics of the active ingredient that are needed to establish conditions under 
which it is GRASE for use in sunscreens. 
 
 
III.  SAFETY DATA  
 
FDAs OTC drug regulations identify both the general types of safety information that sponsors 
should submit as evidence that an OTC drug is GRASE for use as labeled ( 330.10(a)(2) (21 
CFR 330.10(a)(2))) and the standard by which such safety information is to be judged ( 
330.10(a)(4)(i)).  When applying these regulations to a given active ingredient, FDA uses its 
scientific expertise to determine what constitutes adequate tests by methods reasonably 
applicable to show the drug is safe under the prescribed, recommended, or suggested conditions 
of use.12   
 
FDA recognizes the contribution that broad spectrum sunscreens with a sun protection factor 
(SPF) value of 15 or higher can make to decrease the risk of skin cancer and early skin aging 
caused by the sun if used as directed with other sun protection measures.  To protect the public 
health, it is also important for FDA to balance the potential benefits of these sunscreen products 
to consumers against their potential risks.  Providing an adequate safety margin13 for OTC 
sunscreen active ingredients and finished sunscreen products is a key element of FDAs risk 
assessment.  When determining the specific testing and other data needed to adequately 
demonstrate that an OTC sunscreen active ingredient is safe, FDA considers both the 
circumstances under which OTC sunscreen products are intended to be used by consumers and 
current scientific knowledge and assessment technology. 
 
                                                 
11 The determination of whether a sunscreen active ingredient is GRASE and not misbranded also requires the 
Agency to describe the conditions under which any future product incorporating that sunscreen active ingredient will 
be GRASE and not misbranded (see, e.g., section 586C(e) of the FD&C Act; see also section V of this document). 
 
12  330.10(a)(4)(i). 
 
13 For drugs with a known potential for adverse effects based on animal data, the anticipated level of risk for humans 
may be quantified using a safety margin calculation.  A safety margin calculation takes the highest animal no 
observed adverse effect level and estimates a maximum safe level of exposure for humans.  One caveat to the safety 
margin calculation is that animal studies do not always predict effects in humans, and the actual threshold for an 
effect in humans may be different (higher or lower) than in the species tested.  The human sensitivity to a drug is 
often unknown.  To account for this, the predicted safe exposure level in humans that is reflected in the safety 
margin is well below where toxicities were seen in animals. 
 
4  Contains Nonbinding Recommendations 
To ensure full discussion of the kinds of data needed to address sunscreen safety, FDA held a 2-
day meeting of the Nonprescription Drugs Advisory Committee on September 4-5, 2014, at 
which FDA presented much of the same approach that is recommended in this guidance.  There 
was consensus among the independent scientific experts on the committee that FDAs 
framework was a good starting point.14  This guidance takes into consideration the 
recommendations FDA received from this committee meeting. 
 
FDAs current approach for evaluating the clinical safety of potential nonprescription sunscreen 
active ingredients is based on our current scientific understanding regarding the safety evaluation 
of topical drug products for chronic use and thus is generally consistent with the safety data 
requirements that would apply to a new drug application (NDA) for a chronic-use cutaneous 
drug product (i.e., topical safety studies (irritation, sensitization, and photosafety), bioavailability 
(absorption), and evaluation of adverse events observed in clinical studies).15  In addition, an 
evaluation of adverse events reported during the commercial marketing of sunscreen products 
containing the ingredient  as well as other postmarketing safety information is also relevant to 
FDA safety evaluation. 
 
FDAs current approach to the nonclinical safety evaluation of these active ingredients takes into 
account that only active ingredients that have been marketed to a material extent and for a 
material time in OTC sunscreen products are eligible under the SIA for a GRASE 
determination.16  In contrast to nonclinical data requirements for a chronic-use cutaneous drug 
product NDA, which include comprehensive nonclinical pharmacology and toxicology safety 
testing, the approach to nonclinical safety testing in this guidance is largely focused on potential 
long-term adverse effects or effects not otherwise readily detected from human use (i.e., 
carcinogenicity and reproductive toxicity).  Please note, though, that testing beyond what is 
recommended in this guidance may be needed for active ingredients for which data suggest a 
concern about other long-term effects, such as hormonal disruption.  
 
The following sections describe the specific safety data that FDA needs to determine whether an 
active ingredient is GRASE for use in sunscreens.  However, FDA will consider alternative 
scientifically based approaches for addressing a particular data need.  Sponsors are encouraged to 
discuss alternative proposals with FDA before initiating studies.   
 
A.  Clinical Safety Testing  
 
1.  Human Dermal Safety Studies 
 
                                                 
14 See the minutes of the FDA September 4-5, 2014, meeting of the Nonprescription Drugs Advisory Committee 
(2014 NDAC Minutes) at 
http://www.fda.gov/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/NonprescriptionDrugsAdvisoryCom
mittee/ucm380890.htm. 
 
15 Chronic use is defined as continuous or intermittent use of a product for at least 6 months during a lifetime. 
 
16 See section 586B(a)(2) of the FD&C Act. 
 
5  Contains Nonbinding Recommendations 
Human dermal safety studies for topical products in which exposure to light after application is 
anticipated generally consist of two sets of studiesthose conducted without specific exposure 
to light and those conducted to assess reactions after ultraviolet exposure (photosafety studies).17  
These study sets usually consist of dermal irritation patch testing, dermal sensitization patch 
testing, dermal phototoxicity testing, and dermal photoallergenicity testing. 
 
Because marketed sunscreen products typically contain a combination of active ingredients and 
because brand name product formulations frequently change, it is difficult for FDA to determine 
causal links between individual active ingredients and reported irritation and hypersensitivity 
adverse events associated with a particular product.  Therefore, FDA generally expects to use 
data from human irritation studies, human skin sensitization studies, and human photosafety 
studies, in conjunction with postmarketing adverse event data, to inform GRASE determinations 
and labeling.  Nonetheless, in some cases, depending on the rigor of available postmarketing 
safety information, it may be reasonable for sponsors to omit human irritation studies, human 
skin sensitization studies, and/or human photosafety studies.  For example, if FDA concludes 
that there is a positive risk-benefit for a sunscreen active ingredient but that it is known to be a 
sensitizer, it may be possible to develop safety labeling to address this risk without data 
generated in the human dermal safety studies described below.  Sponsors who believe there is a 
scientific rationale that may preclude the need for some or all of the described studies are urged 
to contact FDA before initiating studies.  
 
a.  Human irritation and sensitization studies 
 
Studies of skin irritation and sensitization that use the repeat insult patch test or other relevant 
tests are recommended elements in FDAs safety evaluation of topical drug products that, like 
sunscreens, are applied to the skin repeatedly over long periods of time.  These tests, which are 
designed to detect the potential of topical drug products for local dermatologic events with fewer 
subjects than might be observed in larger clinical trials, often involve applying product more 
frequently and/or for longer durations than the proposed clinical dosing of those drug products.  
In dermal irritation studies, a test substance is applied to a small pad (patch) and affixed to the 
test subjects skin, usually on the back, to determine whether the ingredient causes direct skin 
toxicity.  Dermal sensitization studies are conducted similarly but are designed to detect 
immunologically mediated reactions, which require prior exposure to the allergen.   
 
Nonprescription sunscreen active ingredients, when found to be GRASE, may be used in 
numerous, as yet unknown, product formulations.  Therefore, FDA recommends that cumulative 
irritation studies evaluate (1) the proposed sunscreen active ingredient at the highest 
concentration for which a GRASE determination is sought, in an appropriate vehicle; (2) the 
vehicle alone; (3) a negative control; and (4) a positive control.  The evaluation should include 
scoring of erythema, edema, and a papular response or skin erosion. 
 
                                                 
17 See the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use 
(ICH) guidance for industry S10 Photosafety Evaluation of Pharmaceuticals.  We update guidances periodically.  To 
make sure you have the most recent version of a guidance, check the FDA Drugs guidance Web page at 
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm.   
6  Contains Nonbinding Recommendations 
Skin sensitization studies, conducted to detect immunologically mediated reactions, should be 
conducted in the following three phases:   
 
(1) The induction phase (three weekly applications for 3 weeks) 
  
(2) The rest phase (no product application for 10 to 14 days)  
 
(3) The challenge phase (patch applications to new sites for 48 hours with a confirmatory 
rechallenge to exclude false positives)  
  
Although FDA recommends separate dermal irritation and sensitization studies, irritation and 
sensitization studies can be combined in the same study as long as a sufficient number of 
subjects are included for sensitization evaluation.  
 
b.  Human photosafety studies 
 
Topically applied dermatologic drug products should be tested for photosafety if they absorb 
light in the ultraviolet A, ultraviolet B, or visible spectra.  FDA recommends that photosafety 
evaluations of sunscreen active ingredients that absorb light consist of skin photoallergenicity 
and skin phototoxicity testing.  Photoallergy is an immunologically mediated reaction to a 
chemical, initiated by the formation of photoproducts (e.g., protein adducts) following a 
photochemical reaction.  Similar to dermal sensitivity testing described above, photoallergy tests 
use an induction/rest/challenge/rechallenge multiphase design to assess erythema, edema, and 
vesiculation.  Phototoxicity (or photoirritation) is an acute light-induced tissue response to a 
photoreactive chemical.  Phototoxicity testing typically includes a test patch, a vehicle patch, and 
a sham patch application for 24 hours, followed by ultraviolet light exposure of the test area.  A 
second set of patch application areas not irradiated with light serves as a control.   
 
FDA recommends that photosafety studies of sunscreen active ingredients that absorb light be 
conducted using (1) the active ingredient at the highest concentration for which a GRASE 
determination is sought in an appropriate vehicle, (2) the vehicle alone, and (3) a negative 
control.   
 
2.  Human Absorption Studies/Maximal Usage Trial 
 
Because nonprescription sunscreens are topically applied, a critical safety consideration is 
whether dermal application results in skin penetration and systemic exposure to the active 
ingredient and, if so, to what extent.  This information helps identify potential safety concerns 
and helps determine whether an adequate safety margin exists for an active sunscreen ingredient 
to be included in the OTC sunscreen monograph.   
 
The principal barrier to cutaneous drug product penetration is the multilayered, lipid-rich stratum 
corneum.  The passage of any drug product through this layer is influenced by many factors, 
including the drug products physicochemical features, molecular weight, and 
vehicle/formulation properties.  Vehicle/formulation properties are particularly important 
because the choice of vehicle can markedly affect the permeation potential of a drug product.  
7  Contains Nonbinding Recommendations 
Effects can range from simple hydration of the stratum corneum by occlusive 
vehicles/formulations to direct permeation enhancement by solvent effects on the lipids in the 
stratum corneum.  Products absorbed through the skin have the potential to cause systemic 
adverse effects, affecting the safety assessment.  Because sunscreens are intended to work at the 
skins surface, systemic absorption may also lower efficacy, affecting the efficacy assessment.   
 
Since the mid-1990s, topical product NDAs have included a Maximal Usage Trial (MUsT) as 
part of the clinical pharmacology/bioavailability assessment.  A MUsT is designed to capture the 
effect of maximal use on absorption into the blood with standard pharmacokinetic assessments 
(e.g., C , T , area under the curve, half-life, clearance, and volume of distribution).  For a 
max max
topical product NDA, the MUsT is usually conducted in subjects with the disease of interest, 
where disrupted skin is a feature.  In situations where disrupted skin is not a feature of the 
disease or the topical drug product is intended for prevention of disease (e.g., sunscreens), the 
MUsT for a topical product NDA may be conducted in subjects with healthy, intact skin.  The 
MUsT for a topical product NDA is conducted with the specific product formulation for which 
approval is sought, applied at the upper limit of surface area involvement that is studied in the 
phase 3 clinical trials and is proposed for labeling.  That is to say, if the proposed labeling 
permits the product to be used on up to 30 percent of body surface area, then the coverage 
evaluated in the MUsT would be 30 percent of body surface area.18,19  
 
FDA recommends that SIA sponsors of sunscreen active ingredients provide data from a MUsT 
to support an adequate assessment of safety.20  Because a determination that an active sunscreen 
product is GRASE would permit its use in a variety of finished sunscreen products, FDA 
recommends that the MUsT to support the GRASE determination.be conducted under maximal 
use conditions employing a minimum of four formulations containing the proposed sunscreen 
active ingredient as the only active ingredient.  These formulations should be prepared using 
vehicle/formulation systems that are appropriate for sunscreen topical products (e.g., they are 
deployable or spreadable) and that are expected to produce the highest in vivo absorption.  
Justification for the formulations chosen, including results of in vitro testing using a human 
cadaver skin permeation system (e.g., static or flow-through cells),21 should be included in the 
study protocol.  The protocol should contain sufficient detail for others to reproduce the 
formulations and manufacturing processes.   
 
                                                 
18 Bashaw, ED, DC Tran, CG Shukla, et al., January 2015, Maximal Usage Trial:  An Overview of the Design of 
Systemic Bioavailability Trial for Topical Dermatological Products, Ther Innov Regul Sci, 49(1):108-115. available 
at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663190/. 
 
19 See the FDA draft guidance for industry Acne Vulgaris:  Developing Drugs for Treatment.  When final, this 
guidance will represent the FDAs current thinking on this topic. 
 
20 See the response to Discussion Question 1 in the 2014 NDAC Minutes, supra note 15, at 6 (expressing the need 
for human maximal use studies in all cases). 
 
21 Bronaugh, RL and RF Stewart, January 1985, Methods for In Vitro Percutaneous Absorption Studies IV:  The 
Flow-Through Diffusion Cell, J Pharm Sci, 74(1):64-67. 
 
8  Contains Nonbinding Recommendations 
FDA anticipates that the use of multiple formulations will help identify the overall absorption 
potential of the sunscreen active ingredient of interest.  The MUsT for a potential monograph 
sunscreen active ingredient should be conducted in subjects with healthy, intact skin22 at the 
highest concentration of the ingredient for which a GRASE determination is sought and 
eligibility under the SIA has been established.  Because sunscreens are  recommended for use on 
all exposed skin, the exposed area should include at least 75 percent of the body surface area.  
Data from the formulation that produces the highest in vivo absorption would then be used to 
determine the safety margin.  
 
The assay used in the MUsT should be properly validated according to current good laboratory 
practices (21 CFR part 58) and should be consistent with the FDA guidance for industry entitled 
Bioanalytical Method Validation.  The assays limit of quantitation-limit of detection should be 
sufficiently low to allow a signal-to-noise ratio that ensures confidence in detection of a derived 
concentration of 0.5 nanogram (ng)/milliliter (mL).   
 
An important consideration for designing a MUsT is that it should include testing for a duration 
that allows for the attainment of steady state levels to ensure that maximum penetration of the 
ingredient has taken place and to optimize the chances of the ingredient being detected.  Thus, 
for sunscreen ingredients, FDA expects that single application studies would be inadequate.  
Because the subjects in a MUsT represent an enriched dataset in the upper range of exposures, 
FDA currently recommends collection of safety-related data (such as vital signs or adverse skin 
events) from the studys regularly scheduled physical examinations.  Sponsors are strongly 
encouraged to discuss their MUsT protocol with FDA before beginning the trial. 
 
As discussed further in section V, if the sunscreen active ingredient is determined to be GRASE, 
the final order must set out the conditions under which any future product incorporating that 
sunscreen active ingredient will be GRASE and not misbranded. As such a condition, FDA is 
considering certain final formulation testing. FDA anticipates that  the formulation that produces 
the highest in vivo absorption in the MUsT may be appropriate to designate as a standard control 
formulation for future in vitro human cadaver skin permeation system testing (e.g., static or 
flow-through cells) of each final sunscreen formulation that includes that active ingredient. In 
such a case, if in vitro permeation of the sunscreen active ingredient in the final product 
formulation were equal to or less than the value from in vitro testing of the standard control 
formulation (that was shown by the MUsT to have the highest degree of systemic absorption), 
FDA anticipates that the safety margin calculated would be considered adequate to support the 
safety of the finished formulation. 
 
3.  Pediatric Considerations 
 
Young children have a larger ratio of skin surface to body volume compared to adults, which can 
increase a childs systemic exposure to topically applied drug products.  In addition, growing 
children have greater potential to experience deleterious developmental effects from drug 
exposure.  If the calculated safety margin for a proposed monograph active ingredient (based on 
                                                 
22 As discussed infra, the MUsT should be conducted in subjects with healthy, intact skin because sunscreens are 
intended for prevention rather than treatment.  
9  Contains Nonbinding Recommendations 
nonclinical results and human MUsTs) supports a GRASE determination, but the safety margin 
is relatively small, FDA will exercise its scientific judgment to determine if either a sunscreen 
active ingredient MUsT in young children or other studies are warranted to ensure that the safety 
margin for marketed products containing the ingredient is within an acceptable range for this 
population.  
 
B.  Nonclinical Safety Testing 
 
1.  Carcinogenicity Studies:  Dermal and Systemic 
 
FDA generally recommends that carcinogenicity studies be conducted for any pharmaceutical 
either with an expected continuous clinical use of at least 6 months or with an expected clinical 
use of a minimum of 6 months in an intermittent manner.23  The animal carcinogenicity studies 
help characterize the potential tumor risks associated with a sunscreen active ingredient by 
identifying any observed tumors by type, the level of exposure at which tumors occur, and the 
highest level of exposure at which no adverse effects occur, referred to as the no observed 
adverse effect level (NOAEL).  The NOAEL would be used in determining the safety margin for 
human exposure to sunscreens containing the active ingredient.  In addition to detecting 
carcinogenic potential, carcinogenicity studies in animals can help identify other systemic or 
organ toxicities that may be associated with the proposed ingredient. 
 
To support the safety of OTC sunscreen active ingredients, FDA recommends that sponsors 
conduct a dermal carcinogenicity study that involves applying the product to the skin of mice or 
rats for 2 years.  FDA also considers it important to study the effects of systemic exposure when 
human bioavailability data show that dermal application of a particular formulation could result 
in skin penetration and systemic exposure.  After the active ingredient is marketed in 
nonprescription sunscreens, that active ingredient is likely to be used in a wide variety of product 
formulations that might alter its skin penetration.  Therefore, FDA also generally recommends 
that sponsors conduct a second carcinogenicity study by a route that produces systemic 
exposure.24  This study can be a 2-year study or a shorter (usually 6 months) alternative 
carcinogenicity model, but either study should be conducted in a species different from that used 
in the dermal carcinogenicity study.  FDA notes that the absence of a carcinogenicity signal from 
                                                 
23 See the ICH guidance for industry The Need for Long-Term Rodent Carcinogenicity Studies of Pharmaceuticals.  
 
24 FDA expects that a systemic carcinogenicity study would not be needed to support a GRASE determination for a 
sunscreen active ingredient if both (1) an adequately conducted human pharmacokinetic MUsT results in a steady 
state blood level less than 0.5 ng/mL and (2) an adequately conducted toxicology program does not reveal any other 
safety signals for the ingredient or for any known structurally similar compound indicating the potential for adverse 
effects at lower levels.  The threshold value of 0.5 ng/mL is based on the principle that that level would approximate 
the highest plasma level below which the carcinogenic risk of any unknown compound would be less than 1 in 
100,000 after a single dose.  This threshold value is consistent with the Threshold of Toxicological Concern concept, 
which  was applied to impurities in the ICH guidance for industry M7 Assessment and Control of DNA Reactive 
(Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk.  FDA expects that the 0.5 ng/mL 
concentration will be sufficiently above the assays limit of quantitation-limit of detection to allow a signal-to-noise 
ratio that assures confidence in either the derived concentrations (in the case of exaggerated values) or lack of 
concentrations. 
 
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an alternative transgenic carcinogenicity study (e.g., TgRasH2 mouse) would likely support the 
safety of a sunscreen active ingredient.  However, if a carcinogenicity signal was observed in 
such a study, the study would not support the safety of a sunscreen active ingredient because 
there is no basis for calculating a safety margin with this study.25  All carcinogenicity studies
regardless of routeshould assess a full panel of tissues.26   
 
2.  Developmental and Reproductive Toxicity Studies  
 
FDA recommends that sponsors conduct developmental and reproductive toxicity (DART) 
studies to evaluate the potential effects that exposure to the sunscreen active ingredient may have 
on developing offspring throughout gestation and postnatally until sexual maturation, as well as 
on the reproductive competence of sexually mature male and female animals.27  Gestational and 
neonatal stages of development may be particularly sensitive to active ingredients with hormonal 
activity (endocrine disruption).  For this reason, FDA recommends that these studies include 
assessments of endpoints such as vaginal patency, preputial separation, anogenital distance, and 
nipple retention, which can be incorporated into traditional DART study designs to assess 
potential hormonal effects on the developing offspring.  FDA also recommends that sponsors 
perform behavioral assessments (e.g., assessing mating behavior) of offspring, which may detect 
neuroendocrine effects.28 
 
3.  Toxicokinetics29 
 
FDA recommends that sponsors collect animal toxicokinetic data for sunscreen active 
ingredients because these data provide an important bridge between toxic levels seen in animal 
studies and any potential human adverse events associated with systemic exposure to the 
sunscreens active ingredient (see section III.A.2).  Toxicokinetic measurements are usually 
obtained during the course of ongoing nonclinical toxicity studies, such as in carcinogenicity or 
DART studies, rather than through separate studies.   
 
                                                 
25 Jacobs, AC and PC Brown, July 2015, Regulatory Forum Opinion Piece:  Transgenic/Alternative Carcinogenicity 
Assays:  A Retrospective Review of Studies Submitted to CDER/FDA 1997-2014, Toxicol Pathol, 43(5):605-10. 
 
26 FDA recommends submitting the carcinogenicity study protocol(s) for review by CDER's Executive 
Carcinogenicity Assessment Committee prior to initiating the studies.  For further guidance regarding 
carcinogenicity studies, see the FDA guidance for industry Carcinogenicity Study Protocol Submissions. 
 
27 See the ICH guidance for industry S5A Detection of Toxicity to Reproduction for Medicinal Products.  FDA 
expects that studies to assess both fertility and prenatal or postnatal toxicity may not be needed if both (1) an 
adequately conducted human MUsT shows absorption that results in a steady state blood level less than 0.5 ng/mL 
and (2) there are no signals in an adequately conducted toxicology program indicating that the ingredient or any 
known structurally similar compound interacts with related pathways, such as endocrine function or signaling 
pathways related to growth and development.  FDA would continue to recommend that effects on embryofetal 
development be assessed. 
 
28 See the FDA guidance for industry Nonclinical Evaluation of Endocrine-Related Drug Toxicity. 
 
29 See the ICH guidance for industry S3A Toxicokinetics:  The Assessment of Systemic Exposure in Toxicity Studies. 
 
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C.  Postmarketing Safety Data 
 
In addition to the active ingredient safety data already described, FDAs GRASE evaluation also 
takes into consideration available information about serious adverse drug experiences and known 
or expected adverse effects associated with commercially marketed products that contain the 
active ingredient(s) under consideration.  FDA specifically requests that sponsors provide the 
following information:  
  
  A summary of all potentially associated serious adverse drug experiences. 
 
  A summary of all available potentially associated nonserious adverse drug experiences. 
 
  A summary of expected or frequently reported side effects, whether serious or 
nonserious. 
 
  Copies of all available reports of potentially associated serious adverse drug experiences.  
Each report submitted should be in the form of an individual case safety report as 
described in 21 CFR 314.80 and refer only to an individual consumer or to a single 
attached publication. 
 
  Any available safety information from studies of safety and effectiveness in humans. 
 
  Relevant medical literature describing associated adverse events. 
 
English translations should be provided for all foreign language materials. 
 
For products marketed outside the United States, submissions should also state whether each 
countrys system allows for adverse event reporting and, if so, how each countrys system 
identifies and collects the adverse event information.30  If adverse event information is not 
available from all countries where the active ingredient has been marketed in OTC sunscreen 
products, the sponsor should provide an explanation for the missing data.  It is important to note, 
however, that even when countries have an adverse event reporting system that includes 
sunscreen products, underreporting is a significant limitation of any system that depends on 
spontaneous reports.  
 
Many factors can influence whether an adverse event is reported, including whether a possible 
relationship between the event and an ingredient or product is recognized by consumers or health 
care providers.  For example, adverse events that occur many years after a causal drug exposure 
may not be recognized as being related to that exposure, especially if the background rate of 
those adverse events is high (e.g., a common cancer or a developmental problem).  Thus, an 
absence of reports does not necessarily equate to an absence of adverse events.  Despite the 
limitations of adverse event reporting, FDA considers postmarketing data to be relevant both to 
                                                 
30 See, e.g., 21 CFR 330.14(c)(2)(v). 
 
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the overall GRASE assessment of OTC sunscreen active ingredients and to labeling 
considerations because these data may reveal safety signals not otherwise observed in clinical or 
nonclinical testing. 
 
 
IV.  EFFECTIVENESS DATA 
 
FDAs OTC drug regulations generally identify both the types of effectiveness information that 
sponsors should submit as evidence that a drug product containing an active ingredient or other 
OTC drug condition could be GRASE for use as labeled ( 330.10(a)(2)) and the standard by 
which effectiveness is to be judged, which requires controlled clinical investigations to support 
effectiveness ( 330.10(a)(4)(ii)).  
 
When applying these regulations to each potential sunscreen active ingredient, FDA requests that 
sponsors provide evidence from at least two adequate and well-controlled SPF studies showing 
that the active ingredient effectively prevents sunburn, because sunburn prevention is the 
minimum indication for an OTC sunscreen product.  Two adequate and well-controlled SPF 
studies of the active ingredient at a lower concentration than the maximum requested should be 
conducted according to established standards.31  These SPF studies should demonstrate that the 
selected concentration provides an SPF value of 2 or higher.   
 
The current standard procedure for SPF testing is described in  201.327(i) (21 CFR 
201.327(i)).32  Any new SPF tests for a particular ingredient should be performed as described in 
these regulations, using a test formulation containing the ingredient as the only active ingredient 
to identify its contribution to the overall SPF test results.  These tests should also include a 
vehicle control arm to rule out any contribution the vehicle may have had on the SPF test results.  
Finally, as described in  201.327(i), an SPF standard formulation comparator arm should be 
another component of the study design. 
 
Current sunscreen testing and labeling regulations in  201.327(j) also specify a broad spectrum 
testing procedure, which provides an in vitro measurement of a sunscreen products ability to 
protect against both ultraviolet A and ultraviolet B radiation.  Broad spectrum protection is often 
the result of the combined contribution of multiple active ingredients in a final sunscreen 
formulation; thus, FDA does not expect that a sunscreen active ingredient would undergo broad 
spectrum effectiveness testing to establish its effectiveness for a GRASE determination for use in 
OTC sunscreen products.  
 
Under  201.327, the determination of whether an individual sunscreen product subject to that 
regulation may be labeled as broad spectrum (and therefore bear the additional claims related to 
                                                 
31 FDA expects that the upper bound of any concentration of the active ingredient ultimately established would be 
governed by the safety data, as well as by efficacy. 
 
32 Although this SPF testing procedure is used primarily for final formulation testing of finished products marketed 
without approved NDAs, it is equally applicable for determining whether or not a sunscreen active ingredient is 
generally recognized as effective as part of the overall GRASE determination. 
 
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that labeling) is made on a product-specific basis, applying the standard testing methods set forth 
in those regulations.33  If a sunscreen active ingredient evaluated under the SIA is established to 
be GRASE for use in nonprescription sunscreens, the final sunscreen order can address broad 
spectrum testing and related labeling conditions for final sunscreen formulations containing that 
ingredient. 
 
 
V.  ANTICIPATED FINAL FORMULATION TESTING  
 
The preceding sections of this guidance have concentrated on recommendations for safety and 
effectiveness data needed to support FDAs determination that a sunscreen active ingredient is 
GRASE for use in sunscreens.  FDAs determination that an active ingredient is GRASE will be 
made in the form of a final sunscreen order that will set out the conditions under which any 
future product incorporating that sunscreen active ingredient will be GRASE and not misbranded 
(see section I).34  As noted in section III.A.2, variations among individual sunscreen products
and in particular, aspects of the lotion or other vehicle in which active ingredients are delivered 
 can affect their absorption and thus their safety and effectiveness.   
 
To address the variability among sunscreen formulations, FDA currently requires final 
formulation testing of nonprescription sunscreen products to ensure their effectivenessnamely, 
testing for SPF value as well as broad spectrum protection and water resistance where those 
attributes are claimed in product labels.35  FDA anticipates that final sunscreen orders issued for 
sunscreen active ingredients determined to be GRASE under the SIA will also include conditions 
requiring final formulation testing to ensure the safety of all sunscreen formulations permitted by 
the order.   
 
The discussion that follows provides FDAs current thinking about such final formulation safety 
testing, to be conducted in the future.  Note that FDA has not yet determined what particular 
final formulation testing, if any, will be specified in future final sunscreen orders for any given 
sunscreen active ingredient.   Such requirements will be established on an ingredient-specific 
basis, taking into consideration the data recommended to be supplied under other parts of this 
guidance to support a GRASE determination (e.g., whether any safety signals are detected in 
well-conducted nonclinical carcinogenicity and DART studies).  Interested parties can provide 
relevant information and comments regarding final formulation testing for an individual 
sunscreen active ingredient as part of the GRASE determination process for that ingredient. 
 
                                                 
33 These standard testing methods are also described in the guidance for industry Labeling and Effectiveness Testing:  
Sunscreen Drug Products for Over-The-Counter Human UseSmall Entity Compliance Guide. 
 
34 See section 586D(e) of the FD&C Act. 
 
35 See  201.327 for the current requirements for OTC sunscreens containing the active ingredients already 
evaluated under the monograph system.  OTC sunscreens marketed under NDAs provide similar information in their 
product-specific applications to substantiate their labeling. 
 
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FDAs current thinking is that final formulation safety testing of nonprescription sunscreens 
would not generally call for an in vivo study.  Instead, FDA expects that the conditions of 
marketing specified for sunscreen active ingredients in final sunscreen orders would require 
manufacturers to perform in vitro permeation testing before marketing each new formulation.36  
Consistent with the approach for final formulation efficacy testing required by  201.327, FDA 
anticipates that it would not review the results of the in vitro final formulation safety testing 
before product marketing.  Rather, FDA expects that final sunscreen orders would require 
manufacturers to maintain records of this testing; these records would be available to FDA.  
 
First, as mentioned in section III.A.2, FDA anticipates establishing a standard control 
formulation for each sunscreen active ingredient, to be used in the final formulation testing of 
products containing that ingredient.  The standard control formulation would be the formulation 
that produces the highest in vivo absorption in the MUsT.  The results of in vitro human cadaver 
skin testing using this control formulation can then be used to bridge to a corresponding level of 
in vivo absorption from the MUsT used to establish the safety margin for the GRASE ingredient. 
 
Then, FDA anticipates that final formulation testing would be conducted for each formulation 
intended to be marketed, using a specified human cadaver skin diffusion cell, either Franz (static) 
or Bronaugh (flow-through).  The results of the in vitro permeation testing of the new 
formulation would be evaluated in light of the absorption found in the standard control 
formulation for the active ingredient it contains.  If a final sunscreen formulation contains a 
combination of sunscreen active ingredients, FDA anticipates that the final formulation would be 
tested against the standard control formulations for each of the sunscreen active ingredients it 
contains.  A standard control formulation might not be specified for a particular sunscreen active 
ingredient if FDA determines that the ingredient is unlikely to be absorbed through the skin.   
 
If the in vitro permeation of each sunscreen active ingredient in the final formulated product is 
equal to or less than the value obtained from in vitro testing of the standard control formulation 
for that active ingredient, FDA anticipates that the products safety margin would be considered 
to fall within the parameters judged to be GRASE and thus to support marketing of the new 
formulation.  However, if the in vitro permeation of the active ingredient from the specific final 
formulation is greater than the value obtained from in vitro permeation testing of the standard 
control formulation for that active ingredient, FDA anticipates that the formulation would not be 
considered GRASE.  In that situation, the sponsor would have the option to either (1) 
reformulate the product and conduct in vitro testing to establish that the reformulated product 
satisfies the final formulation testing condition set forth in the order; or (2) seek NDA approval 
for the new formulation. 
                                                 
36 FDA recommends this approach as an alternative to final in vivo (MUsT) testing of final product formulations, 
which was recommended by the Nonprescription Drugs Advisory Committee (see the response to Discussion 
Question 2 in the 2014 NDAC Minutes, supra note 15, at 7).  
15