Sunscreens, which are commonly referred to as products containing sun protection factor (SPF), are classified as nonprescription or over-the-counter (OTC) drugs in the United States. This regulatory classification differs from that in many other countries, where sunscreens are primarily treated as cosmetic products. In the U.S., the active ingredients in sunscreen formulations must undergo rigorous evaluation to prove their safety for human use, in accordance with the safety and efficacy guidelines established by the Food and Drug Administration’s (FDA) OTC Monograph specific to sunscreen drug products.¹ Additionally, given their classification as drugs, these products may also face scrutiny regarding their environmental impact. For instance, the FDA announced on May 13, 2021, its intention to prepare an Environmental Impact Statement (EIS) concerning the active ingredients oxybenzone and octinoxate, as there are growing concerns about their potential adverse effects on coral reefs and marine biodiversity.^2,3

Despite the long-standing use of these products, concerns about both human safety and environmental sustainability continue to challenge the availability and efficacy of consumer SPF products. If the active ingredients that remain unverified by the FDA as generally regarded as safe and effective (GRASE) fail to demonstrate their safety through further research, the FDA may take the drastic step of banning them. Similarly, if these ingredients are deemed environmentally harmful and no viable alternatives exist, they could be restricted or prohibited in sunscreen formulations. Furthermore, other regulatory entities, including the United States Environmental Protection Agency (EPA), non-government organizations, legislators, and public sentiment, may complicate the commercialization of sunscreen products containing such controversial ingredients. The ramifications of these potential actions would undoubtedly resonate on a global scale.

Tracing the Evolution of Sunscreen Regulations: FDA’s Historical Impact

To understand the implications for human health, it is essential to review the historical development of the sunscreen OTC monograph. The FDA initiated its regulation of sunscreens in 1978 by issuing a draft monograph under an advanced notice of proposed rulemaking.⁴ Over the past four decades, this monograph has undergone numerous revisions but has yet to reach finalization. Notably, in 1999, the FDA published a final monograph that was partially stayed in 2001,⁵ followed by a final labeling effectiveness testing rule in 2011 that remains in effect today.⁶

Most recently, in February 2019, the FDA released a proposed “Tentative Final Monograph” (TFM) aimed at updating the requirements for sunscreen products.⁷ However, following the passage of the Coronavirus Aid, Relief, and Economic Security Act (CARES Act), the FDA published the Final Administrative Order (OTC000006) for Over-the-Counter Monograph M020 for Sunscreen Drug Products on September 24, 2021. This order was subsequently amended but largely mirrors the 2019 TFM, introducing new provisions for regulating OTC drug products as mandated by the CARES Act.^8,9 While this article will not delve into the transition from a monograph process to an “administrative order” (AO) process, it is important to note that the 2021 PO establishes new criteria for determining the GRASE status of nonprescription sunscreen drug product active ingredients. Once finalized, this order will replace the previously deemed order (i.e., the 1999 Stayed Final Monograph) and the 2011 final labeling and effectiveness rule. Significantly, the 2021 PO seeks new data on human safety for active ingredients previously classified as Category GRASE III, which lacked sufficient data for final classification.

The PO categorizes sunscreen active ingredients into three distinct groups based on their GRASE status. Only two ingredients, zinc oxide and titanium dioxide, are classified as GRASE Category I, indicating that they are recognized as safe and effective. These mineral or inorganic actives are among the 16 ingredients approved in the FDA’s sunscreen monograph. In contrast, aminobenzoic acid (PABA) and trolamine salicylate are deemed GRASE category II (not GRASE) and are thus prohibited for use. The largest group, GRASE Category III, encompasses substances for which insufficient data exists to determine safety. This group includes twelve “chemical” or “organic” sunscreens: cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone. These ingredients require further safety data before the FDA can categorize them as GRASE Category I.

Importantly, the FDA emphasizes that the request for additional data regarding the proposed Category III active ingredients does not imply that these substances are unsafe for use in sunscreens. Instead, the FDA is seeking further information to comprehensively evaluate their GRASE status, particularly in light of increased sunscreen usage and evolving insights regarding potential risks associated with these products since their initial evaluations.¹⁰

The FDA has also stated, acknowledging the recognized public health benefits associated with sunscreen use, that consumers should continue to apply sunscreen while also employing other sun protection strategies.¹¹ Therefore, there remains no justification for prohibiting the use of these ingredients in sunscreen products at this time.

The studies that the FDA has requested to evaluate the GRASE status of Category III active ingredients encompass both clinical and non-clinical research, including in vitro penetration tests along with additional necessary data. Required human clinical studies include assessments of dermal irritation and sensitization, dermal phototoxicity, as well as human absorption or pharmacokinetic (PK) studies, commonly known as maximum usage trials (MUsT studies). Furthermore, ancillary studies may include pediatric data, post-marketing safety analyses, and examinations of representative marketed products with an emphasis on dosage forms and inactive ingredients.

One of the most challenging aspects of this endeavor involves non-clinical studies, which raise concerns regarding animal testing, costs, and the time required. The industry is actively advocating for the FDA to accept weight-of-evidence approaches and novel alternative methods (NAMs) as substitutes for traditional animal studies. Meeting the complex testing requirements proposed by the FDA is a lengthy process, potentially spanning many years, with individual active ingredients requiring an estimated investment exceeding $12 million. Moreover, if MUsT studies indicate systemic absorption of actives greater than 0.5 ng/ml, further studies may be mandated, including toxicokinetics, systemic and dermal carcinogenicity, developmental and reproductive toxicity, and assessments of potential hormonal effects.

Preliminary MUsT studies conducted by the FDA have indicated systemic absorption levels surpassing 0.5 ng/ml, necessitating additional investigations. However, it is crucial to note that a MUsT result exceeding 0.5 ng/ml does not inherently suggest that the tested active is unsafe; the FDA has reiterated this point and emphasized that while the industry and other stakeholders develop further data, the public should continue utilizing sunscreens alongside other protective measures. Broad-spectrum sunscreens with SPF values of at least 15 remain vital components of a comprehensive skin-cancer prevention strategy.¹²

In response to the FDA’s call for additional data, the Personal Care Products Council (PCPC) Sunscreen Consortium has been established. The authors of this article are members of this consortium, which aims to uphold the safety and GRASE Category I status of seven of the twelve chemical active ingredients listed in the sunscreen monograph through a scientifically rigorous and timely approach agreed upon by the FDA. The seven active ingredients under support are octocrylene, avobenzone, octisalate, homosalate, octinoxate, oxybenzone, and ensulizole. These ingredients have been selected based on their significant use in consumer sunscreen formulations. The consortium’s objective is to ensure that adequate UV filters remain accessible, providing essential protection for the U.S. population against the harmful effects of UV exposure.

As previously mentioned, fulfilling these requirements is a complex and protracted process. Consequently, the FDA has indicated that if the industry demonstrates diligence and satisfactory progress for a specific ingredient, it may be willing to defer the issuance of a final AO regarding the status of sunscreens containing that ingredient.¹³

Evaluating the Environmental Impact of Sunscreen Ingredients

The other significant concern involves the potential environmental repercussions of sunscreen active ingredients. It is well-documented that since the early 1970s, the popularity of SPF products has surged dramatically, largely attributable to increasing consumer awareness of the health risks associated with sun exposure, including sunburn, premature skin aging, and skin cancer. This heightened awareness can be credited to efforts made by the industry, medical professionals, and various governmental and non-governmental organizations advocating for the public health benefits associated with sunscreen use. Consequently, the heightened usage of sunscreen actives has led to a proliferation of products—ranging from beach formulations to cosmetics and personal care items—that claim SPF protection. Despite the increased adoption of sunscreen, skin cancer remains the most prevalent cancer in the U.S., with over 9,000 individuals diagnosed daily and more than two people succumbing to the disease each day, according to www.skincancer.org. Sunburns significantly contribute to this issue; individuals who experience five or more sunburn episodes double their risk of developing melanoma. Alarmingly, it is estimated that one in five Americans will be diagnosed with skin cancer by age 70.^14,15,16

Portions of Hawaii have become a hotbed of sunscreen regulations.

As the use of sunscreen actives has escalated, scrutiny regarding their potential environmental impact, particularly on aquatic ecosystems, has intensified. Concerns have arisen regarding the effects of these actives on aquatic organisms. Monitoring studies have detected certain UV filters, widely utilized in significant quantities, in both freshwater and marine environments. Some research has implicated sunscreen usage in coral bleaching, prompting swift legislative actions in certain states to ban specific sunscreen ingredients, despite the lack of comprehensive scientific studies supporting these decisions. This is particularly evident in Hawaii.

As of January 1, 2021, a ban on oxybenzone and octocrylene took effect, and stricter regulations were enacted at the county level. Without substantial evidence, Maui County prohibited all non-mineral sunscreens, encompassing all twelve “chemical” sunscreens currently classified as GRASE Category III under the FDA sunscreen monograph. These ingredients are those that the FDA, along with other leading medical organizations, have indicated are effective in preventing sunburn, skin cancer, and premature skin aging when used as directed alongside other protective measures.¹⁷ The sun care industry is energetically working to generate the additional data that the FDA has requested to support the GRASE Category I status of these ingredients. However, the implications of such restrictions are troubling, as they could endanger Hawaiians who are vulnerable to the harmful effects of UV radiation and set a concerning precedent for consumers elsewhere. These county regulations came into effect in October 2022, with Hawaii County following suit with its ban implemented this month. For the purposes of these bans, “sunscreen” is defined as any product marketed for topical use to prevent sunburn, specifically beach products, and does not include products marketed as cosmetics for facial use.

Given the perplexing nature of these decisions made without concrete data, a more balanced understanding of the environmental impact of sunscreens has been proposed in a recent report by the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM). This report was commissioned by Congress under the guidance of the U.S. EPA due to concerns regarding the potential toxicity of sunscreens on various marine and freshwater organisms, particularly corals. It also addresses fears that consumers may opt to reduce their sunscreen usage rather than switch to UV filters deemed environmentally safe.¹⁸

Overall, the report reinforces the public health advantages associated with broad-spectrum sunscreen use and emphasizes the need for formulation flexibility to enhance consumer compliance. The report draws several conclusions and recommendations concerning the potential environmental effects of sunscreen:

There is currently a lack of sufficient, relevant, and reliable scientific data to perform realistic environmental risk assessments (ERAs). Consequently, there is inadequate scientific information to justify bans on sunscreen ingredients, and policymakers, regulators, and legislators should refrain from making decisions that impact consumer access to FDA-approved sunscreen UV filters until the scientific community reaches a well-informed consensus.

The EPA should conduct ecological risk assessments (ERAs) for all UV filters currently on the market, as well as for any new filters that may be introduced, to evaluate potential risks to aquatic ecosystems and their inhabitants.

The findings from the ERA should be communicated to the FDA for consideration in their oversight of UV filters.

The EPA, in collaboration with partner agencies (such as NOAA, FDA, NIH, CDC, NSF, DOI) and sunscreen formulators and UV filter manufacturers, should conduct, fund, or support research and share data regarding sources, fate processes, environmental concentrations, bioaccumulation studies, modes of action, and ecological and toxicity testing for UV filters both individually and as part of sunscreen formulations. Additionally, epidemiological risk modeling and behavioral studies related to sunscreen usage should be undertaken to better understand human health outcomes in relation to changing availability and usage.

Future research should comply with national or international standards where applicable, including the establishment of new national or international standards. Public access to and transparency in all data and research findings is of paramount importance.

Anticipating Future Regulations: The Path Forward for Sunscreen Safety

There is a strong expectation that the restrictive regulations enacted by Hawaii County will extend statewide. We remain hopeful that the recommendations outlined in the NASEM report, “Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health,” will foster a more scientifically-based foundation for future regulatory and legislative decisions at the state, local, and federal levels concerning this crucial public health product category.

As Michael Crichton aptly stated in his book, “State of Fear,” “the real question with any environmental action is, do the benefits outweigh the harm? Because there is always harm.”

In summary, sunscreen use faces significant challenges on two fronts, both of which could drastically reshape the industry landscape.

The necessity of sunscreen use cannot be overstated. Ultimately, we believe that a balance can be achieved between the impacts of sunscreen usage on the environment and human health, while also addressing the environmental concerns with the undeniable benefits to human health. Regardless of the challenges ahead, it is essential that we continue to advocate for the safe use of sunscreen products across the board.

References

1. 
   OTCMonograph_M020-SunscreenDrugProductsforOTCHumanUse09242021.pdf (fda.gov)
2. 
   Environmental Impact Statement (EIS) for Certain Sunscreen Drug Products, FDA
3. 
   https://www.federalregister.gov/documents/2021/05/13/2021-10091/intent-to-prepare-an-environmental-impact-statement-for-certain-sunscreen-drug-products-for
4. 
   Federal Register: 43 Fed. Reg. 37979 (Aug. 25, 1978). (loc.gov)
5. 
   01-32086.pdf (govinfo.gov)
6. 
   Federal Register: Labeling and Effectiveness Testing; Sunscreen Drug Products for Over-the-Counter Human Use
7. 
   FDA advances new proposed regulation to make sure that sunscreens are safe and effective, FDA
8. 
   FDA Takes Steps Aimed at Improving Quality, Safety and Efficacy of Sunscreens, FDA
9. 
   OTC Monographs@FDA
10. 
    Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen, FDA
11. 
    FDA advances new proposed regulation to make sure that sunscreens are safe and effective, FDA
12. 
    Shedding New Light on Sunscreen Absorption, FDA
13. 
    An update on sunscreen requirements: The deemed final order and the proposed order, FDA
14. 
    https://www.skincancer.org/skin-cancer-information/skin-cancer-facts/#:~:text=1%20in%205%20Americans%20will,for%20melanoma%20is%2099%20percent
15. 
    https://www.aad.org/media/stats-skin-cancer
16. 
    https://www.cdc.gov/cancer/skin/index.htm
17. 
    https://www.fda.gov/consumers/consumer-updates/tips-stay-safe-sun-sunscreen-sunglasses
18. 
    https://nap.nationalacademies.org/catalog/26381/review-of-fate-exposure-and-effects-of-sunscreens-in-aquatic-environments-and-implications-for-sunscreen-usage-and-human-health