Foluso M. Akin-Ige and Samiul Amin, University of Miami04.21.23
In the past century, consumers have become increasingly aware of the dangers linked with excessive exposure to UV radiation such as premature aging, sunburn and skin cancer. Consequently, this has led to a rapid rise in the demand for sun care products, necessitating extensive usage of organic UV filters as active components in sun care formulations due to their UV-blocking properties. However, several research studies continue to present growing evidence of the potential harmful effects of these UV filters on the environment, as well as human health.1
As a result of this shift in consumer preferences, many product formats are being re-engineered to achieve better safety and sustainability profiles; sun care products are no exception. Sunscreens are mostly formulated as emulsions (creams and lotions) to be delivered as leave-on products and are typically designed by incorporating UV filters into a stable emulsion base. The process of re-formulation for sunscreens is not without its unique limitations as formulators must simultaneously grapple with the re-design of the sunscreen emulsion base to be both stable and sustainable using less traditional emulsifiers whose properties are not fully understood, while ensuring that the blend of UV filters incorporated into the formulation are compatible with the emulsion base and are deemed safe for use by the appropriate regulating body due to constantly changing regulatory guidelines. Thus, re-formulation, which is relatively less complex and better understood with products like cleansers and wash-off products, becomes more challenging in the case of sun care products.
Table 1: US FDA Approved UV Filters4
Since 2019, the cosmetics industry has experienced heightened regulatory action against UV agents in sun care products. The island of Bonaire, in Netherlands, voted to ban the sale of reef killing sun protection on its shores in 2021.5 Thailand banned sunscreens containing oxybenzone, octinoxate and 4-methylbenzylidene camphor, from all its marine national parks in 2021.6 More recently, an amended regulation regarding a limit to the use of the UV filters benzophenone-3 and octocrylene in cosmetics was published by the European commission, citing endocrine-disrupting properties as reported by the Scientific Committee on Consumer Safety (SCSS).7
Similarly, a new ordinance banning the use of all sunscreens containing organic UV filters and stipulating the use of only mineral sunscreens (containing inorganic filters) went into effect in Maui County of the state of Hawaii, as of October 2022.8 These are instances that establish the regulation and/or banning of UV filters as a global phenomenon alongside the looming possibility of more restrictions being placed on sunscreen filters without replacements, as evidenced by the fact that under the 2019 FDA Proposed Tentative Final Sunscreen Monograph, aminobenzoic acid (PABA) and trolamine salicylate have been deemed as not GRASE due to safety issues and will likely be dropped from the list of US approved UV filters in the near future while no single new UV filter has been approved for use in cosmetics since avobenzone in 1996 thus, constituting a ‘pain point’ in the formulation of eco-friendly sunscreens.9,10
Typically, organic UV filters are transferred to the environment through two major pathways- directly through wash-off from skin and clothing by humans during recreational activities, and indirectly through industrial discharges, wastewater effluents, runoffs, and domestic uses. It is pertinent to note that coastal tourism plays a major role in the direct transfer of these UV filters into the environment, as it has been reported that the increase in tourist population and concentration of these UV-blocking compounds in the water of these areas are correlated. While the photostability of UV filters is a desirable quality in sunscreen formulations, it is less desirable once released into aquatic environments, where they are likely to form toxic by-products, through direct or indirect photolysis.11,12 Chlorinated by-products formed via photolysis in chlorous environments; e.g., pool water, pose a serious threat to human health. Furthermore, most organic UV filters tend to bioaccumulate in biota due to their high lipophilicity and poor biodegradability, severely impacting the survival, development, and reproduction of these organisms.11
The widespread use of the inorganic filters—titanium dioxide and zinc oxide in ‘reef safe sunscreens’—is supported by a general belief that they are safer. Of the 16 currently approved active ingredients for sunscreen in the US, only these two are recognized as GRASE (generally regarded as safe and effective) lending credence to this belief. However, the use of a substance may only be termed “safe for the environment,” based on its intrinsic hazard profile and the results of an environmental risk assessment (ERA).11
Studies have shown that inorganic filters are equally as toxic to biota as their organic counterparts, especially in nanoparticle forms, leading to respiratory difficulties in fish and some other aquatic organisms. In one study, manufactured nano-sized titanium dioxide led to physiological damage on the trout species, Oncorhynchus mykiss. Titanium dioxide has also been proven to cause oxidative stress, increase of breathing frequency, bewildered swimming and changes in superoxide dismutase and catalase activity, while zinc oxide has been shown to cause tissue ulceration in larvae. It must be noted that a problem with mineral sunscreens containing a combination of these inorganic filters is the negative sensory feel they impart, which becomes more pronounced and unacceptable in demographics with darker skin tones. Not only do these filters present a challenge to the consumer, but they are also notably difficult to formulate with as well; hence, incorporating these filters in their nanoparticulate forms into sunscreens for ease of formulation and enhanced performance was developed to mitigate this issue.11 However, with concerns being raised about the harmful environmental impact of zinc oxide and titanium dioxide nanoparticles, there is a growing need for safer and more sustainable alternatives.11
It is also possible for humans to be exposed to organic UV filters that have been washed off while swimming in pool water, via ingestion and dermal absorption.1 The phenomenon of biomagnification which occurs when contaminants that accumulate in low-trophic level species are later detected in their predators, is closely associated with bioaccumulation in marine organisms hence, seafood consumption is an avenue through which sunscreen agents are ingested by humans.11 The presence of UV filters in human breast milk, urine and plasma has been described in various studies and in one study, it was reported that more than 75% of analyzed human milk samples were contaminated with UV filters, indicating a possible exposure of breastfeeding infants to the sunscreen compounds.1 Indoor air is another source of human exposure to many semi-volatile organic chemicals, including organic UV filters. In a study, benzophenone-3 was found in 81 indoor air samples collected from New York. This compound has also been detected in other places within the US, such as in the greater Boston area and in California, as well as places outside the US e.g China.1
In 2022, a published patent by the University of Utah and the University of Princeton disclosed a composition utilizing oxidized amino acids obtained from protein sources as active ingredients in sunscreens.14 These amino acids exhibit excellent UV-protective absorption and energy dissipation properties, are naturally derived from compounds called kyurenines and can be easily broken down by living organisms, making them an ideal choice for replacing xenobiotic sunscreens, which are currently a cause for environmental concern.14
In response to the problem of skin whitening often presented by mineral screening agents, a patent was published in 2022 detailing a non-whitening composition incorporating an acrylic polymer and a dextrin ester which reportedly yield stable compositions with highly desirable qualities such as high SPF, no whitening effect and non-greasy feeling on skin.13 In May 2023 L’Oréal unveiled a new UV filtering technology, UVMune 400, designed to provide highly efficient shielding against ultra-long UVA radiation, which constitutes 30% of sun rays that previously went unfiltered.15 Another novel technology looking into the development of potentially non-irritating, sustainable and stable nanoemulsion sunscreen compositions is currently being worked on by researchers at the University of Miami.
On the regulatory front, DSM is making continuous efforts to obtain FDA approval for Bemotrizinol (BEMT), a highly photostable broad-spectrum filter that offers excellent UVA and UVB protection, even at low concentrations. Since 2016, DSM has been providing BEMT under the trade name of Parsol Shield as a UV light absorber for use in sunscreens and personal care cosmetic products. It is an easy-to-use ingredient that works well with both organic and inorganic UV filters. Despite being used globally since 1999, BEMT is not yet approved for use under the OTC Sunscreen Monograph. Obtaining its approval would be immensely beneficial considering the changing regulatory landscape that poses a threat to the use of 14 of the 16 UV filters currently employed in the US. The approval of BEMT would significantly broaden sun protection options for both formulators and consumers, ensuring the availability of safe and effective sunscreens.16
Sunscreen sustainability may be a tad difficult to tackle however, it is often said that opportunities exist where there are challenges. Therefore, the significant solutions that lie at the intersection of clean beauty and sun care remain to be seen.
Changing Consumer Preferences
Nowadays, considering the wealth of information readily available to the public, it is no wonder that consumers have become more knowledgeable about the environmental and human health impact of conventional cosmetics and are now pushing for more sustainable product formats that utilize safe, ethically sourced and eco-friendly ingredients. This has paved the way for the emergence of “clean beauty,” a term which is often used to refer to cosmetics and personal care products formulated with ingredients regarded as safe, non-toxic and environmentally sustainable. Although this term is non-regulated with varying definitions and guidelines across different brands and organizations, one thing is clear—there is a growing demand for products which align with clean beauty ethos. The clean beauty market alone is estimated to reach $22 billion by 2024;2 it is, therefore, not hard to see why brands such as RMS Beauty, Coco Kind, Tula, Native, Burt’s Bees3 and many others catering to this movement have been wildly successful and are redefining beauty and personal care standards around the world.As a result of this shift in consumer preferences, many product formats are being re-engineered to achieve better safety and sustainability profiles; sun care products are no exception. Sunscreens are mostly formulated as emulsions (creams and lotions) to be delivered as leave-on products and are typically designed by incorporating UV filters into a stable emulsion base. The process of re-formulation for sunscreens is not without its unique limitations as formulators must simultaneously grapple with the re-design of the sunscreen emulsion base to be both stable and sustainable using less traditional emulsifiers whose properties are not fully understood, while ensuring that the blend of UV filters incorporated into the formulation are compatible with the emulsion base and are deemed safe for use by the appropriate regulating body due to constantly changing regulatory guidelines. Thus, re-formulation, which is relatively less complex and better understood with products like cleansers and wash-off products, becomes more challenging in the case of sun care products.
Changing Regulatory Landscape
Many existing UV filters are increasingly being regulated or outrightly banned in formulations owing to environmental and human health safety concerns. Currently, a total of 45 organic UV filters are permitted to be added at maximum limits of 2 to 20% in cosmetics in the EU, US, China and Japan, with only 14 of these plus two inorganic filters (zinc oxide and titanium dioxide) allowed in the US (Table 1).1,4Table 1: US FDA Approved UV Filters4
Similarly, a new ordinance banning the use of all sunscreens containing organic UV filters and stipulating the use of only mineral sunscreens (containing inorganic filters) went into effect in Maui County of the state of Hawaii, as of October 2022.8 These are instances that establish the regulation and/or banning of UV filters as a global phenomenon alongside the looming possibility of more restrictions being placed on sunscreen filters without replacements, as evidenced by the fact that under the 2019 FDA Proposed Tentative Final Sunscreen Monograph, aminobenzoic acid (PABA) and trolamine salicylate have been deemed as not GRASE due to safety issues and will likely be dropped from the list of US approved UV filters in the near future while no single new UV filter has been approved for use in cosmetics since avobenzone in 1996 thus, constituting a ‘pain point’ in the formulation of eco-friendly sunscreens.9,10
Environmental Impact of UV Filters
Hard corals exposed to organic UV filters undergo rapid and complete coral bleaching, even when present in very low concentrations; hence, the global decline of coral reefs at an unprecedented rate may be attributed to UV filters used in sunscreens. The reference studies for these bans are significantly flawed in their experimental design since validated and standardized testing methods for corals are still at the developmental stage.11,12 Still, coral destruction is a major reason for bans on various organic UV filters in some coastal regions., An estimated annual 10,000 tons of UV filters are used globally, with reportedly 25% of applied sunscreen eventually making its way into water bodies thus, the occurrence of these filters in aqueous environments is inevitable, as indicated by the sheer number of studies highlighting the detection of UV filters in marine ecosystems.11,12Typically, organic UV filters are transferred to the environment through two major pathways- directly through wash-off from skin and clothing by humans during recreational activities, and indirectly through industrial discharges, wastewater effluents, runoffs, and domestic uses. It is pertinent to note that coastal tourism plays a major role in the direct transfer of these UV filters into the environment, as it has been reported that the increase in tourist population and concentration of these UV-blocking compounds in the water of these areas are correlated. While the photostability of UV filters is a desirable quality in sunscreen formulations, it is less desirable once released into aquatic environments, where they are likely to form toxic by-products, through direct or indirect photolysis.11,12 Chlorinated by-products formed via photolysis in chlorous environments; e.g., pool water, pose a serious threat to human health. Furthermore, most organic UV filters tend to bioaccumulate in biota due to their high lipophilicity and poor biodegradability, severely impacting the survival, development, and reproduction of these organisms.11
The widespread use of the inorganic filters—titanium dioxide and zinc oxide in ‘reef safe sunscreens’—is supported by a general belief that they are safer. Of the 16 currently approved active ingredients for sunscreen in the US, only these two are recognized as GRASE (generally regarded as safe and effective) lending credence to this belief. However, the use of a substance may only be termed “safe for the environment,” based on its intrinsic hazard profile and the results of an environmental risk assessment (ERA).11
Studies have shown that inorganic filters are equally as toxic to biota as their organic counterparts, especially in nanoparticle forms, leading to respiratory difficulties in fish and some other aquatic organisms. In one study, manufactured nano-sized titanium dioxide led to physiological damage on the trout species, Oncorhynchus mykiss. Titanium dioxide has also been proven to cause oxidative stress, increase of breathing frequency, bewildered swimming and changes in superoxide dismutase and catalase activity, while zinc oxide has been shown to cause tissue ulceration in larvae. It must be noted that a problem with mineral sunscreens containing a combination of these inorganic filters is the negative sensory feel they impart, which becomes more pronounced and unacceptable in demographics with darker skin tones. Not only do these filters present a challenge to the consumer, but they are also notably difficult to formulate with as well; hence, incorporating these filters in their nanoparticulate forms into sunscreens for ease of formulation and enhanced performance was developed to mitigate this issue.11 However, with concerns being raised about the harmful environmental impact of zinc oxide and titanium dioxide nanoparticles, there is a growing need for safer and more sustainable alternatives.11
Human Health Impact of UV Filters
The probable deleterious effects of UV filters on human health in the long term, particularly with respect to their endocrine-disrupting properties, are just as concerning. According to studies, people are exposed to organic UV filters through three pathways: dermal exposure, ingestion and inhalation. In a series of studies conducted by the US FDA on healthy volunteers, it was found that plasma concentrations of UV filters exceeded non-toxicological limits thus, confirming that sunscreen compounds are absorbed into the skin via topical application.1 Another possible means of dermal exposure are textiles and clothing.1 Benzophenone-3 has been reported in 70% of infant clothing and textiles in US while other benzophenone derivatives were found in pantyhose fabric collected from six countries. The oral ingestion of contaminated water can also lead to accumulation of UV filters in humans. Many studies have quantified the contamination of organic UV filters in drinking water or drinking water sources.1It is also possible for humans to be exposed to organic UV filters that have been washed off while swimming in pool water, via ingestion and dermal absorption.1 The phenomenon of biomagnification which occurs when contaminants that accumulate in low-trophic level species are later detected in their predators, is closely associated with bioaccumulation in marine organisms hence, seafood consumption is an avenue through which sunscreen agents are ingested by humans.11 The presence of UV filters in human breast milk, urine and plasma has been described in various studies and in one study, it was reported that more than 75% of analyzed human milk samples were contaminated with UV filters, indicating a possible exposure of breastfeeding infants to the sunscreen compounds.1 Indoor air is another source of human exposure to many semi-volatile organic chemicals, including organic UV filters. In a study, benzophenone-3 was found in 81 indoor air samples collected from New York. This compound has also been detected in other places within the US, such as in the greater Boston area and in California, as well as places outside the US e.g China.1
The Way Forward
The global sun care market is purported to expand at a compounded annual growth rate of 8.3% between 2023 and 2030 due to rising pollution, negative effects of sun exposure and increased awareness of personal care thus, researchers around the world continue to dedicate efforts towards sunscreens and sunscreen-related innovations, many of which are intended to address the challenges of sunscreen sustainability.13 The safety concerns surrounding several existing sunscreen actives have prompted a demand for the creation of new UV-absorbing compounds that can offer effective protection from the sun. As a result, many promising research studies and technological advancements are currently underway to develop innovative UV filters and sunscreen technologies.In 2022, a published patent by the University of Utah and the University of Princeton disclosed a composition utilizing oxidized amino acids obtained from protein sources as active ingredients in sunscreens.14 These amino acids exhibit excellent UV-protective absorption and energy dissipation properties, are naturally derived from compounds called kyurenines and can be easily broken down by living organisms, making them an ideal choice for replacing xenobiotic sunscreens, which are currently a cause for environmental concern.14
In response to the problem of skin whitening often presented by mineral screening agents, a patent was published in 2022 detailing a non-whitening composition incorporating an acrylic polymer and a dextrin ester which reportedly yield stable compositions with highly desirable qualities such as high SPF, no whitening effect and non-greasy feeling on skin.13 In May 2023 L’Oréal unveiled a new UV filtering technology, UVMune 400, designed to provide highly efficient shielding against ultra-long UVA radiation, which constitutes 30% of sun rays that previously went unfiltered.15 Another novel technology looking into the development of potentially non-irritating, sustainable and stable nanoemulsion sunscreen compositions is currently being worked on by researchers at the University of Miami.
On the regulatory front, DSM is making continuous efforts to obtain FDA approval for Bemotrizinol (BEMT), a highly photostable broad-spectrum filter that offers excellent UVA and UVB protection, even at low concentrations. Since 2016, DSM has been providing BEMT under the trade name of Parsol Shield as a UV light absorber for use in sunscreens and personal care cosmetic products. It is an easy-to-use ingredient that works well with both organic and inorganic UV filters. Despite being used globally since 1999, BEMT is not yet approved for use under the OTC Sunscreen Monograph. Obtaining its approval would be immensely beneficial considering the changing regulatory landscape that poses a threat to the use of 14 of the 16 UV filters currently employed in the US. The approval of BEMT would significantly broaden sun protection options for both formulators and consumers, ensuring the availability of safe and effective sunscreens.16
Sunscreen sustainability may be a tad difficult to tackle however, it is often said that opportunities exist where there are challenges. Therefore, the significant solutions that lie at the intersection of clean beauty and sun care remain to be seen.
- Huang, Y., Cheuk-Fung Law, J., Lam, T., and Sze-Yin Leung, K. Risks of organic UV filters: a review of environmental and human health concern studies. Science of The Total Environment (2021)
- Clean Beauty to Dominate the Beauty and Skincare Industry (2022) https://www.entrepreneur.com/en-in/news-and-trends/clean-beauty-to-dominate-the-beauty-and-skincare-industry/411314
- Green Cosmetics: The Push for Sustainable Beauty (2022) https://www.acme-hardesty.com/green-cosmetics-sustainable-beauty/
- Abou-Dahech, M., HS Boddu, S., Bachu, R.D et al. A mini-review on limitations associated with UV filters. Arabian Journal of Chemistry (2022)
- Thailand bans coral-damaging sunscreens in marine parks (2021) https://www.bbc.com/news/world-asia-58092472
- Another Sunscreen Paradise Enacts a Sunscreen Ban (2018) https://www.livescience.com/62598-bonaire-island-bans-sunscreen.html
- New Restrictions for the UV Filters Benzophenone-3 and Octocrylene (2022) https://www.coslaw.eu/new-restrictions-for-the-uv-filters/
- Mineral-Only Sunscreen Maui County (2022) https://www.mauicounty.gov/sunscreen
- Cloudy Outlook for Sunscreen Ingredients in the US (2022). https://cen.acs.org/business/consumer-products/Cloudy-outlook-sunscreen-ingredients-US/100/i42
- The PCPC Sunscreen Consortium: Defending UV filters under the FDA Sunscreen Monograph(2022).https://www.dsm.com/personal-care/en_US/sun-smart-community/shining-a-light-on-regulation/blog-1-uv-filters-under-fda-monograph.html
- Chatzigianni, M., Pavlou, P., Siamidi, A. et al. Environmental impacts due to the use of sunscreen products: a mini-review. Ecotoxicology (2022)
- Cadena-Aizaga, M.I., Montesdeoca-Esponda, S., Torres-Padrón, M.E et al. Organic UV filters in marine environments: An update of analytical methodologies, occurrence and distribution. Trends in Environmental Analytical Chemistry (2020)
- Sun Care Cosmetics Market Size, Share & Trends Analysis Report By Type (Conventional, Organic), By Distribution Channel (Specialty Stores, Online), By Product (SPF Foundation, SPF Sunscreen), And Segment Forecasts, 2023–2030 (2022) https://www.grandviewresearch.com/industry-analysis/sun-care-cosmetics-market-report
- Kynurenines, Layered SPF, Red Algae and More: Sunscreen Patent Roundup (2022). https://www.cosmeticsandtoiletries.com/research/literature-data/news/22618473/kynurenines-layered-spf-red-algae-and-more-sunscreen-patent-roundup
- Suncare Products Market- Growth, Trends and Forecasts (2023-2028) (2022) https://www.mordorintelligence.com/industry-reports/sun-care-products-market
- Can DSM’s Parsol Shield become first UV filter approved in over 20 years? (2022) https://www.dsm.com/personal-care/en_US/sun-smart-community/shining-a-light-on-regulation/blog-4-uv-filters-us-regulation-bemt.html
