Toxic Chemicals in Sunscreen
As summertime rolls around, the sun’s rays become stronger and many of us find ourselves spending more time outside. Sunscreen can be an important tool for protecting your skin from the sun, but selecting the best one for yourself can be intimidating. With a wide range of products available, it’s important to consider not only the effectiveness of the sunscreen in protecting against UV radiation, but also its impact on the health of your body and the environment.
Ingredients of Concern
Some ingredients of concern that commonly show up in sunscreen are:
Avobenzone – Avobenzone is a popular active ingredient in sunscreens for its ability to protect against the full spectrum of UVA rays. It has been linked to endocrine disruption [1] and aquatic toxicity [2][3] . According to a 2019 proposed FDA ruling on sunscreens, avobenzone was listed (along with 11 other chemicals, a number of which are also listed in this article) as not achieving GRASE (generally recognized as safe and effective) status due to inadequate data to support a safety finding [4].
Homosalate – A common sunscreen ingredient that absorbs UVB rays to prevent direct skin exposure. This ingredient has raised concerns regarding its potential hormone disrupting activity [5] and it may also enhance the absorption of pesticides when used concurrently with or near pesticide-containing products such as in some bug sprays or for people working in an agricultural setting [6][7].
Octinoxate – This UV filtering ingredient can be listed as octinoxate, octyl methoxycinnamate (OMC), or ethylhexyl methoxycinnamate on the label. Numerous animal studies have linked it to endocrine disruption and reproductive toxicity [8][9][10] . Due to its threat to coral reefs and contribution to water pollution, this chemical has been banned in sunscreens sold or distributed in Hawaii since 2021 [11].
Oxybenzone – Oxybenzone is a common sunscreen ingredient, though its use by manufacturers has declined in recent years. It may be listed on the label as oxybenzone or benzophenone-3. It has been associated with skin and eye irritation, significant toxicity to aquatic life, and potential endocrine disruption [12] . A number of studies have found that it is especially problematic for coral [13][14][15] and it was included in Hawaii’s 2021 ban along with octinoxate [16].
Understanding Sunscreen Labels
Reef Safe & Why Coral Reefs Are Important: Some sunscreens labeled as “reef safe” contain ingredients known to harm coral reefs. This is because there are no legal requirements or regulations for the use of the term “reef safe” on packaging. If the active sunscreen ingredient is anything besides non-nanomaterial titanium dioxide or non-nanomaterial zinc oxide, it is possible that the ingredient may hurt coral reefs. Coral reefs are important for the immense biodiversity they support, as well as for the livelihoods of fishermen and economies dependent on tourism. Coral reefs also protect coastlines [17] from storms and erosion, and they remove carbon dioxide [18] from the atmosphere.
Understanding UV Spectrum: Ultraviolet light, aka UV light, is light from the sun that is invisible to the naked eye. Sunscreen works to protect humans from two different kinds of UV light. UVA light has a longer wavelength and is the kind of ray associated with premature aging of the skin. UVB light has a shorter wavelength and is the ray associated with sunburn and damage to the skin. Protection against both is crucial.
Choosing the Right SPF: SPF stands for sun protection factor. The number indicates the level of protection against UVB rays, but the numbering system isn’t user-friendly. A higher SPF doesn’t mean the amount of coverage jumps up significantly. SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97% of UVB rays, SPF 50 blocks 98% of UVB rays, and SPF 100 blocks 99% of UVB rays. SPF is a measure of protection against UVB rays only. But remember that protection against UVA rays is important too, so choose a “broad spectrum” sunscreen, which protects against both UVA and UVB rays.
Tips for Choosing a Safer Sunscreen & Safe Sun Tips
- Shop certified sunscreens.
- Opt for titanium dioxide or zinc oxide as the active ingredient in your sunscreen. These are the only two active ingredients that have achieved GRASE status, according to the FDA [19].
- Titanium dioxide: A naturally-occurring mineral found in the earth’s crust. Titanium dioxide protects against UVB rays and some UVA rays, but may not provide full UVA protection. Titanium dioxide is safe for people and planet in non-nanoparticle forms. More research needs to be done to determine the safety of applications containing nanoparticle forms.
- Zinc oxide: Zinc oxide is a naturally-occurring UV absorber. Zinc oxide offers broad spectrum protection, as it protects against both UVA and UVB rays. Like titanium dioxide, it is safe in its non-nanoparticle form and more research is needed to understand safety when it comes to nanoparticle zinc oxide.
- Avoid spray sunscreens, particularly those containing propellants. Aside from the fact that many of them contain the harmful ingredients listed above, they also tend to contain other problematic ingredients such as alcohol, which can irritate and dry out the skin. The nature of the spray application also lends itself to missing areas of the skin, and poses additional concerns when the product is inhaled.
- Cover up and find shade. We suggest using clothing and hats as an additional layer of protection. Color, material, and weave all contribute to the level of protection fabrics provide. In general, the tighter the weave, the more protection from the sun. Avoid the strongest sun. If possible, skip the sun between 10 am and 2 pm.
- Don’t forget Vitamin D. The bulk of Vitamin D [20] is absorbed through the skin from the sun. So if you completely avoid the sun, you could be missing out on this crucial vitamin that the majority of Americans are deficient in. Go outside early in the morning or later in the afternoon to avoid the strongest sun. Consult your doctor to learn how to safely get vitamin D from the sun.
References
[1] Ahn, S., An, S., Lee, M., Lee, E., Pyo, J. J., Kim, J. H., Ki, M. W., Jin, S. H., Ha, J., & Noh, M. (2019, April 23). A long-wave UVA filter avobenzone induces obesogenic phenotypes in normal human epidermal keratinocytes and mesenchymal stem cells - archives of toxicology. SpringerLink. https://link.springer.com/article/10.1007/s00204-019-02462-1.
[2] Boyd, A., Stewart, C. B., Philibert, D. A., How, Z. T., El-Din, M. G., Tierney, K. B., & Blewett, T. A. (2021, January 1). A burning issue: The effect of Organic Ultraviolet filter exposure on the behaviour and physiology of Daphnia Magna. Science of The Total Environment. https://www.sciencedirect.com/science/article/abs/pii/S0048969720352360?via%3Dihub.
[3] Lee, S., Ka, Y., Lee, B., Lee, I., Seo, Y. E., Shin, H., Kho, Y., & Ji, K. (2023, December). Single and mixture toxicity evaluation of Avobenzone and homosalate to male zebrafish and H295R cells. Chemosphere. https://www.sciencedirect.com/science/article/abs/pii/S0045653523025419.
[4] Michele, T. (2022, December 16). An Update of Sunscreen Requirements: The Deemed Final Order and the Proposed Order. U.S. Food and Drug Administration. https://www.fda.gov/drugs/cder-conversations/update-sunscreen-requirements-deemed-final-order-and-proposed-order.
[5] Scientific Committee on Consumer Safety (SCCS). (2021, June 25). OPINION on Homosalate - public health. European Commission. https://health.ec.europa.eu/system/files/2022-08/sccs_o_244.pdf.
[6] Brand RM, Pike J, Wilson RM, Charron AR. Sunscreens containing physical UV blockers can increase transdermal absorption of pesticides. Toxicol Ind Health. 2003 Feb;19(1):9-16. doi: 10.1191/0748233703th169oa. PMID: 15462532.
[7] Macfarlane E, Carey R, Keegel T, El-Zaemay S, Fritschi L. Dermal exposure associated with occupational end use of pesticides and the role of protective measures. Saf Health Work. 2013 Sep;4(3):136-41. doi: 10.1016/j.shaw.2013.07.004. Epub 2013 Aug 9. PMID: 24106643; PMCID: PMC3791087.
[8] Schlumpf M, Schmid P, Durrer S, Conscience M, Maerkel K, Henseler M, Gruetter M, Herzog I, Reolon S, Ceccatelli R, Faass O, Stutz E, Jarry H, Wuttke W, Lichtensteiger W. Endocrine activity and developmental toxicity of cosmetic UV filters--an update. Toxicology. 2004 Dec 1;205(1-2):113-22. doi: 10.1016/j.tox.2004.06.043. PMID: 15458796.
[9] Axelstad, M., Boberg, J., Hougaard, K. S., Christiansen, S., Jacobsen, P. R., Mandrup, K. R., Nellemann, C., Lund, S. P., & Hass, U. (2010, November 6). Effects of pre- and postnatal exposure to the UV-filter octyl methoxycinnamate (OMC) on the reproductive, auditory and neurological development of rat offspring. Toxicology and Applied Pharmacology. https://www.sciencedirect.com/science/article/abs/pii/S0041008X10004242.
[10] Krause M, Klit A, Blomberg Jensen M, Søeborg T, Frederiksen H, Schlumpf M, Lichtensteiger W, Skakkebaek NE, Drzewiecki KT. Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters. Int J Androl. 2012 Jun;35(3):424-36. doi: 10.1111/j.1365-2605.2012.01280.x. PMID: 22612478.
[11] Hawai‘i State Legislature. (2018). Relating to Water Pollution SB2571 SD2 HD2 CD1. State of Hawaii. https://www.capitol.hawaii.gov/session/archives/measure_indiv_Archives.aspx?billtype=SB&billnumber=1052&year=2018.
[12] National Center for Biotechnology Information (2025). PubChem Compound Summary for CID 4632, Oxybenzone. Retrieved July 2, 2025 from https://pubchem.ncbi.nlm.nih.gov/compound/Oxybenzone.
[13] Downs, C.A., Kramarsky-Winter, E., Segal, R. et al. Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Arch Environ Contam Toxicol 70, 265–288 (2016). https://doi.org/10.1007/s00244-015-0227-7.
[14] Djordje Vuckovic et al.,Conversion of oxybenzone sunscreen to phototoxic glucoside conjugates by sea anemones and corals.Science376,644-648(2022).DOI: 10.1126/science.abn2600.
[15] Downs, C. A., Bishop, E., Diaz-Cruz, M. S., Haghshenas, S. A., Stien, D., Rodrigues, A. M. S., Woodley, C. M., Sunyer-Caldú, A., Doust, S. N., Espero, W., Ward, G., Farhangmehr, A., Samimi, S. M. T., Risk, M. J., Lebaron, P., & DiNardo, J. C. (2021, November 12). Oxybenzone contamination from sunscreen pollution and its ecological threat to Hanauma Bay, Oahu, Hawaii, U.S.A. Chemosphere. https://www.sciencedirect.com/science/article/abs/pii/S004565352103352X?via%3Dihub.
[16] Hawai‘i State Legislature. (2018). Relating to Water Pollution SB2571 SD2 HD2 CD1. State of Hawaii. https://www.capitol.hawaii.gov/session/archives/measure_indiv_Archives.aspx?billtype=SB&billnumber=1052&year=2018.
[17] NOAA. (2017) What is eutrophication? National Ocean Service website, https://oceanservice.noaa.gov/facts/eutrophication.html.
[18] National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 280 Carbon Dioxide. Retrieved July 6, 2023 from https://pubchem.ncbi.nlm.nih.gov/compound/Carbon-Dioxide.
[19] Michele, T. (2022, December 16). An Update of Sunscreen Requirements: The Deemed Final Order and the Proposed Order. U.S. Food and Drug Administration. https://www.fda.gov/drugs/cder-conversations/update-sunscreen-requirements-deemed-final-order-and-proposed-order.
[20] Nair, R., & Maseeh, A. (2012). Vitamin D: The "sunshine" vitamin. Journal of pharmacology & pharmacotherapeutics, 3(2), 118–126. https://doi.org/10.4103/0976-500X.95506.
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