Sunscreens Made Simple

Neera R. Nathan, MD, MSHS Instructor of Dermatology Harvard Medical School Clinical Investigator, Manstein Lab Cutaneous Biology Research Center Massachusetts General Hospital Disclosures

Neither I nor my spouse/partner has a relevant financial relationship with a commercial interest to disclose. Objective

• To help healthcare professionals of all backgrounds address some of the most common sunscreen questions encountered in clinical practice Common Sunscreen Questions

• What does “broad spectrum” mean? • What’s the difference between “chemical” and “physical” sunscreen? • Is sunscreen safe for me? • Is sunscreen safe for the environment? • Is higher SPF better? • Is the sunscreen in my make-up enough? Decode the Sunscreen Label What Does “Broad-Spectrum” Mean?

• “Broad-spectrum” sunscreen – Protects against harmful ultraviolet rays, including: • UVA (protection against skin aging1) • UVB (protects against sunburns) – What does it NOT protect against? • Visible light (exacerbate dark spots!)

1 Yaar, M., & Gilchrest, B. (2007). Photoageing: Mechanism, prevention and therapy. British Journal of Dermatology, 157(5), 874-887. doi:10.1111/j.1365-2133.2007.08108.x What Is Visible Light?

• Comes from both natural (sunlight) and artificial sources (device screens) • Exacerbate post- inflammatory hyperpigmentation or melasma1 – Especially true for people with dark skin tones

1 Impact of long wavelength UVA and visible light on melanocompetent skin. (2008). Journal of Investigative Dermatology, 58(2). doi:10.1016/j.jaad.2007.10.513 How Do You Block Visible Light?

• Tinted sunscreen – Look for pigmentary titanium dioxide or iron oxide on the label – Range of shades and various formulations • Photoprotective clothing Decode Sunscreen Label What’s the Difference Between “Chemical” and “Physical” Sunscreen?

• May be misnomers1 and the term “chemical” has a negative connation • Organic (“chemical”) UV filters – i.e. ensulizole, octisalate, homosalate, octocrylene, octinoxate, oxybenzone, avobenzone – Broad-spectrum (UVA & UVB) • Usually combination of organic filters used to achieve this – Generally rub on clear • Includes spray-on formulations

• Inorganic (“physical”) UV filters – I.e. titanium dioxide and zinc oxide – Reflect & absorb UV – Broad-spectrum (UVA & UVB) • When large particles, have some protection against visible light – Can be very chalky • Usually nanosized

• There is not currently evidence to suggest that use of sunscreens containing organic filters legally sold in the United States are unsafe – Results of two JAMA studies1,2 suggest that certain sunscreens containing organic (“chemical”) UV filters are systemically absorbed • Unclear significance, if any, for human health – In vitro and animal studies have shown that high levels of oxybenzone may cause endocrine disruption3 – The FDA and the AAD still recommend sunscreen use along with other photoprotection while further research is being conducted – Oxybenzone is a known contact allergen in humans

1 Matta, M. K., Zusterzeel, R., Pilli, N. R., Patel, V., Volpe, D. A., Florian, J., . . . Strauss, D. G. (2019). Effect of sunscreen application under maximal use conditions on plasma concentration of sunscreen active ingredients. JAMA, 321(21), 2082. doi:10.1001/jama.2019.5586 2Matta, M. K., Florian, J., Zusterzeel, R., Pilli, N. R., Patel, V., Volpe, D. A., . . . Strauss, D. G. (2020). Effect of sunscreen application on plasma concentration of sunscreen active ingredients. JAMA, 323(3), 256. doi:10.1001/jama.2019.20747 3 S. Kim, K. ChoiOccurrences, toxicities, and ecological risks of benzophenone-3, a common component of organic sunscreen products: a mini- review Environ Int, 70 (2014), pp. 143-157 Are Sunscreens Safe?

• Inorganic (“physical”) UV blockers are generally recognized as safe and effective (GRASE) per FDA – Titanium dioxide and zinc oxide do not get absorbed into the bloodstream – Best for sensitive skin • Little guidance on photoprotection from visible light, including tinted sunscreens

1https://www.fda.gov/news-events/fda-voices/shedding-more-light-sunscreen-absorption What About Coral Reefs?

https://www.thenationalnews.com/uae/environment/hope-for-coral-reefs-after-scientists-find-resilient-species-1.885462 Are Sunscreens Safe for the Environment? – Beginning January 2021, Hawaii has banned OTC sales of sunscreens containing two organic filters due to concern over coral bleaching1 • Oxybenzone and octinoxate • In vitro evidence that organic filters are toxic to coral larvae, but at doses much higher than what is present in the environment2 – Organic UV filters has been found in different types of fish3 • Concern over bioaccumulation – Organic UV filters also found in water sources and is difficult to remove in treatment plants3

1Geisler, A. N., Austin, E., Nguyen, J., Hamzavi, I., Jagdeo, J., & Lim, H. W. (2021). Visible light Part Ii. photoprotection against visible and ultraviolet light. Journal of the American Academy of Dermatology. doi:10.1016/j.jaad.2020.11.074 2Downs 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 2016; 70: pp. 265-288. 3Schneider, S. L., & Lim, H. W. (2019). Review of environmental effects of oxybenzone and other sunscreen active ingredients. Journal of the American Academy of Dermatology, 80(1), 266-271. doi:10.1016/j.jaad.2018.06.033 Recommendations for People Concerns About Sunscreen Safety 1. Wear photoprotective clothing, including sunglasses and hats, and cover as much exposed skin as possible – Look for clothing with an ultraviolet protection factor (UPF) of 50+ • Measures protection through clothing • Blocks UV and visible light 2. Apply SPF30+ sunscreens with inorganic (“physical”) filters to remaining exposed skin Sun Protective Clothing

Slide adapted from Dr. A. Shadi Kourosh Decode Sunscreen Label Is Higher SPF Better?

• The American Academy of Dermatology (AAD) recommends broad-spectrum SPF 30+ sunscreen to exposed skin everyday1 – When worn as directed, someone who burns in 10 minutes could stay outside 30x longer (5 hours) without burning while wearing SPF30 sunscreen – Blocks 97% of UVB (causes sunburn)

1https://www.aad.org/public/everyday-care/sun-protection/sunscreen- patients/sunscreen-faqs Is Higher SPF Better?

• To achieve the SPF on the label, sunscreen needs to be applied at a dose of 2mg/cm2 – “teaspoon” rule suggests use of 1 teaspoon to head/neck, 2 teaspoons to the torso, 2 teaspoons to each extremity1 • Functionally, most individuals UNDER-APPLY sunscreen – As such, effective SPF used is usually less than the SPF on the label – Even though differences in protection between SPF30 and SPF100 are small (97% v 99%), over time, cumulative increase in UV damage may add up

1Stenberg, C. (1985). Sunscreen application and its importance for the sun protection factor. Archives of Dermatology, 121(11), 1400-1402. doi:10.1001/archderm.121.11.1400 2Geisler, A. N., Austin, E., Nguyen, J., Hamzavi, I., Jagdeo, J., & Lim, H. W. (2021). Visible light Part Ii. photoprotection against visible and ultraviolet light. Journal of the American Academy of Dermatology. doi:10.1016/j.jaad.2020.11.074 Is The Sunscreen in My Make-Up Enough?

• Cosmetic formulations contain pigments that provide modest UV and visible light protection through oxidation that affects skin color1 • Many foundations are formulated with SPF • Tinted Moisturizers • BB/CC Creams: “Beauty Balm” - All-in- one moisturizer, foundation and sunscreen (inorganic filter), some with anti-oxidants +/- “Color Corrector” Remember the “teaspoon” rule • Most users do not apply enough product amount to achieve coverage listed on label • “teaspoon” rule • Layering with broad-spectrum or tinted sunscreen may be best option Slide adapted from Dr. A. Shadi Kourosh

Please email me with any questions: [email protected]

Dr. A. Shadi Kourosh

Dr. Dieter Manstein