Many myths persist about sunscreen use and safety, and further sunscreen regulations may be impacted by legislation in the wake of the ongoing COVID-19 pandemic, according to Steven Q. Wang, MD, director of dermatologic surgery and dermatology, Memorial Sloan-Kettering Cancer Center, Basking Ridge, N.J.

A woman has sunscreen applied to her back. Aja Koska/Getty Images

Although sunscreens are regulated as an OTC drug under the Food and Drug Administration, concerns persist about the safety of sunscreen active ingredients, including avobenzone, oxybenzone, and octocrylene, Dr. Wang said in a virtual presentation at MedscapeLive’s annual Las Vegas Dermatology Seminar.

In 2019, the FDA proposed a rule that requested additional information on sunscreen ingredients. In response, researchers examined six active ingredients used in sunscreen products. The preliminary results were published in JAMA Dermatology in 2019, with a follow-up study published in 2020 . The studies examined the effect of sunscreen application on plasma concentration as a sign of absorption of sunscreen active ingredients.

High absorption

Overall, the maximum level of blood concentration went above the 0.5 ng/mL threshold for waiving nonclinical toxicology studies for all six ingredients. However, the studies had several key limitations, Dr. Wang pointed out. “The maximum usage condition applied in these studies was unrealistic,” he said. “Most people when they use a sunscreen don’t reapply and don’t use enough,” he said.

Also, just because an ingredient is absorbed into the bloodstream does not mean it is toxic or harmful to humans, he said. Sunscreens have been used for 5 or 6 decades with almost zero reports of systemic toxicity, he observed.

The conclusions from the studies were that the FDA wanted additional research, but “they do not indicate that individuals should refrain from using sunscreen as a way to protect themselves from skin cancer,” Dr. Wang emphasized.

Congress passed the CARES Act in March 2020 to provide financial relief for individuals affected by the novel coronavirus, COVID-19. “Within that act, there is a provision to reform modernized U.S. regulatory framework on OTC drug reviews,” which will add confusion to the development of a comprehensive monograph about sunscreen because the regulatory process will change, he said.

In the meantime, confusion will likely increase among patients, who may, among other strategies, attempt to make their own sunscreen products at home, as evidenced by videos of individuals making their own products that have had thousands of views, said Dr. Wang. However, these products have no UV protection, he said.

For current sunscreen products, manufacturers are likely to focus on titanium dioxide and zinc oxide products, which fall into the GRASE I category for active ingredients recognized as safe and effective. More research is needed on homosalate, avobenzone, octisalate, and octocrylene, which are currently in the GRASE III category, meaning the data are insufficient to make statements about safety, he said.

Vitamin D concerns

Another sunscreen concern is that use will block healthy vitamin D production, Dr. Wang said. Vitamin D enters the body in two ways, either through food or through the skin, and the latter requires UVB exposure, he explained. “If you started using a sunscreen with SPF 15 that blocks 93% of UVB, you can essentially shut down vitamin D production in the skin,” but that is in the laboratory setting, he said. What happens in reality is different, as people use much less than in a lab setting, and many people put on a small amount of sunscreen and then spend more time in the sun, thereby increasing exposure, Dr. Wang noted.

For example, a study published in 1988 showed that long-term sunscreen users had levels of vitamin D that were less than 50% of those seen in non–sunscreen users. However, another study published in 1995 showed that serum vitamin D levels were not significantly different between users of an SPF 17 sunscreen and a placebo over a 7-month period.

Is a higher SPF better?

Many patients believe that the difference between a sunscreen with an SPF of 30 and 60 is negligible. “People generally say that SPF 30 blocks 96.7% of UVB and SPF 60 blocks 98.3%, but that’s the wrong way of looking at it,” said Dr. Wang. Instead, consider “how much of the UV ray is able to pass through the sunscreen and reach your skin and do damage,” he said. If a product with SPF 30 allows a transmission of 3.3% and a product with SPF 60 allows a transmission of 1.7%, “the SPF 60 product has 194% better protection in preventing the UV reaching the skin,” he said.

Over a lifetime, individuals will build up more UV damage with consistent use of SPF 30, compared with SPF 60 products, so this myth is important to dispel, Dr. Wang emphasized. “It is the transmission we should focus on, not the blockage,” he said.

Also, consider that the inactive ingredients matter in sunscreens, such as water resistance and film-forming technology that helps promote full coverage, Dr. Wang said, but don’t discount features such as texture, aesthetics, smell, and color, all of which impact compliance.

“Sunscreen is very personal, and people do not want to use a product just because of the SPF value, they want to use a product based on how it makes them feel,” he said.

At the end of the day, “the best sunscreen is the one a patient will use regularly and actually enjoy using,” Dr. Wang concluded.

Dr. Wang had no relevant financial conflicts to disclose.

MedscapeLive and this news organization are owned by the same parent company.