The research found that the absorption of sunscreen ingredients goes beyond FDA guideline limits, yet the agency still advises using sunscreen for skin protection.
Exposing your skin to too much sun can pose deadly consequences. The Centers for Disease Control and Prevention points out that skin cancer is the most common type of cancer in the United States, and ultraviolet rays from the sun are its main cause, notes the Cleveland Clinic.
While the U.S. Food and Drug Administration (FDA) advises the public to use sunscreens for protection, the effects of these products may be more than skin deep.
“In this study, all four active ingredients tested were absorbed from each formulation tested, showing that absorption of sunscreens is not just a theory,” says one of the study’s authors, David Strauss, MD, PhD, the director of the division of applied regulatory science with the FDA’s Center for Drug Evaluation and Research.
“The fact that an ingredient is synced through the skin and into the body does not suggest the ingredient is unsafe,” he adds. “Rather, this finding calls for further testing to determine the safety of that ingredient for repeated use.”
Body Absorbs Sunscreen Chemicals
In this preliminary investigation, 24 healthy volunteers applied one of four common sun-protective products (either one of two sprays, a lotion, or cream) to three-quarters of their body surface four times a day for four days. Participants were split equally among men and women, were 58 percent African-American, and were an average age of 35 and a half.
Experts collected 30 blood samples from these individuals over the course of seven days and measured concentrations of avobenzone, oxybenzone, octocrylene, and ecamsule — common active ingredients in sunscreens.
After 1st day, all four products produced blood concentrations greater than 0.5 nanograms per milliliter (ng/ml), going beyond the threshold established by the FDA. The concentrations continued to increase over four days, suggesting that the ingredients were accumulating in the system. Rash was the most common side effect observed.
Do the Health Benefits of Using Sunscreen Outweigh the Risks?
In an editorial response to the study, Robert Califf, MD, with the Duke University School of Medicine, and Kanade Shinkai, MD, a dermatologist with the University of California in San Francisco, point out that previous research has raised concerns about the safety and effects of chemical sunscreens on endocrine (relating to hormone glands), reproductive, developmental, and cancer-related outcomes.
These doctors request for more deeper study to determine if the sunscreen benefit of preventing melanoma and other skin cancers outweighs other health risks.
“An urgent question involves absorption in infants and children, who have different ratios of body surface area to overall size and whose skin may absorb substances at differential rates,” they write. According to an article published in the Archives of Pediatrics and Adolescent Medicine, early exposure to chemicals may disrupt reproductive and neurological development, for example.
Are There Safe Sunscreen Ingredients Dermatologists Recommend?
As investigations continues, Dr. Califf and Dr. Shinkai suggest that physicians may recommend using sunscreen formulations containing ingredients such as titanium dioxide and zinc oxide, which the FDA calls generally recognized as safe and effective (GRASE).
“I think the average patient is going to be scared now and think, ‘Oh my God, what am I going to use?’” says Michele Green, MD, a dermatologist with Lenox Hill Hospital in New York City. “If patients are panic-stricken, they can always feel safe in using zinc oxide or titanium dioxide.”
The American Dermatology Association (AAD) stresses that you shouldn’t stop using sunscreen because of these results, noting that “these sunscreen ingredients have been used for several decades without any reported internal side effects in humans.”
As the industry and other interested parties develop further data, Dr. Strauss advises the public to continue to use sunscreens with other sun-protective measures.
“Broad-spectrum sunscreens with SPF values of at least 15 remain a critical element of a skin-cancer prevention strategy that includes other sun protective behaviors such as wearing protective clothing that adequately covers the arms, torso, and legs; wearing sunglasses and a hat that shades the whole head; and seeking shade whenever possible during periods of peak sunlight,” he says. For its part, the AAD recommends broad-spectrum and waterproof sunscreen with at least SPF 30.
As May is Skin Cancer Awareness Month, the Skin Cancer Foundation advises the public to learn more about shielding skin from sun damage and knowing the signs of skin cancer to increase the likelihood of an early diagnosis.
More Research on Sunscreen Ingredients Is Needed
The paper cites several study limitations, including that it was conducted in indoor conditions without exposure to heat, sunlight, and humidity, which may have affected the rate of active ingredient absorption. Also, because participants used multiple applications of sunscreen products, following the labeled dosage regimen, researchers weren’t able to determine the effects after a single application.
Spaulding Clinical Research, which partnered with the FDA on the clinical trials, reports that a second phase of the research tested six different sunscreen brands on 72 subjects, who applied sunscreen just under 1,000 times. While the firm does not foresee publishing additional results, the outcomes confirmed that the absorption of chemicals into the bloodstream is happening at a rapid rate.
“The lesson for now is that this is something to look out for, and that while we await the results of further testing, you should stick to dermatological recommendations for protecting your skin from the harmful effects of sun exposure,” says Cassandra Erato, MSN, the COO at Spaulding Clinical Research in West Bend, Wisconsin.