(Reuters Health) - While most high-SPF sunscreens in the U.S. meet national standards for ultraviolet A (UVA) protection, about half don’t meet European standards, a recent study found.
U.S. regulations recognize the importance of blocking a wide range of UV wavelengths to reduce skin cancer risk, but the standards may not be high enough to meet that goal, researchers say.
Currently, U.S. products only measure SPF based on protection against ultraviolet B rays, which cause sunburn. This number doesn’t say much about protection against ultraviolet A light, which is linked to aging, wrinkling and skin cancer.
Many sunscreens with sun protection factor (SPF) 50 or above and labeled “broad spectrum” - because they protect against both UVA and UVB rays - didn’t meet the higher standards created by the European Union, which may indicate a need for new UV filters in U.S. products, the study team writes in the Journal of the American Academy of Dermatology.
“I work with melanoma patients every day, and I’m a big believer in sunscreen use. When used correctly, daily use decreases skin cancer and prevents signs of early aging,” lead study author Steven Wang of Memorial Sloan Kettering Cancer Center in New York told Reuters Health.
In recent years, U.S. researchers have paid more attention to joint UVA and UVB protection, and the Food and Drug Administration issued a 2011 ruling that used “critical wavelength” to measure UVA protection. This method is more lenient than Europe’s UVA "protection factor" method.
Wang and colleagues studied 20 best-selling U.S. sunscreen products ranging from 15 to 100 SPF and marketed as broad-spectrum. They tested the products based on the critical wavelength requirement in the U.S. and the UVA protection factor test in Europe.
Nineteen of the 20 products met U.S. standards, and 11 met European standards. Of the nine products that failed EU standards, eight were SPF 50 or higher.
Part of the limitation for U.S. manufacturers is the lower number of effective long-range UVA filters available, Wang said. In addition, only 17 UV filters or active ingredients are approved for use in U.S. products.
“It’s important to revisit the issue of sunscreen innovation and add new filters into the formulation to improve protection,” Wang said. “We’re always looking for new ways to improve protection by adding inactive ingredients with a better film-forming technology.”
Several UV filters are under FDA review, including four that provide long-range UVA protection. The Sunscreen Innovation Act of 2014 was passed to expedite the review process for sunscreen additives, and eight proposed ingredients, including two common in European products, were denied in 2015 due to a lack of data to support safety. (bit.ly/2fZ0YK3)
In November 2016, the FDA issued new guidelines for chemical and human studies that manufacturers will need to conduct to win approval for new ingredients in over-the-counter sunscreens. In particular, companies must provide data from a “maximal usage trial” to determine whether an ingredient is absorbed into the blood.
“It’s hard for the U.S. to get that high UVA protection without new filters,” said Henry Lim of Henry Ford Hospital in Detroit. Lim, who wasn’t involved with the study, has previously researched UV radiation and photosensitivity.
“Essentially, sunscreens in Europe have a better probability of balanced protection, and the U.S. system is not as sensitive for UVA,” he told Reuters Health. “U.S. manufacturers are waiting for approval to create and market that better balance.”
SOURCE: bit.ly/2m3Jy2B Journal of the American Academy of Dermatology, online February 24, 2017.