Proposed FDA Limit on Sunscreen SPF a Bad Idea, Says Expert

Kate Johnson

March 17, 2012

March 17, 2012 (San Diego, California) — Five years from now, current sun protection factor (SPF) testing on sunscreen will be "a thing of the past," and will be replaced by the detection of biologic markers of ultraviolet (UV) damage, according to research reported here at the American Academy of Dermatology 70th Annual Meeting.

The prediction is ironic; new sunscreen labeling is expected to be approved by the US Food and Drug Administration this summer, after more than 30 years of debate.

The labeling will "make it a little easier...for us to explain to our patients how to choose a sunscreen," said Darrell Rigel, MD, clinical professor of dermatology at New York University Medical Center in New York City.

The new rules could limit sun protection claims on products with SPF above 50, which will be labeled as simply "SPF 50 plus," which is ill-advised, he said.

The basis for the proposed rule is scientific evidence suggesting only a marginal increase (about 1%) for sunscreens with an SPF above 50, compared with those with an SPF of 50, he said. In addition, higher prices are associated with higher SPF formulations.

However, the studies on SPF protection are based on clinical sunscreen application guidelines of 2 mg/cm², which are not realistic, he said.

"The reality is, nobody uses that [application]; you would be as white as a sheet of paper if you used that. People typically apply only 25% to 50% of the rated amount. Because of that, you're getting — in the real world — more forgiveness with the higher SPF."

According to a study by his group, currently in press, formulations that promise SPF protection of up to 50 rarely provide even an SPF protection of 15 in real-life settings.

At 50% of the recommended application level, only the SPF 70 and 100 sunscreens gave a level of protection of 30; at 25% of the recommended application level, they provide a level of protection of 15, he said.

"At the end of the day, there's a reason to have greater than SPF 50 in the real world because in the real world it makes a difference."

Additionally, a catch-all "SPF 50 plus" label could encompass anything from SPF 51 to 100, he said. "For some fair-skinned people, that difference matters."

With an SPF 50 labeling cap "what's the incentive for researchers and manufacturers to make a better sunscreen if they're not going to get credit for it?"

Although the new labeling should take most important factors into account, there are a few that have been left out, including sunscreen containers (one recent study showed that pumps are superior to bottles and roll-ons), photostability (there is nothing in the labeling to show how quickly it breaks down in sunlight), and cosmetic acceptability — "if it's really gooey or greasy, nobody will use it," he explained.

In the future, "there will be biologic markers to see what cells have changes when they're exposed to UV light with and without the sunscreen. Five years from now, SPF will be a thing of the past," he said.

Dr. Rigel reports doing efficacy testing and consulting for many sunscreen companies.

American Academy of Dermatology (AAD) 70th Annual Meeting: Presented March 16, 2012.


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