To figure out how much protection a sunscreen provides, most consumers turn to a simple number: the SPF, or sun protection factor, listed on the label. Studies show that most consumers understand that the higher the number, the more the product protects the skin.

Unfortunately, studies also show that people often have the mistaken notion that the higher the SPF number of the sunscreen they use, the longer they can stay--and will stay--in the sun. In August 1999, the Journal of the National Cancer Institute published a study showing that use of higher-SPF sunscreens led to increased sun exposure. Two groups of French and Swiss volunteers used unlabeled sunscreen during their vacations. One group used SPF 10 and the other group used SPF 30. The group using the higher-SPF sunscreen spent 20 percent more time in the sun (72.6 hours vs. 58.2 hours) than the group using the lower-SPF sunscreen.

"Because of variations between individuals, products, exposures, and conditions of use, there is no really easy way to explain SPF in a few words," says FDA's Lipnicki. "In the past, it was explained in terms of the amount of time you could stay in the sun longer with sunscreen than without it before getting 'burned'. We have gotten away from that. Sunscreen should not be used to prolong time spent in the sun. Even with a sunscreen, you are not going to prevent all the possible damage from the sun. Some of the newer research in the last several years shows that the sub-erythemal doses [exposure to the sun that does not cause reddening of the skin], as little as one-tenth the energy needed to get a sunburn, start the process of skin damage of one sort or another."

In the final monograph completed last year, FDA proposed limiting SPF values on a sunscreen label to 30. Products with higher SPFs would be labeled "30+" (or "30 plus"). The agency took this action for two reasons: inadequacies in the testing methodologies for higher-level SPF formulations, and concern that the high SPF labeling may lead consumers to spend more time in the sun than they should.

The SPF portion of FDA's monograph immediately produced opposition from both industry groups and consumer organizations. The National Coalition for Sun Safety, an organization supported by the American Academy of Dermatology, advocated "a floor rather than a cap on SPF," wrote coalition co-chairmen Rex Arnonette, M.D., and Roger Ceilley, M.D. The organization wants a minimum level of SPF to ensure that all products provide some protection.

Industry, primarily represented by the Cosmetic, Toiletry and Fragrance Association (CTFA), opposed the 30-plus cap for several reasons, including consumer confusion, fear that manufacturers would remove effective sunscreen protection in their products to avoid misbranding, and unresolved scientific issues about UVA. With the deferral of the monograph's implementation, the industry, along with the agency, will have additional time to resolve the issues.
La Roche Posay Anthelios 40 Sunscreen

by Larry Thompson
Larry Thompson is the editor of FDA Consumer.