SPF inflation in the sunscreen aisle

Something strange is happening in the sunscreen aisle. Shelves that had been stocked with bottles claiming an SPF, or a sun protection factor, of 30 now trumpet SPFs of 55, 70, even “110+.” This not-so-subtle escalation often comes with corollary pricing. Higher SPFs frequently cost more, but are they worth it?

Many dermatologists don’t think so.

“Once you get to SPF 50, it’s really getting silly,” said Boston dermatologist, James Spencer. “SPF refers to multiples of how much longer it takes the skin to burn,” but it isn’t a linear progression.

An SPF of 30 doesn’t offer twice as much protection as an SPF of 15, for example. An SPF 15 blocks 94% of UVB rays, SPF 30 blocks 97%, and SPF 45 blocks 98%.

Spencer recommends sunscreens with an SPF of 30, as does the American Academy of Dermatology, “because we know you’re not going to put enough on.”

In fact, the academy found that most sunscreen users put on only half as much sunscreen as they should to get the product’s claimed SPF protection. Making matters worse is the fact that sunscreen doesn’t last all day and needs to be reapplied every few hours.

The Food and Drug Administration began requiring SPF ratings on sunscreens sold in the U.S. in 1978. But SPF ratings only measure one type of sun protection. Sunlight consists of about 95% UVA, the ultraviolet light that contributes to skin cancer and wrinkles, and 5% UVB, which is responsible for sunburn. SPF only applies to UVB. It does not indicate UVA protection.

While many sunscreens claim to be broad spectrum — protecting the skin from both UVB and UVA — there’s no way of knowing how much UVA protection is included in a sunscreen. Yet. This October, the Food and Drug Administration “intends to publish rules to address sunscreen formulation, labeling and testing requirements for both ultraviolet B and ultraviolet A protection,” according to FDA spokeswoman Shelly Burgess.

susan.carpenter@latimes.com