Products sold in Europe, Japan and South Korea offer more protection from the sun. In the U.S., the key ingredients aren't FDA-approved.

When dermatologist Dr. Adewole “Ade” Adamson sees people spritzing sunscreen as if it’s cologne at the pool where he lives in Austin, Texas, he wants to intervene. “My wife says I shouldn’t,” he said, “even though most people rarely use enough sunscreen.”

At issue is not just whether people are using enough sunscreen, but what ingredients are in it.

The Food and Drug Administration’s ability to approve the chemical filters in sunscreens that are sold in countries such as Japan, South Korea, and France is hamstrung by a 1938 U.S. law that requires sunscreens to be tested on animals and classified as drugs, rather than as cosmetics as they are in much of the world. So Americans are not likely to get those better sunscreens — which block the ultraviolet rays that can cause skin cancer and lead to wrinkles — in time for this summer, or even the next.

Sunscreen makers say that requirement is unfair because companies including BASF Corp. and L’Oréal, which make the newer sunscreen chemicals, submitted safety data on sunscreen chemicals to the European Union authorities some 20 years ago.