SPF 15 or higher for UVB protection. The SPF factor rates how effective the sunscreen is in preventing sunburn caused by UVB rays. If you’d normally burn in 10 minutes, SPF 15 multiplies that by a factor of 15, meaning you could go 150 minutes before burning.
For the vast majority of people, SPF 15 is fine, Leffell tells WebMD. But people who have very fair skin, a family history of skin cancer, or conditions like lupus that increase sensitivity to sunlight should consider SPF 30 or higher.
Keep in mind that the higher the SPF, the smaller the increased benefit: contrary to what you might think, SPF 30 isn’t twice as strong as SPF 15. While SPF 15 filters out 93% of UVB, SPF 30 filters out 97%, only a slight improvement.
UVA protection. There is no rating to tell you how good a sunscreen is at blocking UVA rays, says Leffell. So when it comes to UVA protection, you need to pay attention to the ingredients.
Look for a sunscreen that contains at least one of the following, Leffell says: ecamsule, avobenzone, oxybenzone, titanium dioxide, sulisobenzone, or zinc oxide. Any of those should do the trick.
Ecamsule. One newly approved ingredient that blocks UVA is ecamsule. It’s been available in Europe and Canada, as Mexoryl SX, since 1993. In the U.S., ecamsule is now sold in L’Oreal’s Anthelios SX products. It isn’t cheap. A 3.4 ounce tube – barely enough for 4 full-body applications -