How much SPF do you really need?

When it comes to sun protection, bigger isn’t always better. You’re good with SPF 50, and though you’ll see products with SPF 70 (or even 100!) FDA says that these are “inherently misleading” because any additional protection is misleading. In fact, Australia, Canada and Japan have set a cap of SPF 50 on sun protection products sold within their borders.

Here are the numbers. SPF 50 already blocks 98% of the UV rays and SPF 100 blocks 99% — so you’re not getting double the protection. Experts also say it’s more important to apply the right amount. Even if you have SPF 50, but apply half the recommended dosage on the bottle, you can just be getting the functional equivalent of SPF 25 or less. Most people also forget to reapply sunscreen.

SPF also protects you just from UVB rays, but your sunscreen should also give UVA protection. UVA is not blocked by clouds or glass (so you can be exposed even when you’re indoors!) penetrate deep into the skin. UVA is what causes photoaging, or early wrinkles and pigmentation caused by sun exposure. Your SPF number does not indicate how much UVA protection you get.

So if you’re shopping for a sun protection product, look for SPF 50 and UVA protection, apply proper amounts and reapply every 2 hours, and double up with additional protection: hats, sunglasses, and if you’re exercising or swimming, UV-blocking sports fabrics.(We also have a special article on the best sun protection for runners.) Stay safe in the sun!