Myth the higher the SPF, the longer you can stay in the sun
Fact: No, SPF isn’t an indication of how long a product protects you from the sun but how well it does so. What’s more, SPF doesn’t refer to the product’s ability to shield you from UVA rays, which have been linked to causing wrinkles. Your best bet: sunscreen labeled “broad-spectrum” (which means it covers both UVA and UVB rays) with an SPF of 30. Why? while an spf of 15 screens out only about 93 percent of UVB light, an SPF of 30 filters out 97 percent—and those any higher don’t offer much more benefit. Remember: any sunscreen will be effective only if it’s reapplied at least every three hours; use at least a coin size of it on your face and a shot-glass–size amount on your body.