When selecting a sunscreen product, be sure to read the label before you buy. Experts recommend products with a sun protection factor (SPF) of at least 15. The SPF number represents the level of protection against UVB rays provided by the sunscreen — a higher number means more protection.
It is important to remember that sunscreen does not give you total protection. When using an SPF 15 and applying it correctly, you get the equivalent of 1 minute of UVB rays for each 15 minutes you spend in the sun. So, 1 hour in the sun wearing SPF 15 sunscreen is the same as spending 4 minutes totally unprotected.
Sunscreens labeled with SPFs as high as 100 are now available. Higher numbers do mean more protection, but many people mistakenly think that the SPF scale is linear — for example, that a sunscreen with an SPF 45 rating would give 3 times as much protection as one with an SPF of 15. This is not true. SPF 15 sunscreens filter out about 93% of UVB rays, while SPF 30 sunscreens fitler out about 97%, SPF 50 sunscreens about 98%, and SPF 100 about 99%. The higher you go, the smaller the difference becomes. No sunscreen provides complete protection. Regardless of the SPF, sunscreen should be reapplied about every 2 hours.
The SPF number indicates protection against UVB rays only. Sunscreen products labeled “broad-spectrum” protect against UVA and UVB radiation, but at this time there is no standard system for measuring protection from UVA rays. Products with an SPF of 15 or higher that also contain avobenzone (Parsol 1789), ecamsule, zinc oxide, or titanium dioxide are likely to be effective against UVB and most UVA rays.
The Food and Drug Administration (FDA), which regulates sunscreens in the United States, has proposed a new set of rules for sunscreen labels. Part of this includes a rating system for UVA protection. Under the new system, sunscreens would be rated from 1 to 4 stars, with 1 star being a low level of UVA protection and 4 stars being the highest. It is not yet clear when this new rule might go into effect.
Check for an expiration date on the sunscreen container to be sure it is still effective. Most sunscreen products are no longer as effective after 2 to 3 years.
Some sunscreen products can irritate skin. Many products claim to be “hypoallergenic” or “dermatologist tested,” but the only way to know for sure whether a product will irritate your skin is to apply a small amount for 3 days. If your skin does not turn red or become tender and itchy, the product should be okay for you.
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