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  • Sunscreen by the Numbers

  • Sun screenSo, you've made the decision buy sunscreen-good for you! But that's when the real dilemma begins. Spray or lotion? Waterproof? And then, the big one: what SPF should you buy? SPF 7 doesn't seem enough…so your eyes wander to 15. That would work. Maybe you are fair skinned, so you consider 30. But then something else catches your eye. SPF 50, 75 and 100! Suddenly that bottle of 30 in your hand seems as ridiculous and irresponsible as wearing nothing at all. But is it?

    Retailers are upping their SPF offerings in hopes of grabbing customers' attention. But if triple-digit SPF seems to good to be true, that's because it is. SPF 100 blocks only 1 percent more UVB rays than SPF 50, and less than 5 percent more than SPF 30. And there's more to a sunscreen than UVB protection. Jennie Muglia, MD, a dermatologist at Rhode Island Hospital, reminds us, "The SPF of a sunscreen, no matter how high, is a rating of its protection against UVB rays but tells nothing of its ability to block harmful UVA rays, which also cause skin cancer. That is why it is necessary to choose a sunscreen that is labeled to also provide broad-spectrum coverage for UVA."

    The most important thing to remember when choosing a sunscreen is that you have to reapply. Even if a sunscreen is waterproof, even if it claims to offer all-day protection, it must be reapplied to reap the maximum benefit. An average of an ounce (or about a shot glass worth) should be used on each application. For maximum protection, sunscreen should be applied a half-hour before sun exposure.

    Don't feel the need to shun the sun if you aren't wearing SPF 100. A lower SPF, applied correctly, will do the trick. If you are still wondering which sunscreen is best for you, let two organizations be your guide. The Skin Cancer Foundation and the American Academy of Dermatology evaluates products for efficacy and safety. Look for their seals of approval on products from sunscreen to lip balm to beach umbrellas. Their websites can also help you chose the right sunscreen for your skin type and lifestyle, as well as other skin care tips.