Most dermatologists would agree: In a perfect world, everyone would wear sunscreen daily—clear skies or cloudy—whether you’re headed to work or a week in the West Indies. Slathering it on is, after all, your best protection against skin cancer and premature aging—aside from not going out in the sun at all (and, really, how realistic is that?). The thing is, whether you’re a 365-day-a-year addict or just a part-timer (most likely to apply only at the beach), sunscreen won’t do you any good unless you choose it and use it correctly.
Read the fine print. Not all sunscreens are created equal. So before you buy, check the bottle for one of three ingredients: Parsol 1789 (also called avobenzone), titanium dioxide, or zinc oxide. Although they work differently—Parsol 1789 is a chemical blocker that absorbs ultraviolet (UV) light and the other two are physical blockers that reflect it—the end result is the same: broad- or full-spectrum protection (the label will undoubtedly tout this attribute). Broad-spectrum sunscreens block both UVA rays, which are linked to a higher incidence of melanoma and cause premature aging (wrinkles, brown spots, freckles), and UVB rays, which cause sunburn.Prices vary widely for this sort of protection but the best way to choose is to find something that feels good on your skin. The better it feels, the more likely you’ll use it every day.
Be SPF- savvy. Sun Protection Factor indicates the amount of anti-UVB power in a product (currently, there is no standardized method of measuring UVA absorption). The higher the SPF, the longer you can stay out in the sun without burning—but the same level of SPF works differently on different skin tones. Dark skin, for instance, is less susceptible to sunburn because it contains more melanin (the body’s natural sunblock). Regardless, the American Academy of Dermatology recommends an SPF of at least 15. Less than that, and the level of protection plummets dramatically; higher than that, and the difference in protection is smaller, though 30 is still slightly better than 15, 45 is better than 30, and so on. Also, SPF is not cumulative: Layering SPF 30 on top of SPF 15 does not give you 45.
Apply liberally and often. It’s impossible to overuse sunscreen. In fact, one ounce (the equivalent of a full shot glass) is generally needed to cover all exposed areas of the body. If, however, you’re outside all day, once is never enough. Reapply every two hours or after swimming or heavy perspiring. And don’t let sunscreens labeled as “waterproof” give you a false sense of security. Although they may have a bit more staying power due to a stickier consistency, they will eventually rub or wash off, especially if you’re really active. Bottom line: Reapply, reapply, reapply.