Sunscreen protects, but only if it’s used correctly
Boer ture.
Deng
writes
for
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Sunblock is one of summer’s totems, along with pink-jacketed paperbacks and bottles of lime-favored beer. But for all its ubiquity, the elixir is often misused. Here are five myths, dispelled to help you protect yourself better.
1. You need sunscreen only on sunny days.
Plenty of people have had the unpleasant experience of going out on a cool, overcast day only to return with a nasty sunburn. Yet one of the most-cited reasons for forgoing sunscreen is cloud cover. Although clouds block some UV radiation, 80 percent still reaches the Earth’s surface.
2. The SPF is what matters.
Advice about sunscreen invariably begins with the recommendation to use something with an SPF value of 15 or greater, giving the impression that those three familiar letters are all you need to decide which sunscreen to buy. But SPF (“sun protection factor”) is an approximation of how much time you can spend in the sun without burning. An SPF 15 sunscreen, for example, will allow you to stay exposed 15 times longer without burning than if your skin was unprotected, while an SPF 30 product is said to extend this 30 times. Protectiveness against UV rays does not scale in proportion to the SPF value, however: SPF 15 lotions block 93 percent of UV rays; SPF 30, about 97 percent.
Sometimes, an inflated SPF value offers misleading assurance with little meaning). In fact, the false safety implied by ever-higher SPF numbers inspired regulators in Europe, Japan and Australia to cap SPF values. Sunscreens sold in those markets do not exceed 50.
3. Fair-skinned people have a greater need for sunscreen.
It’s true that some of us are more susceptible to sunburn than others. In part, this is related to the presence of melanin, a pigment in skin that absorbs wave- lengths of UV radiation. But that natural shield is not so strong that sunscreen can be jettisoned.
The mistaken notion that dark skin is naturally more protected propagates in insidious ways. For example, a 2006 study found that sunblock ads are much more prevalent in magazines with predominantly white readerships, compared with those aimed at black audiences. A lack of awareness of skin cancer risks among African-Americans is thought to contribute to black patients not seeking treatment immediately for suspicious skin lesions.
4. That old bottle is just fine.
Like spoiled milk, expired sunscreen is not much good. But consumers seem befuddled as to whether an expiration date represents a meaningful warning or merely a manufacturer being cautious. And according to one study, one-third of people don’t check the dates at all. Sunscreens expire because their ingredients deteriorate over time, losing their power.
Besides, if you’re applying sunblock properly, you probably won’t have any left over at the end of the summer, anyway. 5. Sunscreen is toxic. “Your sunscreen might be poisoning you,” declares a headline on the website for “The Dr. Oz Show.” “Is sunscreen dangerous?” asks U.S. News & World Report. Driving these worries are past studies linking particular sunscreen ingredients with undesirable byproducts and possible negative health effects. Some fear that it causes cancer, though the medical consensus says such concerns are overblown. The link between photodamage and skin cancer is well established; the possible adverse effects of sunscreen chemicals far less so. And sunblock products in the United States are rather well-regulated: The FDA has considered sunscreen an over-the-counter drug since the late 1970s, making it subject to more regulatory scrutiny than cosmetic lotions, fragrances or creams that also penetrate the skin.