sunscreen master class; Are you wearing SPF but still getting burned.(sun protection factor)

Byline: Catherine Piercy

Here's an inconvenient truth: Most people purport to wear sunscreen-every day under makeup, certainly on ski slopes and at the beach-yet skin cancer rates are rising instead of falling, as is the number of women turning up at the dermatologist's office for sun-damage-reversing Fraxel and GentleWaves sessions. Of the 1 million new cases of skin cancer the Skin Cancer Foundation anticipates this year, more than 59,000 will be diagnosed as melanoma-the third most common form of cancer in women between the ages of 20 and 39. These findings are especially ironic since there are now more sunscreen choices than ever, with something for virtually every skin type and personality: There are weightless cooling formulas from Neutrogena, fuss-free sprays from Coppertone, speed-drying gels from PreSun, pocket-size wipes from Estee Lauder, and elegant, non-stinging eye creams from Shiseido and Clarins. So what are we doing wrong? And how can we guarantee future sunscreen success?

LEARNING THE LINGO

All sun care is not created equal. The most important piece of information on a sunscreen label is the indication of "broad spectrum" coverage-protection against both UVB rays (which burn) and UVA rays (which penetrate deeper into the skin to cause DNA damage and photo-aging). SPF ratings can be deceptive, as they indicate only the level of UVB coverage. (Dermatologists are currently petitioning the FDA to list a sunscreen's PPD/PFA-the numbers used to measure UVA protection.)

A working knowledge of active ingredients is also key: Physical blockers like titanium dioxide and zinc oxide work by reflecting UVA and UVB rays before they reach the skin. Chemical filters, on the other hand, absorb UVA radiation, converting it safely to heat, and are regularly blended with effective UVB filters like homosalate. The most powerful UVA absorbers are Mexoryl (which caused a frenzy when the FDA approved it last year, generating the kind of waiting lists more common to the latest hot-off-the-runway handbag), now available in La Roche-Posay's Anthelios SX and Lancome's UV Expert, and its formidable competitor Helioplex, the avobenzone-powered blend in Neutrogena's revamped sun-care collection. (Aveeno's sun products contain a similar formulation.)

safety in nUMBERS?

SPF ratings are soaring-Shiseido now offers a 55, Skin Effects by Dr. Jeffrey Dover a 60, Neutrogena a 70-but does a 50 or above provide that much more protection than a fifteen or a 30? "An SPF 30 offers significantly more protection than SPF 15, but the numbers game is misleading," says New York dermatologist Dennis Gross, M.D., who notes that above 30, a sunscreen's additional UV-absorbing abilities are negligible. In fact, higher SPF numbers signify little more than a formula's staying power. "An SPF 70 is generally heavier in texture, which makes it less likely to rub off quickly-but it's not giving you twice as much UV protection as an SPF 35," he says. In the end, sun-blocking success is less about the number on the bottle and more about the method by which you apply it, and how frequently.