SUNSCREEN SHOULD INCLUDE UV-A PROTECTION.

When you select a sunscreen this summer, be sure that you are getting all the protection you need against ultraviolet radiation, cautions Alexa Boer, chief resident in dermatology at Stanford (Calif.) Hospital and Clinics. Look for a product containing ingredients that screen out the shorter ultraviolet (UV-B) rays of the sun--known to cause burning and cancer--as well as the longer ultraviolet (UV-A) rays, more recently found to be potentially harmful. Some new products are available that offer improved protection against UV-A, she points out.

UV-A rays sometimes have been called the "safe" solar rays, and tanning salons have advertised UV-A exposure as a way to tan without danger. "But that's deceptive," Boer says. "We've found in the last few years that UV-A rays penetrate the skin more deeply than UV-B, are more apt to cause long-term skin damage, including wrinkles, and can enhance the cancer-causing effects of the UV-B rays over time. Sometimes, it's hard to tell if your sunscreen protects adequately against both UV-A and UV-B. In general, you get the best UV-A protection from products with titanium dioxide or a newer compound, avobenzone. A label that says `UV protection' may mean only that you're getting UV-B protection. Look for labels that list both kinds."

The sun protection factor number required on the label of sunscreens refers to UV-B. Boer, like many dermatologists, recommends using SPF15 or higher. The number is a guide to how long users can remain in the sun without burning. For example, an SPF15 sunscreen allows users to expose themselves to the sun 15 times longer than would be safe without protection. Actual safe exposure times vary widely, depending on intensity of the sun and sensitivity of the skin. Persons with dark skin often don't burn as easily, but they, too, should use sunscreen to protect against cancer and premature skin aging, Boer suggests.