By now we all know that the sun can kill: About 1 million new skin cancers are diagnosed each year in the United States, and about half of all new cancers are skin cancers, according to the American Academy of Dermatology. And thanks to increased awareness about skin cancer, we also know the summer mantra: Wear sunscreen, wear sunscreen, wear sunscreen. What we may not know, however, is how to choose and use sunscreen properly, so we can maximize our protection each time we apply it and step out into the sun. Here, rules to follow for a safe summer:
Rule #1: Go with an SPF of 15 or Higher
Sun protection factor (SPF) has to do with the amount of time a product protects the skin from the reddening caused by ultraviolet rays, compared to how long it would take without the product. If you would normally burn in 20 minutes, a sunscreen with an SPF of 15 will protect you for 15 times longer, or about five hours.
"Fifteen is probably sufficient for most people most of the time," says Dr. Neil S. Goldberg, a dermatologist who practices in the New York communities of Bronxville and White Plains. "But if somebody has had skin cancer... or burns very easily, they should probably use an SPF of 25 or higher." Goldberg says that anything less than 15 is probably worthless, whether you are sun-sensitive or not.
Past an SPF of 15, the incremental sun-protective benefit diminishes. An SPF of 15 blocks out 93 percent of harmful rays; an SPF of 25 about 96 percent; and an SPF of 30 about 97 percent.
Even if you're not a particularly sun-sensitive person, it may be worthwhile to choose an SPF higher than 15. The level of protection indicated on a product is only reached if the correct amount of sunscreen is used (1 ounce per use is considered optimal). However, most people apply too little, and while it's best to try to use the recommended amount, if you use a higher number SPF, you will get greater protection using less product.
Rule #2: Get Broad-Spectrum Protection
While SPF is a universal measure of protection against UVB rays, known to cause sunburns and many forms of skin cancer, there is currently no standard for UVA rays, which are less potent but more prevalent. UVA rays are thought to play a role in the wrinkling and aging of skin, and may contribute to skin cancer. Some sunscreens now offer what is called "broad-spectrum" protection, or protection against both UVA and UVB rays.
Avobenzone (Parsol 1789) chemically absorbs UVA rays. Some question exists as to whether it becomes less protective when exposed to sunlight. Results of studies to determine this should be available in the next year or two. For now, Dr. Henry W. Lim, chairman of the department of dermatology at the Henry Ford Health System in Detroit, calls avobenzone "the best UVA protection on the market in the U.S."