Choosing Sunscreen? How to Decode the Labels

Dermatologist explains what SPF numbers really mean, how much protection to use and when
SATURDAY, July 14, 2012 (HealthDay News) -- You may know that it's important to protect your skin when you're outdoors this summer, but you need to know how to pick the correct sunscreen and how to apply it, the American Academy of Dermatology says.
"Consumers can be overwhelmed by the large number of sunscreen products available and because of that they avoid using sunscreen all together, resulting in sunburn and overexposure to the sun's ultraviolet (UV) radiation," dermatologist Dr. Henry Lim said in an AAD news release.
"Dermatologists can provide the public with the information they need to make smart choices when it comes to sun protection, which can help reduce their risk for skin cancer, and keep their skin looking healthy and youthful," he added.
The AAD says you should read the label on sunscreen products and use only those that offer:
  • Broad-spectrum coverage (label may say "broad spectrum," "protects against UVA/UVB" or "UVA/UVB protection").
  • SPF of 30 or higher.
  • Water resistance.
The AAD also recommends that you: re-apply sunscreen every two hours when outdoors; find shade whenever your shadow appears to be shorter than you are; wear protective clothing, including long sleeves, pants, wide-brimmed hat and sunglasses.
An AAD online survey found that many people are still confused about SPF numbers and how to use sunscreen correctly. Only 18 percent of respondents knew that a sunscreen with SPF 30 does not provide twice the protection of an SPF 15, and only 28 percent of respondents who said they sometimes or always use sunscreen reapplied sunscreen every two hours.
UV protection does not increased proportionately with a designated SPF number, Lim said. An SPF 30 screens out 97 percent of UV rays, an SPF 15 screens 93 percent of UV rays, and an SPF 2 screens 50 percent of UV rays, he explained.
Lim also noted that not applying enough sunscreen or not covering all exposed areas may result in a lower SPF than a sunscreen offers.
"For adequate protection, sunscreens are best applied 15 minutes prior to going outside, and re-applied every two hours or immediately after swimming or sweating," Lim said. "Research demonstrates that most people only apply 25 to 50 percent of the recommended amount of sunscreen, which is one ounce for the entire body or enough to fill a shot glass. The relationship between SPF and amount applied is not a linear one. For example, if only half the proper amount of SPF 15 is applied, the actual in-use SPF would be approximately 5, which is then inadequate protection."
More information
The American Cancer Society has more about sun safety (http://www.cancer.org/Cancer/CancerCauses/SunandUVExposure/SkinCancerPreventionandEarlyDetection/skin-cancer-prevention-and-early-detection-u-v-protection ).
SOURCE: American Academy of Dermatology, news release, June 14, 2012