May 20, 2014 at 3:19 PM ET
When buying sunscreen, most people go right for the SPF (sun protection factor). However, not every sun block that promises a high SPF delivers the full protection — and few work effectively after being submerged in water, according to new research from Consumer Reports.
The Consumer Reports researchers tested 20 sunscreens, finding some products delivered less than half the promoted SPF, while others ranged from 4 to 40 percent below their claims.
Of the 20 tested, Consumer Reports recommends seven sunscreens, which provide "good to excellent" protection against sunburn, as well as blocking the broad spectrum of UVA and UVB rays:
Sunburn is caused by ultraviolet B rays, which are stronger at midday and in the summer. Ultraviolet A rays, which age the skin, can penetrate glass and are the same level all year, all day. Both types can cause skin cancer.
Consumer Reports finds spray sunscreens provide the most effective coverage, although it cautions against lung irritation from inhalation of the chemicals.
The Food and Drug Administration, which tests sunscreens before they are in stores, advises anyone going in the sun to use a broad-spectrum sunscreen with an SPF value of 15 or higher. An SPF over 50 does not equal better sunburn protection, the FDA says. Also, the FDA banned the terms "waterproof" and "sweatproof." Sunscreens labeled as "water resistant" are supposed to remain effective for 40 minutes or 80 minutes when swimming or sweating, based on FDA guidelines.
See the full results of the Consumer Reports sunscreen report (subscription required).