The study, conducted by Environmental Working Group (EWG), a Washington-based nonprofit, looked at over 400 peer-reviewed articles on sunscreen ingredients.
It found that many of the most popular sunscreens break down quickly in the sun or are not blocking many harmful ultraviolet (UV) rays.
Rankings in the July 2007 issue of Consumer Reports revealed a similar problem: not all sunscreens are created equal.
Rather, they found that sunscreens with the same sun protection factor (SPF) ran the gamut from “excellent” to “poor” in their overall ability to block ultraviolet rays.
SPF measures a sunscreen’s ability to block UVB rays. But it says nothing about its strength against UVA rays, an equally damaging form of radiation that causes wrinkles and, more seriously, skin cancer. And unlike UVB rays that cause sunburns, UVA rays do not leave an immediate mark.
“We don’t have a physical, visible way to know if we’re protected against UVA radiation,” says Jane Houlihan, vice president of the Environmental Working Group (EWG). “Your skin looks fine, you’re not burnt, and you could have a massive dose of UV radiation.”
The Food and Drug Administration does not have any regulations on how sunscreens can accurately indicate their level of UVA protection, no quick and easy number like SPF.
Read more information at Newsweek