July 8, 2008 -- Questions about sunscreens are plentiful in the wake of a recent report by The Environmental Working Group (EWG) that gave a failing grade to 85% of the nearly 1,000 sunscreens reviewed. The products gave inadequate sun protection, have ingredients thought to be health hazards, or have not been tested for safety, according to scientists at the Washington, D.C.-based nonprofit research organization.
Consumers are understandably confused, with many questions about sunscreen use.
WebMD posed eight key questions about sunscreens to experts, trying to get a consensus on how best to protect the skin from the sun's harmful rays. While the experts don't agree entirely, their answers can give you good guidance to face the sun safely.
1. Do some sunscreen ingredients and products really work better than others?
"A definite yes," says Rebecca Sutton, PhD, a staff scientist for the EWG and an author of the report.
Two ingredients favored by EWG scientists are zinc oxide and titanium dioxide, for two reasons, Sutton says. "They protect us over this broad range of ultraviolet A (UVA) and UVB." And these ingredients don't tend to break down as easily as other sunscreen ingredients, according to the EWG.
UVB rays cause sunburn and skin cancer; UVA rays cause aging and likely skin cancer. Because both cause damage to the skin, Sutton says, it's important to pick a sunscreen with broad spectrum protection that shields out both types of rays.
Many active ingredients in sunscreens break down in the sun, wiping out protection, according to the report. And some sunscreens only provide protection against ultraviolet B.
Zinc oxide and titanium dioxide are classified by experts as physical blockers, which work by reflecting rays away from the skin. Other sunscreen ingredients, such as oxybenzone, are chemical blockers, which work by absorbing rays and preventing them from penetrating.
"The physical blocking sunscreens are by far the better sunscreens vs. the chemical sunscreens," says Sonia Badreshia-Bansal, MD, a dermatologist in Danville, Calif.
Newer sunscreen formulas include the ingredients avobenzone and Mexoryl SX. "These are considered improvements because they provide excellent UVA and UVB protection," says Dina Began, MD, a physician at Montefiore Medical Center and assistant professor of medicine at Albert Einstein College of Medicine in New York.
Mexoryl (ecamsule), a UVA blocker approved in 2006 by the FDA, was judged as effective in a report on the sunscreen ingredient in a study published in Plastic and Reconstructive Surgery in 2007.
But the EWG found in its literature search that as much as 40% of Mexoryl can degrade within two hours, Sutton says.
Another new sunscreen addition, Helioplex, is a stabilizer used in sunscreens that combine avobenzone (a UVA sunscreen) and oxybenzone (a sunscreen that blocks UVB and some UVA). While they may be more stable, Helioplex products trigger the same concerns from EWG scientists as do other chemical blockers -- the risk of upsetting hormonal balance, Sutton says.
The bottom line: Physical blockers work better on both UVA and UVB rays, according to experts interviewed by WebMD.