The researchers compared the ingredients and the concentration of ingredients with their criteria for adequate UV-A protection. For effective coverage, they said products should contain a combination of more than 2 percent avobenzone and more than 3.6 percent octocrylene with or without ecamsule at 2 percent and/or zinc oxide at more than 5 percent. (A concentration of 7 percent to 10 percent octocrylene is actually better, Wang said.)
''Three or four passed" their test, he said.
Six products, including the most expensive one, contained no active ingredients for shielding UV-A, the authors noted, pointing out that price is not an indicator of protection.
The study received no manufacturer funding, and Wang did not disclose brand names in his report. Previously, he has received research funding from L'Oreal, a sunscreen maker.
The concern over the lack of adequate UV-A protection is justified, said David Andrews, senior scientist at the Environmental Working Group (EWG), which evaluates sunscreens regularly and posts the results.
"We completely agree with the concern raised on the lack of UV-A protection in face cream moisturizers," said Andrews, who reviewed the study but was not involved in it.
EWG and other environmental-health advocates have urged the FDA to finalize regulations for UV-A coverage. In 2007, changes were proposed for sunscreen labels, with a rating system suggested to denote UV-A coverage, but the proposed changes haven't been finalized. The current regulations date to 1978.
Until tighter government regulations spell out what ''broad-spectrum'' coverage actually means, Wang tells consumers who buy moisturizers to study product labels and look for the combination of ingredients outlined in his study.
According to the Skin Cancer Foundation, one of every five Americans will develop skin cancer, the most common form of cancer in the United States.
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