The Claim: A Sunscreen Chemical Can Have Toxic Side Effects

By ANAHAD O’CONNOR

Sunscreen is supposed to protect skin. But some people suspect that a chemical in sunscreen, absorbed through the skin, may be even more hazardous than the sun’s rays.

The concerns stem from a small body of research indicating that oxybenzone, which blocks ultraviolet light, may mimic the effects of estrogen in the body and promote the growth of cancer cells. One study found that rats eating high doses of the chemical experienced side effects like abnormal uterine growth.

But in March, researchers at Memorial Sloan-Kettering Cancer Center in New York published an independent report examining all the evidence on the subject and concluded that the alarming findings from early animal studies relied on unrealistic dosages. In rat study, for instance, the animals were fed levels of oxybenzone that would never be achieved in humans through normal exposure to sunscreen.

The researchers also reviewed the data on oxybenzone tested on humans. Men and women do seem to absorb small levels through normal sunscreen use, but there was no evidence that it set off hormonal changes. Nor did the researchers find evidence of toxicity. While the idea of a compound in sunscreen being absorbed through the skin may sound alarming, the report’s authors pointed out that this commonly occurs with skin care products.

For those who have reservations, some sunscreens are now made without oxybenzone, though they may not offer the same ultraviolet protection.

THE BOTTOM LINE

Exposure to oxybenzone, through normal sunscreen use, is safe, studies find.