Oxybenzone

In Europe, sunscreens are classified as cosmetics, but in the U.S., they are classified by the U.S. Food and Drug Administration as drugs. According to the FDA, any product intended to prevent, cure, treat, or mitigate disease or to affect a structure or function of the body comes within the definition of a drug. Read the label of your sunscreen, and it will most likely state: Regular use may help reduce premature aging of the skin and some types of skin cancer, due to long-term overexposure to the sun. Some types of skin cancer is an appropriately vague choice of words. Sunscreens may protect against basal cell carcinoma and squamous cell carcinoma, but it is not clear whether sunscreens protect against melanoma, the deadliest form of skin cancer. (See HealthFacts, June 1998.)

Early this year, unanswered questions about the safety of oxybenzone, the principal ingredient in most sunscreens, generated a flurry of letters to the editor of the British journal, The Lancet. It is typically assumed that there is little or no absorption of a product applied to the skin. But Cameron Hayden and colleagues at the University of Queensland, Australia, found that significant amounts of oxybenzone is absorbed by the human skin and subsequently excreted in the urine. They published their finding last year in The Lancet (9/20/97), noting that this result is consistent with earlier lab experiments and animal studies. Dr. Hayden and colleagues concluded, It would be prudent not to apply oxybenzone to large surface areas of skin for extended and repeated periods of time, unless no alternative protection is available. There may be additional concern for young children who have less well-developed processes of elimination and have a larger [skin] surface area per body weight than adults, with respect to systemic availability of a topically applied dose.

Little is known about the safety of repeated applications of sunscreens, according to Dr. Hayden and colleagues. And this concern was underscored by Colin S. Ong of Australias University of Sidney, who observed in a letter to the editor of The Lancet (1/10/98) that sunscreens are often used throughout the year, particularly on the face where the absorption is 2-13 times that of the skin of the forearm. Dr. Ong noted that we know little about oxybenzones long-term biological effects. Clearly, more research is needed because sunscreens have a proven role in protecting against sunlights damaging effects.

Current FDA oversight of sunscreens is largely confined to ensuring that sunscreen can prevent sunburn and that the manufacturers labeling claims are supportable. As with prescription drugs, there is no requirement for the manufacturers to determine long-term safety. Its difficult to get information from the FDA, whose press office barred any direct interview with the appropriate official. But faxed documents indicate that sunscreens did not go through any testing similar to that required of prescription drugs. One document, dated August 25, 1978, states that oxybenzone had been declared safe and effective by a panel of experts. Presumably, the panel of experts was working with even less research information than is available today.

What To Do?

Until we know more about the safety and efficacy of sunscreens, the answer seems to be: Dont rely on sunscreens alone. As noted in last months HealthFacts, heres the prevailing medical advice: Avoid prolonged exposure to the sun, especially between 10:00 a.m. and 2:00 p.m. when its strongest, and wear a broad-brimmed hat and as much protective clothing as possible. Clothes made with special sun-blocking fabric are not worth the extra expense, according to the May 1998 issue of Consumer Reports. CR assessed two fabricsSolumbra and Solarweavemade of tightly woven nylon which purportedly blocks the sunlight. Shirts made of these special fabrics were compared with several shirts made of cotton and polyester. Shirts made of the special fabrics were as good as sunscreens with sun protection factors of 30 and up. But CR found that this was also true of two of the regular shirts (the long-sleeved Lands End Super-Tee and the Hanes Beefy-T).

COPYRIGHT 1998 Center for Medical Consumers, Inc.
COPYRIGHT 2000 Gale Group