Mexoryl

Mexoryl is not the most notorious drug on the black market. Only a few insiders, most of them women, even know its worth, let alone where to buy it. But it is one of the most ordinary substances ever to be bootlegged. Mexoryl SX, made by the Paris-based skin-care giant L'Oreal, is an illegal sunscreen in this country, one that is thought to be particularly useful in preventing wrinkles.

Called by dermatologists one of the most effective filters of all wavelengths of ultraviolet light, Mexoryl has been used in sunscreen lotions sold in Canada and Europe for more than a decade. But the Food and Drug Administration has not yet approved it.

The reason for the delay is difficult to discern, because the FDA does not comment on drugs going through its approval process. Dr. Darrell S. Rigel, a dermatologist at New York University, however, said safety is not an issue. "It's just bureaucracy," he said.

And so the cognoscenti ask for Ombrelle Extreme ($11), Garnier's Ambre Solaire ($24) or the particularly coveted Anthelios XL by La Roche-Posay ($40 and more for a relatively small tube) at certain drug stores or order it online from Canadian or French pharmacies or even on eBay. Though the FDA does not track down and prosecute those consumers, the purchases are technically illegal.

Representatives of Zitomer and Cambridge Chemists declined to comment.

'I buy it by the case'

"I started buying it from Canada," one 46-year-old New Yorker said about Anthelios, which she has used for three years. The Canadian pharmacy Web site feelbest.com sells a 3-ounce tube for a little more than $20, which is less than half the cost at Cambridge Chemists.

The woman said she finds Anthelios lighter than titanium dioxide sunblocks and less likely to stain her clothes. "I buy it by the case," she said. "It's pretty good stuff."

The demand for Mexoryl is partly driven by one of the strongest motives: vanity. People are getting wise to the idea that UVA rays, less known than sunburn-causing UVB rays, cause classic signs of aging, not only wrinkles but also sagging skin, brown spots and yellow discoloration. And finding a legal sunscreen in the United States that effectively blocks UVA light, which Mexoryl-enhanced products do, is not as easy as it might seem.

Sunscreen labels often advertise "full spectrum" or "broad spectrum" properties, meaning that they block both UVA and UVB rays. But products can make this claim without specifying how well they protect against UVA rays. And because the familiar sun protection factor (SPF) measurements apply only to UVB blockage, consumers have no handy way to gauge the effectiveness of UVA filters.

A 2004 Procter & Gamble study looked at 188 U.S. sunscreens; only 56 percent offered significant UVA protection, though 82 percent claimed to do so.

Part of the problem is that only within the last 10 years have scientists come to understand the biomechanics of UVA damage. "Up until 1995 the thinking was that UVA was not as important as we now know," Rigel said.

So far the FDA has approved only three ingredients protective against UVA: zinc oxide, titanium dioxide and avobenzone (trade name Parsol 1789).

But Mexoryl seems more effective than any of these at protecting against UVA light. In 2000, Canadian and French researchers slathered six brands of sunscreen and sunblock on the backs of volunteers and exposed their skin to a UV sunlamp for 15 minutes. The product containing Mexoryl (along with avobenzone, titanium dioxide and other ingredients) was more than twice as effective in protecting against UVA light as any of the others. The study was published in the Journal of the American Academy of Dermatology.

Mexoryl is very sturdy compared with other UVA filters, which tend to decompose when exposed to sunlight.

It is hard to tell whether Mexoryl will make it to the U.S. market anytime soon. A L'Oreal spokeswoman would say only that the company has "initiated a process of discussion with the FDA."

Doctors say UVA protection in this country has been slow to improve because consumers are not aware of the damage UVA light can do and of how inadequate many "broad spectrum" sunscreens are.

"I take care of some very well-educated people," said Dr. Katie Rodan of Stanford. "But beyond the SPF number, they don't know anything about sunscreen or what UVA light does."