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First across the finish line, in 1995, was Ortho Dermatological's prescription cream Renova, a less concentrated form of its antiacne medication Retin-A. The two are the only products that have been medically proved to reduce fine lines. Their active ingredient, a form of vitamin A called tretinoin, does at least two things: it boosts the development of firm new keratinocytes and smooths tiny creases in the upper layers of the epidermis. The downside: some women find it irritates their skin too much.
Renova's success inspired something of a rush on vitamin A. But instead of using tretinoin--which would trigger intense FDA scrutiny, not to mention a patent-infringement lawsuit--most over-the-counter skin products contain other forms of vitamin A. Although these compounds, technically known as esters, are not biologically active, the theory is that certain enzymes in the skin would convert at least some of them into tretinoin.
Sounds plausible enough until you talk to James Olson, a biochemist at Iowa State University who studies vitamin A's effects on the body. Olson tells us that while these enzymes probably exist, there are no good studies proving that they're powerful enough to make the esters get to work. For their part, cosmetics manufacturers reply that you don't need a lot of enzyme to have an effect. The majority of the products we tested used derivatives of vitamin A, with the highest being L'Oreal's Plenitude at .1%. Dermatologists are divided on whether that's enough.
Fortunately, there's more than one way to slough off a layer of skin. When Cleopatra bathed in sour milk 2,000 years ago, she was actually giving herself a weak chemical peel--in her case with lactic acid. Nowadays she would have plenty of company in that tub. Jayne Singer, 46, a special-ed teacher, found that the stresses of her job helping inner-city Los Angeles teens were taking a toll on her face. She tried toners, pore cleansers, eye creams and masks of egg yolk and witch hazel. Nothing worked. Then she hit upon glycolic peels and fruit acids. She effuses, "They're melting away layers. Of work? Or skin? Who knows?"
We do know that lactic acid is just one of a group of compounds, called hydroxy acids, that can reduce wrinkles. The trick is to get the right concentration. Too much and you burn through too many layers. Too little and there's no effect at all. Even modest amounts irritate the epidermis a little, causing it to swell, which has the benefit of filling out some of those furrows.
So far, no one has found the happy medium. But there have been enough complaints about hydroxy acids that the cosmetics industry financed an independent review, which concluded that the over-the-counter products were safe as long as they didn't contain more than a 10% solution of hydroxy acids. They added one important caveat. Since hydroxy acids heighten the skin's sensitivity to ultraviolet radiation, users should always slop on sunscreen (at least SPF 2, higher if you spend much time outdoors). Aqua Glycolic, which has one of the highest concentrations, is modestly priced and available at your neighborhood Wal-Mart.