Word: vitamins
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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...
...Like vitamin A, vitamin E is found in several forms, with alpha-tocopherol being the most biologically active. Because alpha-tocopherol isn't terribly stable, however, most cosmeceuticals contain derivatives. Although some of these compounds are converted to the active form in the skin, it's unclear whether they have an effect. Even if you find a cream with alpha-tocopherol in it, there's no definitive word on how strong it should be, according to Dr. Karen Burke, a dermatologist who consults for L'Oreal's Helena Rubinstein division. However, Burke's experiments with mice suggest that vitamin...
What about vitamin C? You'd think, since it's a hydroxy acid and an antioxidant, that it would prove ideal. Vitamin C even has a tendency to stabilize vitamin E, which is one reason you so often see the two of them together. Unfortunately, this putative conqueror of the common cold loses its potency rather quickly when exposed...