Polyhydroxy Acids for Skin Care - What They Are, Who Should Use Them

Millions of women (and men) who use skin conditioners have tried alpha-hydroxy acids (AHAs) to lift off the tired, dry, flaking layers of sun-damaged or winter-weary skin, but many people find them too harsh. AHAs, such as citric acid, glycolic acid, lactic acid, malic acid, and tartaric acids, have to irritate the skin just a little to lift away old cells. For people who find even that little bit of irritation too much, there are polyhydroxy acids (PHAs). Here's an explanation of what they are and who should use them.

The PHAs are really AHAs that do not penetrate quite as deeply into the skin. Gluconolactone and lactobionic acid are two acids that lift tired, dead skin, but because their molecules are larger than the AHAs, they do not penetrate as deeply. Acids that do not go as deep into the skin are less likely to cause side effects, because they work on less skin.

So, are PHAs really better for your skin that AHAs? That depends on your skin type.

Most people won't notice any difference between exfoliants and skin toners formulated with PHAs and exfoliants and skin toners formulated with older, more familiar AHAs. Dr. Mark Rubin, who is both a professor of dermatology at the University of California at San Diego and a practicing clinical dermatologist, published a lecture stating that PHAs penetrate the skin only about 6 per cent less than AHAs.

Dr. Rubin says his research found that gluconolactone is less irritating than the AHA ingredients, but just a little. He did not study lactobionic acid.

Still, that 6 per cent reduction in the penetrating power of the exfoliant may be just what you need if you have mild irritation from your current product. Just be sure that you never purchase any product that contains other irritating ingredients, such as alcohol, camphor, citrus, menthol, mint, or citrus of any kind, and be sure to avoid getting any skin care product in your eyes.