What Is Alpha Hydroxy?

While alpha hydroxy acids (AHAs) are an ingredient in modern anti-aging skin care products, the use of alpha hydroxy for skin rejuvenation can be traced as far back as Cleopatra, who soaked in milk baths to soften and preserve her smooth, youthful skin. AHA products once were found exclusively through dermatologists and cosmetic procedures such as chemical peels; however, cosmetic companies succumbed to consumer demands and began marketing milder versions of AHA products for salon use. By the end of the 1980s, at-home products with AHAs became available, and by the mid-1990s, mass marketing of AHA anti-aging products took off.

Function

AHAs help rejuvenate and restore the skin by diminishing and removing the undesirable signs of skin aging, such as hyperpigmentation of age spots and liver spots caused by sun exposure; skin roughness; and fine lines and wrinkles. AHAs expedite the skin's natural exfoliation process. The loosened and dissolved cells of the skin's outermost layer are shed, revealing fresher, more even-toned and, therefore, more youthful skin.

Types

The most common AHAs in skin care products are glycolic acid and lactic acid. Glycolic acid comes from sugar cane. Dermatologists use it for chemical peels, since it penetrates the skin well, offering immediate effects on texture and appearance. While dermatologists use glycolic acid concentrations of 20 percent to 70 percent, home products offer concentrations of 10 percent or less. Concentration and pH level (acidity) determine glycolic acid's potency. Lactic acid, found in milk, also is used as an exfoliant, and it increases skin-cell turnover and hydrates the skin for a rejuvenated complexion. Lactic acid is gentler and can be used for more sensitive and allergy-prone skin. Other AHAs include malic acid, citric acid and tartaric acid, all found in fruits. Using citrus fruits to "bleach" freckles and moles has been a home remedy for centuries.

Effects

The intensity of the effects of AHA skin care treatments depend on the skin's condition, the concentration and pH level of the AHAs, and the frequency of treatment or application. Chemical peels performed by dermatologists who use high concentrations of AHA will have more dramatic effects, reducing the appearance of age spots, fine lines and wrinkles, scars or stretch marks. At-home skin care products have lower levels of AHA concentration and require more frequent and continual application for significantly visible effects (unless the user in his or her 20s, when aging effects are minimal and a simple revitalization of the complexion is all that is desired). For pH levels, the lower the number, the higher the acidity. The ideal pH level for at-home AHA use is 3.5 or higher.

Warning

Don't forget that AHA is an acid and has the power to irritate the skin and leave it stinging, itchy and red. Be cautious about home chemical peels, and seek the advice and services of dermatologists. AHA concentrations for home-use products should be less than 10 percent, and whatever the product is, test it on a small patch of skin before use. While AHA can reverse the signs of aging, it leaves the skin much more sensitive to the sun's ultraviolet rays. Be particularly cautious about using high-strength SPF sunscreens and wearing wide, brimmed hats to protect your face from the sun.

BHAs

Beta hydroxy acids are the close-kin competitors of AHAs in the skin care market. Salicylic acid--the same substance found in aspirin--is a BHA. BHAs share some of the same properties of AHAs, including anti-inflammatory qualities, but they are far less potentially irritating to the skin and can be useful at much lower concentrations. Skin care products with BHA, or even chopped-up aspirin itself, are recommended to resolve blemishes. Like AHAs, though, BHAs cause more susceptibility to sun damage.

References

• "Alpha Hydroxy Skin Care: Smooth Sailing or Rough Seas?" US FDA Consumer article, May 1999
• Glycolic Acid

Resources

• Lactic Skin Care
• The E-Learning Skin Care Resource Center
• Shop Skin Care Products, View Best-Sellers