Alpha-Hydroxy acids (AHA's) are a type of biological chemical compounds that consist of a carboxylic acid substituted with a hydroxy radical on the adjacent carbon. These acids may be either biologically expressed or synthetic. AHAs are well-known for their use in the cosmetics elaboration, as they act as common moisturizing agents by catching moisture from the air, hence when applied locally they help enhance moisture content and plasticity of the stratum corneum. They also stimulate cell desquamation by minimizing corneocyte adhesion/cohesion and accelerate cell renewal within the basal layer by promotion of epidermolysis, conducing to the production of new collagen,. This explains their use as exfolients and skin smoothing elements.

They are often found in solutions claiming to reduce wrinkles or the signs of aging, and improve the overall look and feel of the skin. They are also applied as chemical peels found in a doctor's office, beauty and health spas and home kits, which usually contain a lower concentration. Their effectiveness is documented.

AHAs - Helpful or Harmful Skin Repair?

AHAs are generally safe when applied on the skin as a cosmetic agent using the recommended dosage. The most common side-effects are mild skin irritation, redness and flaking. The severity usually depends on the pH and the used concentration of the acid. Chemical peels use to produce more severe side-effects including blistering, burning and dermal discoloration, although they are usually mild and disappear a day or two after treatment. The danger is when, through high levels, low pH and excessive exposure times, more than the devitalized skin layers are eliminated, uncovering immature skin cells, blood, nerve or lymphatic systems to damaging effects of the environment.

The FDA has also warned consumers that care should be taken when applying AHAs after an industry-sponsored study found that they can elevate photo-sensitivity to the sun.

Glycolic acid is the most widely used of a group of chemicals compounds known as B1-Hydroxy acids (AHA's) that consist of a carboxylic acid substituted with a hydroxy group on the adjacent carbon. Glycolic acid is usually made from sugar cane. It is fairly well known and recognized the most efficient of the AHAs for cosmetic uses. Glycolic acid speeds the skin remodeling process producing a smoother texture and healthier look.

Lactic acid, derived mainly from milk is considered to be milder and less irritating than glycolic acid, and is therefore considered ideal for people with sensitive skin such as people affected by dry skin ailments. It is advisable to find a proper skin care product that can promote skin repair and relief. Its origins can be traced back to Cleopatra, who purportedly applied sour milk on her skin.