Glycolic acid is a naturally occurring substance that offers many benefits to the skin when used in skin care formulations. In its raw state, glycolic acid is a powder made up of colorless crystals that have no discernible odor.
When used in the preparation of skin care products, glycolic acid is usually produced in a laboratory by combining the chemicals chloroacetic acid and sodium hydroxide. The acid can also be extracted from plants that contain it, including sugarcane, pineapple and sugar beets. Glycolic acid is considered an alpha hydroxy acid or AHA. This group of organic compounds consists of acids derived from plants that have similar chemical structures.
The first use of alpha hydroxy acids for skin care occurred in clinical settings during the 1970s when the substances were tested to determine if they were beneficial for the treatment of psoriasis. This common skin condition is marked by plaques that form on the skin due to a buildup of cells. The early clinical tests showed that AHAs, including glycolic acid, were capable of removing some of the excess cells, resulting in a thinning of the plaques and a reduction of symptoms for psoriasis sufferers.
After years of clinical testing and the use of glycolic acid in strictly natural skin care treatment formulations, the U.S. Food and Drug Administration (FDA) approved AHAs for inclusion in commercially produced skin care and beauty products in the 1990s. Since that time, AHAs have become incredibly popular as ingredients in many different types of skin care formulations. In fact, more than 200 companies in the United States alone produce products that use glycolic acid as an active ingredient.
One of the primary uses of glycolic acid is in products designed for skin exfoliation, a term that refers to removing the outermost layer of dead cells from the complexion. Glycolic acid and other AHAs have the ability to destroy the bonds that hold protein molecules together. Since the skin tissue is mostly made of protein, glycolic acid is effective at eliminating patches of dry or discolored tissue from the skin. The ingredient is found in many over-the-counter formulations that usually contain the acid at 10 to 20 percent strength. Exfoliating products that feature glycolic acid come in many forms, including masks, pre-moistened cotton pads, lotions, creams and serums.
Glycolic acid is also used in clinical settings at strengths of 20 to 70 percent in chemical peels. These treatments remove either the epidermis (the outer layer of skin tissue) or the epidermis and part of the dermis (the middle layer of skin tissue). Chemical peels that contain glycolic acid are used to treat scarring, skin discoloration and signs of aging like fine lines and wrinkles.
In addition to its exfoliative properties, glycolic acid is also a hydroscopic molecule. This means that it attracts moisture from the environment. When used in skin care products, glycolic acid can transfer water molecules from the air into the skin tissue to replenish lost moisture, making it an effective ingredient in moisturizers when used at low strengths.
Studies show that the actions of glycolic acid also assist with boosting collagen production. Collagen is a vital structural protein, which helps the skin tissue remain firm and resist wrinkling. At low strengths, glycolic acid can be used as an ingredient in anti-aging skin care products that are meant to slow down the appearance of fine lines and wrinkles.
As a treatment for skin care disorders, glycolic acid is still sometimes recommended for patients suffering from psoriasis. It is also used to treat the hormone-related discoloration of the face known as melasma. Since glycolic acid has the potential to cause side effects for developing and breastfeeding babies, women who suffer from melasma during pregnancy are advised to not begin treatment with the ingredient until after delivery and the end of nursing. Glycolic acid is also prescribed for eliminating skin lesions like those seen with actinic keratosis and seborrheic keratosis.
Glycolic acid is listed as "Generally Regarded as Safe" by the FDA; however, some people develop irritation from the ingredient. The most common side effects of glycolic acid are redness and minor swelling. For people who develop irritation from glycolic acid, switching to a product of a lower strength will sometimes eliminate the symptoms. Others must avoid the use of glycolic acid entirely.