. The extent of exfoliation with any of the alpha hydroxy acids depends on the type of acid, its concentration, and the pH of the preparations. Glycolic acid inhibits tyrosinase and chelates calcium ion concentration between the cells in the epidermis, which results in exfoliation of the skin.
Over-the-counter glycolic acid is available in concentrations up to 30%, and in professional products up to 70%. Clinically, glycolic acid above a concentration of 30% causes local burning, erythema, and dryness.
However, overuse of glycolic acid among consumers has increased the incidence of skin reactions and hyperpigmentation. Professional-grade products containing up to 70% glycolic acid are widely available on the Internet and without proper guidelines on use and sun avoidance, adverse events and long term scarring are becoming prevalent.
The overuse of acids and overexfoliation of the skin in patients with skin types I-IV is a growing problem as consumers are purchasing more “at-home peels,” peel pads, glow pads, and at-home exfoliation regimens. This overexfoliation of the skin and the resulting erythema induces rapid postinflammatory hyperpigmentation. Consumers then often mistakenly try to self-treat the hyperpigmentation with increasing concentrations of acids, retinols, and/or hydroquinone on top of an already compromised skin barrier, further worsening the problem. In addition, these acids increase sensitivity to UV light and increase the risk of sunburns in all skin types.
Although glycolic acids are generally safe, standardized recommendations for their use in the skin care market are necessary. More is not always better. In our clinic, we do not treat patients with postinflammatory hyperpigmentation from acids or peels with more exfoliation. We focus on repairing the barrier for 1-3 months, which includes use of gentle cleansers and occlusive moisturizers, and avoidance of acids, retinols, or scrubs, and aggressive sun protection, and then using gentle fade ingredients – such as kojic acid, licorice root extract, and vitamin C – at low concentrations to slowly decrease melanin production. Barrier repair is the first and most important step and it is often overlooked when clinicians try to lighten the skin in haste.
Dr. Lily Talakoub and Dr. Naissan O. Wesley and are cocontributors to this column. Dr. Talakoub is in private practice in McLean, Va. Dr. Wesley practices dermatology in Beverly Hills, Calif. This month’s column is by Dr. Talakoub. They had no relevant disclosures. Write to them at.