Combat uneven tone and texture with a small but mighty skin-saver: glycolic acid.
What is glycolic acid?
Glycolic acid is one of several alpha hydroxy acids (AHAs), which are naturally occurring chemicals found in foods such as sour milk, sugarcane, apples and citrus fruits. The glycolic acid in skin care, however, is uaually the synthetic form, which is more stable, ensuring better delivery to the skin. (Naturally derived formulas often go rancid or lose their potency faster than synthetic ones.) Glycolic acid's molecules are the smallest and lightest of all AHAs, so they're able to penetrate the skin more easily. "You don't need a major concentration to have long-lasting efficacy," says Pascale Mora, the scientific communications director for Vichy International. Using even a small concentration (three percent or lower) can yield results. With continuous use, glycolic acid can reduce the appearance of wrinkles, improve uneven skin tone and lessen breakouts, leading to younger- and healthier-looking skin.
In the simplest terms, glycolic acid acts as an exfoliant, removing dead skin and stimulating skin-cell renewal. "It helps reduce skin dullness, unclog pores and reveal radiant skin by getting rid of older cells at the surface of the skin," says Eric Dupont, the founder of IDC, a Quebec-based skin-care brand. The results? Glycolic acid leaves skin soft and smooth; over time, it works at the cellular level, boosting collagen production.
Finding your formula
Products containing glycolic acid may cause itchy, tight or red blotches for some people (usually those with sensitive skin). According to Dr. Dennis Gross, a New York City-based dermatologist and the founder of Dr. Dennis Gross Skincare, "Irritation is directly related to the concentration of the acid." But no matter your skin type, Dr. Gross recommends mixing a lower-concentration glycolic acid with other anti-aging ingredients, such as malic and lactic acids, instead of jumping to a higher concentration of glycolic acid on its own. Start with a more quickly absorbed glycolic formula, such as a peel, an exfoliant or a toner, with a concentration of 10 percent or less.
Glycolic acid is most effective when paired with other active ingredients. To fight acne and reduce shine look for a product containing both glycolic and salicylic acids, or brighten an uneven skin tone with a mix of vitamin C and glycolic acid. For an extra dose of anti-aging benefits, pair glycolic acid with either lactic acid, malic acid or lip hydroxy acid, which unblocks pores so that exfoliation is more effective. There's room to play. The two rules to follow? Moisturize your skin generously and apply sunscreen daily. (But you should already be doing that.)
Alpha Hydroxy Acids (AHAs): A group of water-soluable acids—including glycolic, citric, lactic, malic and tartaric acids—that are found in foods and can remove dead skin cells from the surface of the skin.
Glycolic acid: With the smallest and lightest molecules of any AHA, glycolic acid easily penetrates the dermis, making it the most effective AHA for skin-care purposes.
Lactic acid: An AHA derived from sour milk, lactic acid is best known for lightening and brightening the skin.
Malic acid: Found in fruit, particularly apples, this AHA helps minimize the appearance of fine lines and wrinkles.
Salicylic acid: A lipid-soluable beta hydroxy acid best known for its ability to fight acne.
Vitamin C: Also known as ascorbic acid, vitamin C promotes collagen production in the skin and is a potent antioxidant.