Glycolic acid has long been a popular ingredient in skin care. According to Linda Walker’s “The Skin Care Ingredient Handbook,” alpha-hydroxy acid (AHA), derived from sugar cane, is a natural exfoliator that can remove dead skin cells, smooth skin texture and combat wrinkles. These qualities have made glycolic acid a particularly ideal ingredient in facial toner.
Applied after cleansing, toner is meant to remove excess makeup, dirt or impurities, as well as balance the pH levels in the skin. Toners can also help prep the skin for additional targeted treatment. According to Milady’s Skin Care and Cosmetic Ingredients Dictionary, glycolic acid helps fulfill these toning duties by sloughing off dead skin cells and improving tone and texture. It is also believed that it is the AHA with greater penetration capabilities because of its smaller molecular weight. Acneic skin can benefit from a glycolic toner, as the key ingredient helps keep pores clear and prevents clogging.
In addition to its exfoliating properties, glycolic acid also brings much-needed hydration properties to a toning formula. It enhances skin’s moisture retention by increasing its ability to bind water. In improving upon skin’s moisture content, it is better able to combat signs of aging, such as wrinkles and fine lines, as well as irritation and excessive dryness.