Glycolic acid is an AHA (Alpha Hydroxy Acid). It's a water soluble acid and an ingredient that increases luminosity of the skin. AHAs work well on the skin's surface to loosen old, dead skin and reveal fresh newer skin. As an exfoliant, it helps shed dead skin cells and reveal the newer, brighter layers underneath by acting on the stratum corneum (the outermost layer of the skin) and improves the reflection of light on the skin. Unlike scrubs, when Glycolic acid is used at the right percentage and when done appropriately, it's a much gentler way to exfoliate the skin. The major advantage of glycolic acid is that it does more than treat breakouts. The ingredient can also tackle hyperpigmentation, dullness, and signs of skin aging, such as lines and wrinkles, without breaking a sweat.