Glycolic acid is an alpha-hydroxy acid (AHA) which is a natural substance applied to the face to break down the top most layer of the skin to reveal a fresh and healthy underlying skin. Dermatologists apply it in concentrations of 20-70% for best effect, although over the counter preparations with 8-10% glycolic acid are great adjuncts to your skin care regime. It is used to improve the skin's appearance and texture, as well as acne and acne scarring, brown spots and melasma, and helps reduces fine lines and wrinkles. I generally recommend a series of 4-6 peels spaced one month apart. After the initial series, a maintenance treatment every 4 or 6 months works well to maintain the benefits.