There are basically 3 types according to the depth: Superficial, medium depth and deep peels. Superficial peels are Glycolic, Salicylic, Kojic, Mandelic, Retinoic acid an different combinations of these, they are used to treat fine lines, remove scarring and blemishes, including pre-cancerous growths, and even help with uneven pigmentation such as age spots, sunspots and freckles. They work great to treat dark spots left behind by acne and even current acne breakouts. TCA is a medium depth peel to treat more severe problems and Phenol peel is a deep peel for deep lines