There are two layers of the skin. The outer layer is called the epidermis and the inner layer, the dermis. Superficial peels (e.g. glycolic acid) produce very superficial injury, confined to the epidermis. Superficial peels can help improve conditions, such as acne and dyschromia. Deeper peels, (e.g. phenol peels) produce injury within the dermis and can reverse moderate-to-severe photo aging and wrinkles. In general, the deeper peels offer the most dramatic results but require longer recovery periods and carry a higher risk of complications