Peeling is a cosmetic procedure during which one or more ablative chemical agents (salicylic acid, glycolic acid, phenol, T.C.A., lactic acid, etc...) are applied to the skin's surface to induce keratolysis of a part or the entire epidermis, with or without the dermis. The exfoliation is followed by a regeneration and remodelling of the skin. Chemical peeling can be used to treat various skin conditions, such as acne, seborrhoea, post-inflammatory hyperpigmentation, melasma, acne scars and photoaging. There are three different levels of chemical peeling, which are classified by their depth of skin penetration: superficial/mild, medium and deep peels. Factors affecting the depth of the peel, and therefore the degree of its effects, include the concentration of the chemical substance used, their molecular weight, the number of layers applied, the application time, as well as the patient's skin condition and sensitivity.
A superficial/gentle peel easily removes the horny layer of the epidermis, leading to an acceleration of the cell cycle. At a concentration of 10 to 35%, it is primarily used to deeply cleanse the skin pores, brighten the complexion, improve skin texture and pigment unevenness, combat comedones, revitalise the skin and stimulate blood microcirculation. The medium peel mainly treats pigment disorders, acne and superficial scars, and reduces fine lines at a concentration between 35 and 50%. Faced with these high concentrations, the peel should be performed by specialised and qualified doctors and, in addition, particular precautions must be taken. On the other hand, photoaging of the skin and deep scars or wrinkles require a deep peel at a concentration above 50%. Indeed, following the inflammatory reaction, an increase in the synthesis of fibroblasts and the production of new collagen and elastin fibres is induced.