What is a Chemical Peel?
Unlike mechanical exfoliation which physically smooths and lifts dead skin cells off the skin, chemical exfoliants found in chemical peels lower the pH of the skin towards acidic. This acid environment dissolves specific skin components depending on the peel depth. Superficial peels mainly dissolve desmosomes (the keratin, Velcro-like bonds) within the upper epidermis that keep dead skin cells attached to the face and body. Other peeling agents, like alpha hydroxy acids, can also work by overloading cells with calcium ions, causing cell apoptosis (cell death, in the form of predefined cell suicide leading to cellular renewal), which ‘forces’ desquamation. This, in turn, triggers replenishment of new skin cells in the lower layers leading to skin rejuvenation.
These released skin cells don’t leave the skin right away but later ‘peel away’ in the days that follow. The deeper theexfoliation, the more ‘peeling’ is likely. Deeper chemical peels go above and beyond exfoliation. Whereas superficial peels up to 30% salicylic acid have the strength to dissolve desmosomes, deeper peels can cause protein coagulation and cell necrosis (accidental cell death that can be triggered by external threats) in the epidermis and dermis.
This induces inflammation and the wound-healing cascade, leading to the resurfacing of the lower epidermis and dermis stimulating new tissue to improve skin texture and tone. This process reveals a smoother and more radiant complexion. Both types of peels thicken the epidermis, increase dermal volume and stimulate collagen. The result is a smoother and more radiant complexion.
CHEMICAL PEELS DEPTH CLASSIFICATION
Chemical peels were once classified simply as Light (superficial), Medium, or Deep, depending on the depth of penetration of the ingredients used. However, a new categorisation now classifies them as A: Very Superficial through to D: Deep. Light peels exfoliate to various levels of the epidermis. Medium-depth peels treat through the papillary dermis and deep peels to the mid-reticular dermis. Deeper peels require more downtime and increase the chance of side effects, which include photosensitivity, pigment changes and scarring.