Chemical Exfoliation and Chemical Peel Application
Chemistry that drives the answer
Peel strength depends on acid identity, concentration, pH, free acid value, and contact time - not concentration alone. A lower pH means more free acid and deeper penetration. Alpha hydroxy acids include glycolic (smallest molecule, fastest penetration), lactic, mandelic (largest, best tolerated in deeper skin tones), tartaric, malic, and citric. Beta hydroxy acid means salicylic, which is lipid soluble and follicular. Medium-depth agents include trichloroacetic acid and Jessner solution. Know which peels require neutralization - glycolic and lactic do; TCA is self-neutralizing.
Protocol
Cleanse, degrease with acetone or alcohol where indicated, protect the eyes, and apply in a consistent order with timing. Watch endpoints: tingling and uniform erythema are expected; intense burning, blistering, or frosting means stop and neutralize or rinse. Follow with cool compresses, barrier support, and strict sun protection. Give written aftercare: no actives, no waxing, no heat, no picking, and sunscreen daily.
Contraindications and complications
Avoid active infection, open lesions, sunburn, recent waxing or dermabrasion, pregnancy for salicylic acid, keloid history, and recent isotretinoin. Herpes-prone clients need antiviral prophylaxis arranged through a physician. Complications include post-inflammatory hyperpigmentation, herpes outbreak, burns, and scarring - all of which are documentation and referral events.
Traps: equating higher percentage with deeper peel; forgetting to neutralize a glycolic peel; peeling over an active cold sore; failing to degrease so the acid sits on oil instead of skin. Rule of thumb: when in doubt, use a lower concentration for a shorter time - you can always build, but you cannot unpeel.