What Is Exfoliation?
Exfoliation is the process of removing accumulated dead skin cells (corneocytes) from the skin surface, either by chemical dissolution of the intercellular bonds holding them together, or by mechanical abrasion. When the natural desquamation process slows — due to age, dehydration, sluggish cell turnover, or certain skin conditions — dead cells accumulate, causing dull, rough, uneven-textured skin and reducing the efficacy of applied skincare. Controlled exfoliation accelerates clearance of this layer.
Chemical Exfoliation
Alpha-hydroxy acids (AHAs: glycolic, lactic, mandelic acid) work at the skin's surface, breaking down desmosomes holding dead cells together and improving moisture retention. Beta-hydroxy acids (BHAs: salicylic acid) are oil-soluble, penetrating into follicles to dissolve sebum and clear congestion — making them ideal for acne-prone skin. Polyhydroxy acids (PHAs: gluconolactone) are gentler, suitable for sensitive skin, with similar surface-exfoliating action and added antioxidant benefits.
Physical Exfoliation
Scrubs, exfoliating brushes, cleansing devices, and cloths physically abrade the skin surface. When formulated with uniform, non-sharp particles (round beads, sugar, konjac), physical exfoliation can be gentle. Harsh scrubs with jagged particles (walnut shell, apricot kernel) can cause microtears, increasing inflammation and sensitivity.
How Often to Exfoliate
Most skin types benefit from 2–3× per week chemical exfoliation. Sensitive or reactive skin may tolerate only 1× weekly. Over-exfoliation destroys the acid mantle, depletes the lipid barrier, and triggers inflammation — less is consistently more effective.
Signs of over-exfoliation: Persistent tightness, redness, sensitivity to previously tolerated products, and a shiny, tight, "stripped" appearance all indicate barrier damage from excessive exfoliation.
See Acids: AHA, BHA & PHA and Desquamation.