Glycolic Acid (AHA)

Glycolic acid, derived from sugarcane, is the smallest alpha-hydroxy acid and therefore penetrates the skin most deeply and quickly. At 5–10% in home products it dissolves the bonds between dead corneocytes, instantly smoothing texture and restoring radiance; longer use stimulates glycosaminoglycan synthesis for plumper, firmer skin. It also fades mild hyperpigmentation and improves the absorption of subsequent actives. Its power demands respect: glycolic acid increases photosensitivity, so nightly-only use and morning SPF 30+ are non-negotiable. Beginners or sensitive skin should start at 5% once or twice weekly. Professional peels use 20–70% and belong in trained hands.