Glycolic Acid

Glycolic acid is a potent alpha-hydroxy acid exfoliant typically used around 5–10% in leave-on products (and higher in peels), where clinical experience and patch-testing literature consistently show frequent stinging, erythema, and barrier disruption—especially in eczema-prone or compromised skin. Its small molecular size and activity at low pH increase penetration and irritation risk, and cumulative use with other actives (retinoids, benzoyl peroxide, vitamin C, other acids) further raises the likelihood of clinically significant irritation. For patient safety in sensitive populations, it warrants a very high irritancy rating unless carefully buffered, introduced slowly, and used under guidance. Safety Notes: In consumer skincare, glycolic acid appears at very low levels (~0.1–1%) in gentle daily toners/cleansers and “acid blend” products where it functions as a mild exfoliant/pH adjuster. Standard leave-on exfoliants commonly sit around 5–10%, while high-strength OTC peel pads/at-home “chemical peel” solutions marketed to the general public reach ~20–30% glycolic acid (higher strengths are typically professional-use or otherwise restricted). Rinse-off formats can tolerate similar labeled percentages but with reduced exposure time; for leave-on products, effective high-strength use is strongly dependent on low pH and appropriate neutralization/buffering.

Suitability