Alpha hydroxy acids (glycolic, lactic, mandelic): uses, strength, evidence, and side effects

At a glance

U.S. status

Cosmetic ingredient

Jobs

Surface texture · Dullness · Mild pigment · Keratosis pilaris and body roughness

Watch for

Effect and irritation track concentration and pH together. FDA's guidance for cosmetics is 10% or less at pH 3.5 or higher; peels are a different category with their own file.

Access

Inexpensive; concentration and pH labeling matter more than brand.

Forms and strengths

5–10% leave-on serums and toners (cosmetic)
Lower strengths in cleansers and body lotions
20–70% professional peels

How to use it

Two or three nights a week at 5–10%, not on retinoid nights until tolerated; daily sunscreen is essential. Mandelic acid is gentler for darker or sensitive skin.

Side effects and cautions

Stinging and redness
Increased sun sensitivity
Barrier damage with daily stacking

Get advice first if

FDA advises sun protection with AHA use; avoid on active eczema or rosacea. Compatible with pregnancy at cosmetic strengths.

Regulatory status

Cosmetic ingredients in the U.S.; FDA guidance recommends 10% or less at pH 3.5 or above for consumer products and sun-protection labeling. Some jurisdictions cap concentrations.

In the trends

The over-exfoliation wave and the skin-cycling correction both start here.

Sources on file

These links support the claims above. Reviewed September 1, 2026. Drug labels link to DailyMed searches so the current label is always one click away.