The smallest alpha hydroxy acid, used to smooth rough texture and bring back a brighter-looking surface.
What it is
Glycolic acid is an alpha hydroxy acid (AHA) that lifts away the dull, built-up layer on the skin's surface. Regular use helps skin look smoother, brighter and more even.
Good for
Rough textureDull skinUneven toneFine lines
How it works
Glycolic acid weakens the bonds between dead surface cells so they shed evenly. Its small size lets it penetrate quickly, which makes it effective but also more likely to sting. With regular use it also helps skin hold more moisture.
Ratings
Evidence
4/5
Well studied in peels and daily products for texture and tone.
Gentleness
2/5
Tingling and redness are common, and it increases sun sensitivity.
Formulation difficulty
3/5
Needs tight pH control and acid-resistant packaging.
Cost
1/5
Inexpensive commodity raw material.
Popularity
4/5
Searches rose sharply in 2024 and kept trending into 2025.
Pairs and cautions
Pairs well with
In a routine. Pairing in one formula depends on matching pH windows.
Schedule 6 (Poison) in cosmetics unless it is 5% or less, 20% or less at pH 3.5 or above, or salon-only with WHS labelling; outside these, POISON labelling applies.
United States
No legal limit, but the CIR panel supports 10% or less at pH 3.5 or above for consumer use, and FDA recommends a 'Sunburn Alert' on AHA labels.
ASEAN
Skin products are capped at 10% at pH 3.5 or above, 20% at pH 3.0 or above for professional use, or 30% for use by qualified medical practitioners, and need a sunburn alert at 2.5% or more without sunscreen.
Canada
Above 3%, labels need set warnings including sunscreen advice; consumer products may reach 18% at pH 3.5 or above, while 18–30% or pH 3.0–3.5 is professional use only.
In the lab
Specifications
Typical use level
5–10%0525%
pH window
pH 3.5–42 acid7 neutral10 alkaline
Solubility
Water-soluble
Sensitive to
High pH
5–10% at pH 3.5–4 for leave-on toners and serums; stronger or lower-pH peels belong in salon-only products.
INCI
Glycolic Acid
Also known as
AHA, Alpha hydroxy acid
Origin
synthetic
Lab notes
Solubility and phase
Water phase. Dissolves readily.
Stability
Partially neutralise with sodium hydroxide, ammonia or arginine to set the free-acid fraction, which determines strength. Check emulsion and thickener stability at low pH.
Regulatory, Australia
Listed on the AIIC with AICIS information obligations, and has no EU limit. Poisons Standard Schedule 6 applies in cosmetics unless the product is 5% or less, 20% or less at pH 3.5 or above, or salon-only with WHS labelling.
Claims to take care with
'Exfoliates' and 'smoother, brighter-looking skin' are cosmetic. Include sun-protection advice and avoid wording that implies a medical procedure.
