Glycolic Acid

What is glycolic acid and what does it do?

Glycolic acid is an alpha hydroxy acid originally derived from sugar cane. Its small molecular size lets it penetrate the outer skin layer, where it weakens the bonds between dead cells so they shed more evenly. This smooths rough texture, brightens dullness and can help fade superficial pigmentation over time. At higher concentrations and lower pH, used as an in-clinic peel, it causes controlled exfoliation of the epidermis and may stimulate some collagen production. Daily-use products contain lower concentrations. Because it thins the outer layer temporarily, skin becomes more sensitive to sunlight, so daily sunscreen is essential while using it. [1]

What does the evidence show?

Reviews of glycolic acid peels report improvement in acne, superficial pigmentation, melasma and photoaging, mostly from small comparative and open-label studies. A Cochrane review of topical acne treatments included fruit acids but found low-certainty evidence. Evidence for home-use products is largely from small or manufacturer-supported studies. Results depend heavily on concentration, pH and contact time, so studies are difficult to compare directly.

Who should avoid glycolic acid?

People with eczema, rosacea, active sunburn, broken skin or very sensitive skin should avoid or use with caution. Darker skin types have a higher risk of post-inflammatory hyperpigmentation if irritation occurs, so strengths are introduced gradually. Avoid combining with retinoids or other exfoliants on the same night at first. Stop before laser or peels unless advised.

Is glycolic acid available in Singapore?

Lower-strength glycolic acid is a common cosmetic ingredient in cleansers, toners and serums sold in Singapore. Higher-strength peels are intended for professional use under medical supervision. Limits and labelling depend on concentration and product type, so if unsure about a strong product, check with a doctor or pharmacist before use.

If a dark patch, breakout or irritation is not responding to what you are using, the next step is a diagnosis rather than another product. See the Skin A–Z library for related ingredients.