Glycolic Acid is the smallest alpha hydroxy acid (AHA) and one of the most penetrating, widely used in chemical peels and anti-aging skincare to exfoliate dead skin cells, improve texture, and reduce fine lines. The SCCNFP recommends ≤4% at pH ≥3.8 for consumer products as a precautionary guideline (not a regulatory limit). CIR classifies it as "Safe with Qualifications." Effective but requires careful use — increases UV sensitivity and can cause irritation at higher concentrations.
Glycolic Acid (INCI: GLYCOLIC ACID, CAS 79-14-1) is an alpha hydroxy acid (AHA) — a water-soluble organic acid with a hydroxyl group on the alpha carbon. It is the smallest AHA with a molecular weight of just 76.05 Daltons, making it one of the most penetrating AHAs due to its small molecular size. It is registered in the EU CosIng database (#34147) with the functions of exfoliant, skin conditioning agent, and pH adjuster.
Glycolic acid is the most widely used AHA in cosmetics and dermatology. It works by loosening the bonds between dead skin cells in the stratum corneum, promoting their shedding (desquamation) and revealing smoother, brighter skin underneath. At higher concentrations and lower pH, it may penetrate deeper and has been associated with increased collagen production and improvement in fine lines. The CIR Expert Panel classifies it as "Safe with Qualifications" — meaning it is safe when formulated to avoid irritation, used at appropriate concentrations, and accompanied by sun protection advice. Our database identifies glycolic acid in 3,518 products, making it one of the most widely available exfoliating ingredients.
The SCCNFP (now SCCS) evaluated AHAs extensively and recommends glycolic acid at up to 4% concentration with pH ≥3.8 for consumer leave-on products as a precautionary guideline — this is a non-binding recommendation, not a regulatory limit. Over-the-counter products commonly exceed this guidance (5–10% is typical), but higher concentrations carry greater irritation risk. Glycolic acid has significant GHS hazard codes including H314 (severe skin burns) and H361 (suspected reproductive harm) for the pure substance — these apply to the raw material at full concentration, not to diluted cosmetic formulations. Nevertheless, the ingredient requires more careful use than many others in this database.
Glycolic acid dissolves the intercellular "glue" (desmosomes) binding dead skin cells, accelerating their shedding. This reveals smoother, more even-toned skin and helps unclog pores. Its small molecular size allows it to penetrate more deeply than lactic or mandelic acid, making it one of the most potent over-the-counter AHA exfoliants.
At effective concentrations, glycolic acid has been associated with increased dermal collagen and epidermal thickness in some studies. Regular use is associated with improvements in fine lines, photoaging, and skin elasticity. However, results require consistent use over weeks to months, and evidence quality varies across studies.
By accelerating surface cell turnover, glycolic acid can help fade post-inflammatory hyperpigmentation (PIH), sun spots, and melasma. It is often combined with other brightening agents like arbutin, vitamin C, or kojic acid for enhanced results. Effects are gradual and sun protection is essential to prevent re-pigmentation.
Regular exfoliation with glycolic acid smooths rough texture, reduces the appearance of enlarged pores, and improves product absorption. It can also help with mild acne by preventing dead cell buildup that clogs pores. Best results are seen with consistent, moderate-frequency use rather than aggressive daily application.
Suitable for: Normal, oily, combination, and sun-damaged skin. Use with caution on sensitive, rosacea-prone, or compromised skin. Not recommended for very dry or eczema-prone skin without professional guidance. Requires mandatory sunscreen use. Start at low concentrations and build tolerance gradually.
Glycolic Acid carries a SkinSenseDiary safety rating of 4/10 — moderate risk. The CIR Expert Panel concluded it is "Safe with Qualifications" — safe when formulated to avoid irritation, at appropriate concentrations, and with sunscreen advice. The SCCNFP recommends ≤4% at pH ≥3.8 for consumer products as a precautionary guideline. Raw glycolic acid carries multiple GHS hazard codes including H314 (severe burns) and H361 (suspected reproductive harm), though these apply to the pure substance. Increases UV sensitivity — sunscreen is mandatory.
UV sensitivity is real and documented: The SCCNFP confirmed that AHA use increases skin sensitivity to UV radiation. At glycolic acid concentrations of 2.5–4.0% (pH 3.5), studies showed decreased MED and increased sunburn cell production. Broad-spectrum SPF 30+ sunscreen is mandatory when using glycolic acid. The SCCNFP recommends consumer warnings about UV protection during and for one week after discontinuing AHA use.
pH is as important as concentration: The exfoliating effect of glycolic acid depends on both concentration and pH. At a given concentration, lower pH means more free (un-ionised) acid, deeper penetration, and stronger exfoliation — but also greater irritation. The SCCNFP recommends pH ≥3.8 for consumer products. Products below pH 3.5 should be considered higher risk.
GHS hazard codes apply to the raw material: Pure glycolic acid has multiple GHS health hazard codes. At cosmetic concentrations (typically 4–10%) with buffered pH, the risk profile is substantially different. However, the raw material profile explains why this ingredient requires more careful formulation and use than gentler alternatives like lactic acid or mandelic acid.
Start low, go slow: Begin with a low concentration (5% or less), apply 2–3 times per week, and gradually increase frequency as tolerance builds over 2–4 weeks. Signs of over-exfoliation include persistent redness, stinging, dryness, or increased sensitivity. If these occur, reduce frequency or switch to a gentler AHA like lactic acid.
Glycolic acid carries GHS code H361 ("suspected of damaging fertility or the unborn child") for the pure substance. This classification is based on hazard data for the concentrated chemical, not on evidence of harm from diluted cosmetic products. There is no evidence of harm at cosmetic concentrations, and percutaneous absorption at typical use levels appears minimal. However, limited pregnancy-specific data exists for cosmetic glycolic acid use. Many dermatologists consider low-concentration topical glycolic acid (under 10%) to be low risk, but some practitioners advise avoiding strong chemical exfoliants during pregnancy as a precaution. This assessment reflects the absence of proven harm rather than confirmed pregnancy safety. Consult your healthcare provider — gentler alternatives such as lactic acid or physical exfoliants may be preferred during pregnancy.
Start with a gentle, pH-balanced cleanser. Avoid using a cleansing scrub or brush — combining physical and chemical exfoliation can over-irritate the skin. Pat dry before applying glycolic acid.
Apply your glycolic acid product (toner, serum, or peel pad) to clean, dry skin. Best used in the evening to avoid direct UV exposure immediately after application. Start with 2–3 times per week and increase frequency as tolerance builds. Avoid the eye area and broken skin.
Allow the glycolic acid to absorb for 5–10 minutes before layering other products. Follow with a hydrating, barrier-supporting moisturiser containing ceramides, hyaluronic acid, or squalane. This helps offset potential dryness and supports skin recovery.
The SCCNFP confirmed that AHA use increases UV sensitivity. Apply broad-spectrum SPF 30+ every morning, even on cloudy days, throughout the duration of glycolic acid use and for at least one week after stopping. This is not optional — skipping sunscreen while using glycolic acid can cause hyperpigmentation and accelerate photoaging.
The most popular format. Typically 5–7% glycolic acid. Applied with a cotton pad after cleansing. Good for beginners and daily-to-every-other-day use. Brands like Pixi Glow Tonic popularised this format.
Higher concentration (8–15%) for more experienced users. Often combined with other AHAs or hydrating ingredients. Use 2–3 times per week maximum. Apply a thin layer — more product does not mean better results.
Pre-soaked pads or short-contact masks (10–15 minutes). Concentrations typically 10–20% for at-home use. Professional peels can reach 30–70%. Follow instructions carefully — leaving on too long increases irritation risk.
Hydrating and barrier-repairing ingredients that offset glycolic acid's drying potential. Apply after glycolic acid has absorbed. This combination balances exfoliation with hydration.
Helps strengthen the skin barrier, reduce redness, and improve post-inflammatory hyperpigmentation. Can be layered after glycolic acid or used at a different time of day. Some older advice warned against combining AHAs and niacinamide, but this concern has been largely debunked at cosmetic concentrations.
The single most important pairing. Broad-spectrum SPF 30+ is non-negotiable when using glycolic acid. AHA-induced UV sensitivity is well-documented by the SCCNFP. Apply every morning throughout use and for one week after stopping.
Both are potent actives that increase cell turnover and can cause irritation. Using them together in the same routine may cause over-exfoliation, redness, and barrier damage. Consider alternating evenings: glycolic acid on some nights, retinol on others.
Both work best at low pH and can be irritating individually. Layering them simultaneously may overwhelm sensitive skin. Consider using vitamin C in the morning and glycolic acid at night for maximum benefit with minimum irritation.
Combining multiple exfoliating acids increases irritation risk exponentially. Avoid using glycolic acid with other AHAs (lactic, mandelic) or BHA (salicylic acid) in the same routine unless in a professionally formulated product designed for the combination.
Found in 3,518 products in our database. Here are some well-known options. Note: formulations change — always check the current INCI list on the product packaging.
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