Is Glycolic Acid Safe? Concentrations, pH and Skin Safety

What is glycolic acid?

Glycolic acid (INCI: Glycolic Acid) is an alpha-hydroxy acid (AHA) with the smallest molecular weight of all the acids in this group, which means it penetrates the epidermis more deeply than, for example, lactic or mandelic acid. It is derived from sugar cane, but cosmetics mainly use a synthetic form of defined purity.

Glycolic acid works by loosening the bonds between keratinocytes in the stratum corneum, which leads to the exfoliation of dead skin cells. The effects include a smoother skin surface, improved tone, reduced discoloration and stimulation of collagen synthesis.

Regulations: what do the SCCS and the EU Regulation say?

The safety of AHAs, including glycolic acid, has been the subject of several scientific opinions by the SCCS (Scientific Committee on Consumer Safety). The key guidelines for consumer cosmetics are:

• Concentration up to 10% in leave-on products (creams, serums, toners): considered safe at pH ≥ 3.5.
• Concentration up to 4% in rinse-off products (gels, wash-off masks).
• Mandatory warning on AHA products regarding increased photosensitivity and the need to use sunscreen.
• Products for professional treatments may contain higher concentrations and are subject to separate regulations.

The limits above stem from EU Regulation 1223/2009, Annex III item 14, amended by Regulation 2022/1181 for AHAs (the SCCS/1596/18 opinion of 2018 established the 10% / pH ≥ 3.5 limit). The CosIng entry for Glycolic Acid does not include a ban on use, but it does require compliance with the concentration limits.

Why is pH so important?

The concentration value alone is only half the story. The pH of the product is just as important, because it determines how much of the glycolic acid remains in its active, free (undissociated) form:

• At pH 3.5 — about 50% of the acid is in active form,
• At pH 4.0 — about 20% of the acid is in active form,
• At pH 4.5 — about 7% of the acid is in active form.

A product with 10% glycolic acid at pH 5.0 will be much gentler than a product with 5% glycolic acid at pH 3.0. That is why, when buying AHA peels, it is worth looking for information about the pH — not just the concentration. In our peels category we try to take these parameters into account when evaluating products.

Glycolic acid safety for different skin types

Glycolic acid is not a uniformly safe ingredient — its risk profile depends on the skin and the application:

• Normal and oily skin: Tolerates glycolic acid well at concentrations of 5–10% and pH 3.5–4.0.
• Dry and dehydrated skin: May experience irritation at high concentrations — it is better to start at 5% with a higher pH or choose acids with a larger molecular weight.
• Sensitive and reactive skin: Glycolic acid is often poorly tolerated — consider gentler mandelic or lactobionic acid. Compare your options in our ingredient search.
• Atopic and eczema-prone skin: Avoid AHAs during flare-ups. In remission — only at low concentrations and after consulting a dermatologist.
• Skin with rosacea: Generally not recommended — high potential to aggravate inflammation.

How to safely introduce glycolic acid into your routine?

1. Start with a low concentration — 5–8%, pH 3.5–4.0. Test your tolerance over 2–3 weeks.
2. Apply in the evening — glycolic acid increases the skin's photosensitivity; applying it in the morning raises the risk of sunburn.
3. Always use SPF in the morning — SPF 30–50 every day for the entire period you are using AHAs. This is not optional, it is a must.
4. Do not mix it with retinol in the same application — this can lead to excessive irritation. Alternate them instead.
5. Do not apply it to damaged or irritated skin — active inflammation, wounds or burns.

Glycolic acid vs. other AHAs — how to choose?

Glycolic acid is not the only option in the alpha-hydroxy acid group. Alternatives worth considering:

• Lactic Acid — gentler, has moisturizing properties, good for dry skin,
• Mandelic Acid — absorbs more slowly, safer for sensitive skin and darker complexions,
• Lactobionic Acid — a PHA, very gentle, recommended for atopic skin.

You will find more information about individual acids and their safety profiles in the PurScore.pl ingredient encyclopedia. You can also compare specific products in our chemical peels category.

Note: This article is for informational purposes and does not replace a dermatological consultation. If you have any doubts about choosing a peel for your skin type, consult a dermatologist.

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