Azelaic acid and azeloyl glycine in cosmetics: what is the difference?
Azelaic acid appears both in pharmacy medicines and in cosmetic serums, while “azeloyl glycine” (Potassium Azeloyl Diglycinate) is a separate, water-soluble ingredient. How to tell them apart on the label and where cosmetics end and medicines begin.
Updated: 31 October 2026 · Reviewed by: Kamil Pyziak
What azelaic acid is
Azelaic acid is a dicarboxylic acid: a short chain of nine carbon atoms with an acid group at each end. It occurs naturally in grains such as wheat, rye and barley and is also produced by yeasts that live on human skin. For industrial use it is made synthetically, typically from oleic acid, a fatty acid found in plant oils.
On an INCI list it appears as Azelaic Acid. It is not an exfoliating acid in the same sense as glycolic or salicylic acid; it is usually discussed separately because of its different properties and its long history in dermatology.
A medicine and a cosmetic ingredient
Creams and gels containing higher strengths of azelaic acid are authorised as medicines in many countries for specific skin conditions. Depending on the country they are available on prescription or from a pharmacy, and they come with a patient leaflet that explains how to use them. Those instructions, and decisions about whether such a product suits you, belong with a doctor or pharmacist.
Azelaic acid is also used in cosmetics, generally at lower levels and with cosmetic claims. The same substance can therefore sit in two very different categories. What decides the category is not the ingredient alone, but the product’s purpose, the way it is presented and the rules it was placed on the market under.
Cosmetics vs medicines: where the line runs
Under EU law, a cosmetic is a product applied to the outer parts of the body to clean, perfume, change the appearance, protect, keep in good condition or correct body odour. A medicine is intended to treat or prevent disease and needs a marketing authorisation based on evidence of quality, safety and efficacy.
In practice this means a cosmetic with azelaic acid may talk about smoother-looking skin, a more even-looking tone or skin that looks less shiny, but it must not claim to treat acne, rosacea or any other disease. If a product makes treatment claims, it should be a medicine. Results from studies on medicinal azelaic acid cannot simply be transferred to a cosmetic with a different strength and formula.
Potassium Azeloyl Diglycinate (“azeloyl glycine”)
Azelaic acid dissolves poorly in water and in most oils. Cosmetic formulas with it are therefore often suspensions or creams with a slightly gritty feel, and it can be difficult to formulate. To get around this, raw-material makers developed Potassium Azeloyl Diglycinate, often marketed as “azeloyl glycine”: azelaic acid combined with the amino acid glycine and turned into a potassium salt.
This derivative is water-soluble and easy to add to gels, toners and emulsions. It is, however, a different molecule. Its own body of research is smaller and largely comes from cosmetic suppliers, so it should not be read as “azelaic acid in a more convenient form” with the same properties.
How to read the INCI list
Look for the exact name. Azelaic Acid means the acid itself; Potassium Azeloyl Diglycinate means the glycine derivative. Some lists include both. You may also come across rarer names such as Azelaic Acid/Butylene Glycol Copolymer, which are polymers made using azelaic acid and serve other purposes in a formula.
Azelaic acid is often combined with ingredients aimed at similar skin types, for example Niacinamide, Zinc PCA, Salicylic Acid or soothing ingredients such as Panthenol. A pure acid placed high on the list in a simple suspension suggests a product built around it; a derivative near the end of a long list is more likely a supporting ingredient.
Practical notes
Products with azelaic acid can cause a temporary tingling, itching or burning sensation, especially at the start or on sensitive skin. If you are already using a medicine for your skin, are pregnant or breastfeeding, or have a diagnosed skin condition, ask a doctor or pharmacist before adding a cosmetic with azelaic acid or similar actives.
Do not use a cosmetic as a substitute for a treatment a doctor has prescribed, and do not combine several products with the same active without advice.
What the label does not tell you
A cosmetic INCI list does not show the concentration of azelaic acid or its derivative, nor the pH or how the formula was tested. A percentage on the front of the pack is a manufacturer’s statement.
The label also does not tell you whether the product is right for a particular skin problem. Persistent redness, spots or inflammation are worth having looked at by a doctor rather than self-treated with cosmetics.