Ingredients

Azelaic acid

Azelaic acid is a saturated dicarboxylic acid used as a cosmetic ingredient at lower concentrations and as a prescription medicinal active substance at higher concentrations. It is one of the clearer worked examples of an ingredient sitting on the EU cosmetic/medicinal boundary.

At a glance

INCI name

Azelaic Acid; also seen as derivatives, Potassium Azeloyl Diglycinate

Chemical name

Nonanedioic acid; HOOC–(CH₂)₇–COOH

CAS number

123-99-9

Regulatory class

Cosmetic ingredient at lower concentrations under Regulation (EC) No 1223/2009; also medicinal active substance at higher concentrations (typically 15% or 20% in topical preparations), reserved to the pharmacy channel under national medicines law

Cosmetic function

Buffering; skin conditioning (where used cosmetically)

What it is

Azelaic acid is a saturated nine-carbon dicarboxylic acid. It occurs naturally in small amounts in some grains and is produced industrially by oxidative cleavage of oleic acid. In cosmetic formulation, the free acid is poorly soluble in water and is often used as a salt or as a derivative such as potassium azeloyl diglycinate.

How it is used in parapharmacy products

At cosmetic concentrations, azelaic acid and its derivatives are used in leave-on facial products positioned for skin-tone and textural concerns. Concentrations in cosmetic products are typically in the low single-digit per cent range. At medicinal concentrations — usually 15% or 20% in topical creams and gels — azelaic acid is a prescription medicine in most EU jurisdictions, indicated for specific dermatological conditions; the medicinal product is not within cosmetic law and is reserved to the dispensing channels permitted by national law (typically the pharmacy).

Regulatory status

Azelaic acid is not subject to specific concentration restrictions in the Annexes of Regulation (EC) No 1223/2009. The decisive question for any given product is whether, by its presentation and function, it is a cosmetic or a medicinal product. A product presented as treating a disease is a medicinal product irrespective of the concentration of azelaic acid; a product at low concentration, presented for cosmetic functions, and used in a cosmetic vehicle, is a cosmetic.

Medicinal products containing azelaic acid have national marketing authorisations in EU Member States. Their status outside the cosmetic regime means that they cannot be sold by a French parapharmacy. In Italy and Portugal, they may be available in the parafarmacia and local de venda de MNSRM channels respectively only if classified as non-prescription in the national system (typically they are not).

Evidence summary

The evidence base for azelaic acid as a medicinal active substance — within the marketing-authorisation dossier for licensed prescription products — is separate from the cosmetic evidence and is reflected in the indications of those products. Cosmetic evidence for azelaic acid and for its derivatives at cosmetic concentrations is best characterised as limited to dermocosmetic studies of variable quality; the magnitude of any cosmetic effect depends on the formulation, the concentration and the population studied. Cosmetic claims must comply with Regulation 655/2013 and must not present the product as treating disease.

This site does not provide treatment advice. For questions on managing dermatological conditions, the appropriate advice is from a pharmacist or a physician (dermatologist).

Safety and known considerations

Topical azelaic acid can cause transient stinging, burning or erythema, particularly during the first weeks of use. Cosmetic-grade derivatives are typically less irritant than the free acid at the same nominal concentration. As with any active ingredient, the cosmetic product safety report must address the foreseeable conditions of use; for medicinal products containing azelaic acid, the summary of product characteristics (SmPC) and the patient information leaflet (PIL) document the medicinal-product safety profile.

Last reviewed: May 2026.