Identity
a dicarboxylic acid (nonanedioic acid, a nine-carbon chain) found naturally in barley, wheat, and rye, and produced on skin by the commensal yeast Malassezia. In skincare it is a small, well-tolerated multi-use active — a single molecule with anti-pigment (tyrosinase-inhibiting), calming, and pore-clearing action. It exists as a lower-strength cosmetic ingredient (often around 10%, or as gentler azelaic derivatives) and as higher-strength prescription medicines (15% gel, 20% cream) for acne and rosacea. For the full readable explanation of what it is and how it works, see the companion guide, what is azelaic acid?
Development & history
- A naturally occurring dicarboxylic acid, studied in dermatology for decades.
- Established as a prescription topical for acne (20% cream) and rosacea (15% gel), with a large randomised-trial base built up across the 1980s–2010s.
- Adopted into cosmetic skincare at lower strengths and as derivatives (such as potassium azeloyl diglycinate) for the appearance of uneven tone, blemishes, and redness.
- Consolidated by a 2023 systematic review (King et al.) pooling 43 randomised controlled trials across acne, rosacea, and melasma.
Mechanism (as proposed)
a dicarboxylic acid with several documented actions in skin: it inhibits tyrosinase (the rate-limiting enzyme of melanin synthesis) preferentially in overactive melanocytes, so it tends to fade a dark spot without lightening the normal skin around it; it scavenges reactive oxygen species (the basis of its calming, redness-reducing use); and it is mildly antimicrobial and normalises follicular keratinisation (relevant to the appearance of breakouts). Its poor water solubility and limited skin penetration make the delivery vehicle central — which is why results are formulation-dependent rather than guaranteed by "contains azelaic."
Related reading
- The full readable guide: what is azelaic acid?
- Where azelaic ranks among the pigment actives, in best ingredients for dark spots and hyperpigmentation.
- Head-to-heads: azelaic vs niacinamide and azelaic acid vs vitamin C.
- The other brighteners it pairs with: niacinamide, vitamin C, alpha arbutin, and kojic acid.
- The non-negotiable base for any pigment work: how to use sunscreen.