What is azelaic acid used for in skin care?

Rosacea is the approved use, and the best-supported one

If you have rosacea bumps or pimples, this is the use with the clearest regulatory backing. The FDA label covers the 15% gel for the inflammatory papules and pustules of mild to moderate rosacea (FDA prescribing label, 2020).

A systematic review of 43 randomized trials found that erythema severity, inflammatory lesion counts, overall improvement and skin clearance all improved versus vehicle after 12 weeks (systematic review of azelaic acid trials). In a head-to-head comparison, it also beat metronidazole 0.75% on erythema, overall improvement and lesion counts.

The label is narrower than the marketing. It says efficacy against redness without papules and pustules has not been evaluated, so redness alone is not the target it was tested for (FDA prescribing label, 2020).

Acne is established, but the labeling details are fuzzy

Acne is the other use with real trial support. Across 16 acne studies, azelaic acid appears more effective than vehicle for global assessments and acne severity (systematic review of azelaic acid trials). The 20% formulation also cleared more lesions than erythromycin gel.

Against adapalene 0.1% gel over 12 weeks, efficacy was comparable, and adapalene was slightly better tolerated (comprehensive review of azelaic acid).

The regulatory picture is less tidy. One review says the FDA approved the 15% gel for rosacea and the 20% cream for acne (comprehensive review of azelaic acid). An FDA review memo describes the acne and rosacea products differently (FDA review memo, NDA 207071). We could not confirm the acne labeling against an FDA label, so check current prescribing information before you rely on it.

Melasma is promising, but the hydroquinone data are mixed

Melasma is where the 20% cream looks promising. Across seven melasma studies, it beat vehicle on severity and global improvement (systematic review of azelaic acid trials).

The hydroquinone comparison is where sources disagree. The systematic review reports that 20% azelaic acid beat hydroquinone 2% on global improvement (systematic review of azelaic acid trials). A separate review calls it similar to hydroquinone, with a favorable safety profile (comprehensive review of azelaic acid). Both cannot be the full story, so read the primary trials before quoting either.

Melasma use does not appear to be on the US label for the 20% cream, but the sources we retrieved do not say so explicitly, so treat that as unverified. Post-inflammatory hyperpigmentation appears on the same list of indications, but the evidence behind it is thinner. For skin aging, the systematic review concludes that randomized trials are still needed.

Safety, dosing and the gaps

Tolerability is the main trade-off. In an FDA review of three US rosacea trials, 788 people used the 15% gel twice daily for up to 15 weeks (FDA review memo, NDA 207071). The most common treatment-related side effects were:

• Burning, stinging or tingling: 29%
• Itching (pruritus): 11%
• Scaling, dry skin or xerosis: 8%
• Erythema or irritation: 4%

Systemic exposure looks low. Plasma levels in rosacea patients on the 15% gel ran 42 to 63.1 ng/mL, while vehicle-only patients ranged from 24.0 to 90.5 ng/mL, so the ranges overlap (FDA prescribing label, 2015). The label directs a thin layer twice daily (FDA prescribing label, 2020) and reassessment if there is no improvement after 12 weeks (FDA prescribing label, 2015).

Weaker uses and what the mechanism explains

Azelaic acid is a nine-carbon dicarboxylic acid that the yeast Malassezia naturally produces (PubMed review of mechanisms). It is described as antibacterial, anti-keratinizing, antimelanogenic, antioxidant and anti-inflammatory. Its melanocyte-inhibiting effect underlies its use for pigment problems (multiple-uses review in dermatology). The FDA label, however, says the mechanism in rosacea is unknown (FDA prescribing label, 2015).

Other reported uses include hidradenitis suppurativa, male pattern hair loss, perioral inflammation, psoriasis vulgaris and keratosis pilaris (multiple-uses review in dermatology). Those rest on mechanism and small studies, not the randomized trial base behind acne, rosacea and melasma, so do not treat them as established. For the broader picture, see our azelaic acid topic hub.