What does azelaic acid do for your skin?

Rosacea: where the evidence is strongest

Bottom line: azelaic acid reduces the bumps and pimples of papulopustular rosacea in trials, and it performed at least as well as metronidazole in the studies we reviewed.

The FDA-labeled product is a 15% foam for inflammatory papules and pustules of mild-to-moderate rosacea, and 15% gel and 20% cream are sold in the US for rosacea and acne FDA medical review DermNet NZ overview. In two vehicle-controlled phase III trials of the 15% gel published in the Journal of the American Academy of Dermatology, inflammatory lesions fell 58% and 51% on drug, versus 40% and 39% on vehicle, over 12 weeks.

In a 15-week head-to-head trial, twice-daily 15% gel beat 0.75% metronidazole gel, with a 72.7% versus 55.8% reduction in inflammatory lesions JAMA Dermatology head-to-head trial. A systematic review of rosacea trials reached a similar conclusion, calling azelaic acid at least equivalent to metronidazole.

Melasma and dark spots: moderate evidence, mixed comparisons

Bottom line: azelaic acid is a reasonable option for melasma, with results that look roughly comparable to hydroquinone, but the trials are small and short.

A Cochrane melasma review found 20% azelaic acid more effective than 2% hydroquinone (RR 1.25, 95% CI 1.06–1.48). A 2023 meta-analysis of six randomized trials with 673 patients found it lowered MASI scores more than 4% hydroquinone, with no difference in adverse events or pigment reduction.

The picture is mixed. A melasma evidence review put 20% cream roughly on par with 4% hydroquinone (RR 1.11, 95% CI 0.94–1.32). Long-term safety data for melasma is lacking, and the authors of the meta-analysis call for larger, longer studies.

Acne and the gaps we could not close

Bottom line: azelaic acid is a legitimate topical option for mild-to-moderate acne, but the best numbers come from reviews we could not trace back to primary trials.

A comprehensive review reports lesion reductions comparable to topical retinoids such as adapalene, with better tolerability in some studies. Clinical guidance describes it as useful for both comedonal and inflammatory acne, and combinable with oral antibiotics or hormonal therapy.

We did not retrieve the primary acne trials, so we cannot give you effect sizes or sample sizes. A King et al. systematic review covers acne, rosacea, melasma and aging, but we could not extract its findings, so we are not drawing conclusions from it.

How it works, and what is still a guess

Bottom line: the mechanism is partly understood, but most of it comes from lab and mechanistic work rather than proof in patients.

The FDA review says the exact mechanism in rosacea is unknown. It points to reduced reactive oxygen species, dampened NF-κB signaling, and lower kallikrein-5 activity, which affects how the skin processes the antimicrobial peptide cathelicidin FDA medical review. Reviews add lower IL-1β and TNF-α, antibacterial action, anti-keratinizing effects, and suppression of tyrosinase-related melanin production comprehensive review.

You will see claims that azelaic acid regrows hair. The evidence is thin. The link is inferred from its anti-inflammatory and 5α-reductase effects, not shown in trials, so we would treat it as unproven.

Side effects and when to check in

Bottom line: most people get mild, short-lived local irritation, and the amount absorbed into the body is considered negligible with topical use.

• Common: stinging, itching, or burning, usually mild and transient comprehensive review.
• Stop and contact your clinician if redness, scaling, itching, or burning becomes severe DermNet NZ overview.
• Not recommended for most cases of lentigo maligna, where surgery is preferred DermNet NZ overview.
• Pregnancy and breastfeeding: we did not verify current label language, so check the current US prescribing information before acting on any claim.