Azelaic Acid

Measured on: inflammatory lesion count (papules and pustules) in papulopustular rosacea, investigator-counted.

The evidence is two identical multicentre double-blind vehicle-controlled 12-week trials of 15% gel twice daily, 329 and 335 patients, in which inflammatory lesion counts fell 58% against 40% on vehicle in one study and 51% against 39% in the other. Both the papers and the approved labelling report that difference at the end of treatment and tabulate week 12 only; the trials had earlier visits but none is published as the first to separate from vehicle, so 12 weeks is a ceiling and onset may well be earlier. A GRADE-assessed systematic review rates the papule and pustule reduction high-certainty, which establishes that the effect is real, not when it appears. Pigment is a slower and separate wait - the melasma work uses 20% cream over roughly six months in Fitzpatrick IV-VI skin - and the 2024 US acne guideline rates azelaic acid only a conditional option. The 10% sold over the counter has never been trialled this way, so this bucket describes prescription strength; stinging in the first weeks is usual and settles.

Thiboutot D, Thieroff-Ekerdt R, Graupe K, 'Efficacy and safety of azelaic acid (15%) gel as a new treatment for papulopustular rosacea: results from two vehicle-controlled, randomized phase III studies', J Am Acad Dermatol 2003, PMID:12789172 - verified against PubMed. FINACEA (azelaic acid) Gel 15% prescribing information, Clinical Studies, which states the vehicle difference at the end of treatment and reports week 12 only. GRADE-assessed systematic review of rosacea interventions, Br J Dermatol 2019, PMID:30585305 (high-certainty evidence for topical azelaic acid on papules and pustules). Acne clause: PMID:38300170 (AAD 2024 acne guideline, conditional recommendation).