Ingredient guide
Azelaic acid: a guide for sensitive and rosacea-prone skin
Azelaic acid has quietly become one of the most useful actives for the kinds of skin most over-the-counter brands ignore: rosacea-prone, eczema-adjacent, post-inflammatory hyperpigmentation. This guide explains what it does, why it works, and how to use it without triggering a flare.
What is it
Azelaic acid is a naturally-occurring dicarboxylic acid produced by yeast on human skin. In the US, it's sold over-the-counter at concentrations up to 10%, and as a prescription gel (Finacea) at 15%. Our Sensitive Serum is formulated at the top of the OTC range — 10% — in a low-pH, anti-irritant base.
What it does
Three things mostly. First: it's anti-inflammatory, which is why it's a first-line treatment for the papular redness pattern of rosacea. Second: it's a mild keratolytic, which helps with the post-acne pigment that lingers after a breakout clears. Third: it has antimicrobial activity, useful in the bacterial component of rosacea and adult acne.
Who should use it
People with rosacea (especially Type 1 and Type 2), post-acne hyperpigmentation, melasma, and adult acne. People who can't tolerate retinoids often tolerate azelaic acid much better, and the two can be layered safely.
How to use it
Apply a thin layer to clean, dry skin once or twice a day. Most people start at once-nightly and ramp up. If you're also using a retinoid, alternate nights for the first month, then layer (serum first, two-minute wait, then retinoid).
The clinical evidence
Our Sensitive Serum was tested in an 8-week study of 40 rosacea-prone participants. 87% reported reduced visible redness; the mean Investigator Global Assessment improved by 1.2 points. No participant withdrew from the study for irritation, which is the headline metric when we're formulating for reactive skin.