Azelaic Acid
In plain terms
A gentle acid derived from grains and also made by the skin's own surface yeast. It is used for acne, rosacea, and dark spots, and it is one of the better-tolerated actives, mild enough to be a common pick during pregnancy.
What the evidence shows
Azelaic acid is a dicarboxylic acid that occurs in wheat, rye, and barley and is produced on normal skin by the yeast Malassezia. It calms inflammation, reduces acne bacteria, and fades post-acne marks by easing off pigment production, with prescription strengths of 15 to 20% and cosmetic products around 10%. Safety bodies have looked at it closely and landed in the same place: the Cosmetic Ingredient Review and the EU's SCCS both cleared it for leave-on use, and controlled trials going back decades report good tolerability even on sensitive skin. The most common complaint is mild, short-lived stinging or itching when you first start, which usually settles. It does not raise sun sensitivity the way the exfoliating acids do, and it shows no signal for hormones, reproduction, or cancer. Its pregnancy reputation is part of why dermatologists reach for it: animal studies showed no harm to offspring even at high doses, absorption through the skin is low, and it is a routine choice when other acne actives are off the table. The honest limit is that dedicated controlled trials in pregnant women are thin, so the usual advice is small areas rather than whole-body use.
On the label
Listed as azelaic acid. Cosmetic versions sit around 10%; the 15 to 20% strengths are prescription. No label tricks here, the main practical note is to introduce it slowly if your skin stings at first.