Azelaic acid is found naturally in grains such as barley, wheat and rye, but can also be produced commercially in the lab. It has several benefits in skincare including as an anti-inflammatory, with evidence showing great results in treating rosacea symptoms (swelling & redness) via this mechanism.
Azelaic also has an anti-blemish activity - firstly, it is an antibacterial which works to kill acne-causing bacteria, P.Acnes. Secondly, it prevents pores becoming blocked by the skin’s natural shedding process, which makes it harder for this bacteria to populate inside the pore to cause a blemish (it needs an oxygen-free environment to thrive).
Studies have also shown azelaic acid to inhibit melanogenesis (production of melanin), so also has benefits in treating hyperpigmentation and post-inflammatory acne scarring. It has good skin tolerability, so can be used to treat more sensitive skin types in concentrations of around 10%.