Azelaic acid belongs to a class of compounds called ‘dicarboxylic acids’. Azelaic acid is believed to decrease the severity of acne, by targeting the root causes; inflammation, the abundance of the bacteria Propionibacterium acnes and the clogging of pores. Furthermore, azelaic acid also decreases the production of keratin, which is a natural substance that clogs the pores in acne leading to the formation of spots1.
The anti-inflammatory effect of azelaic acid has been demonstrated in people with acne vulgaris, in which application of a gel containing 15% azelaic acid was shown to reduce the number of facial pimples2. This effect might be through suppression of molecules involved in the inflammatory response of the skin (for instance the so-called ‘cytokines’ IL-1β and IL-6), when affected by acne3.
A number of studies have investigated the antibacterial properties of azelaic acid showing that 20% azelaic acid can effectively reduce the amount of skin bacteria present in acne1. Furthermore, the prevention of pore clogging and its effect on blackheads has been shown in people with mild-to-moderate acne. In a study, a 20% azelaic acid was reported to alleviate acne severity, and reduce the number of blackheads after 45 days of treatment4.
Because there are several causes of acne (inflammation, presence of the bacteria Propionibacterium Acnes, increased keratin and clogging of the pores) which are not all targeted by one type of ingredient, it is suggested that the anti-acne effect is increased when combining azelaic acid with other ingredients, for instance benzoyl peroxide5.
Finally, a study has shown that azelaic acid can be beneficial6 in reducing post-acne hyperpigmentation (darkness of the skin after acne). In a population of dark skin patients, that are known to be at increased risk of developing post-inflammatory hyperpigmentation, application of a topical gel with 15% azelaic acid gel twice daily for 16 weeks significantly reduced the hyperpigmentation. The mechanism for this effects is most likely caused by its inhibitory effect on the production of melanin, which is the natural pigment of the skin7.
The concentration of an ingredient is important for its efficacy, and therefore products containing the same ingredient may not necessarily have the same effect as in the studies mentioned above.
Updated: July 2017