Any topical agent applied to the skin is limited in its function to addressing only the symptoms of internal malfunction. As such, azelaic acid is not capable of altering or “curing” a disorder; it can only treat the symptoms visible on the surface of the skin. While azelaic acid cannot provide a permanent “fix”, because it is safe for long-term treatment, it is an excellent choice in the effective management of certain conditions.

Anything that speeds up the cellular turnover of the skin may cause a “purging” effect. As azelaic acid speeds this turnover, cellular debris that was deeper in the skin is brought to the surface more rapidly, causing the “purge” effect. Considering that it may take up to 8 weeks for a microcomedone to come to the surface, it’s easy to understand how a purge effect can be a natural response to an ingredient such as azelaic acid. However, purging is not always the culprit for changes in the skin after the use of a new topical product. In general, if the skin has a rashy appearance or generalized, diffuse redness, it is a sign of an inflammatory response, not purging.¹ In these cases, it is important to stop using the associated product and consult with your dermatologist or trusted skincare professional.

Unlike retinoids and some other popular skincare ingredients, azelaic acid does not absorb UV and visible light, making it unlikely to cause sun sensitivity. However, if using prescription-strength azelaic acid products, the skin may be thinned as a result of the increased cellular turnover and therefore more prone to UV-induced damage. With daily sunscreen use, azelaic acid is an appropriate addition to many morning skincare regimens, in particular for patients using products unsuitable for daytime use, such as retinoids.

Any chemical, whether an acid, such as azelaic acid, or a base, can cause a chemical burn, known as a caustic burn, on the skin. Whether or not this occurs, depends on the concentration of the chemical and the state of the skin. Sometimes, burning the skin is the intention. Generally, this level of reaction only occurs with professional or prescription products with higher concentrations of azelaic acid and formulated to have a peeling effect. However, if the skin is impaired, otherwise mild concentrations may cause irritation and a burning sensation in the skin. However, compared to other active topical ingredients such as tretinoin or certain exfoliating acids, azelaic acid is generally well-tolerated with adverse effects rare and generally resolving within 2-4 weeks of use.² When considering the use of any prescription or clinical-grade skincare product, it’s important to consult with and follow the usage guidelines of a skincare professional.

Used appropriately, studies suggest azelaic acid is an effective treatment for long-term management of conditions such as acne and rosacea without culminating in a toxic or allergic reaction. Azelaic acid for acne has the additional benefit of not creating antimicrobial resistance, as may occur with the use of systemic and topical antibiotics. Azelaic acid was first approved for use on the skin by the FDA in 1995, which is relatively recent in terms of scientific study. However, the body of research since then suggests that azelaic acid benefits multiple skin conditions, such as a 20% azelaic acid formulation being found to be as effective in the management of acne as 0.05% topical tretinoin and more easily tolerated by the skin.

Although azelaic acid is effective in improving abnormal pigment conditions such as the hyperpigmentation common with acne, or melasma, it is not effective in lightening UV-induced pigmentation such as solar freckles and lentigines (“liver spots”). Regular and continued use of azelaic acid may lighten freckles slightly, but the effect will be much more mild than other interventions. However, long-term use of azelaic acid has not been associated with pigmentation disorders or other negative effects in the skin.³

Azelaic acid helps to lighten the hyperpigmentation that often lingers after an acneic breakout by interfering with melanin production, specifically by inhibiting tyrosinase. In addition, the increased cell turnover created by azelaic acid will aid the skin in shedding the pigmented cells more quickly, making azelaic acid for acne an excellent choice. Acne may also result in a loss of tissue, called an atrophic scar, or in an excess of tissue, or hypertrophic scar. Azelaic acid for acne may improve certain aspects of the appearance of these types of scars, such as texture and color. However, azelaic acid cannot remodel collagen, and thus will have limited benefit to textural scarring from blemishes.⁴ Thankfully, there is a wide range of professional procedures and treatments, from chemical peels to lasers, for the effective treatment of acne-induced scarring.