Azelaic acid (AA) is a naturally occurring dicarboxylic acid found in grains like wheat, rye, and barley. It is also produced by a yeast that lives on human skin. AA is widely used in dermatology for its ability to address several skin concerns. It is highly regarded for fading the discoloration that lingers after a blemish heals, helping to restore a more uniform complexion.
Understanding What Azelaic Acid Treats
Many people refer to any mark left by a pimple as an “acne scar,” but a distinction must be made between true textural scars and post-inflammatory marks. True acne scars, such as atrophic (pitted) or hypertrophic (raised) scars, involve a loss or excess of collagen. These textural imperfections are generally resistant to topical treatments like azelaic acid and often require in-office procedures.
Azelaic acid is highly effective for the two most common types of post-acne discoloration: Post-Inflammatory Hyperpigmentation (PIH) and Post-Inflammatory Erythema (PIE). PIH appears as brown or dark spots resulting from an overproduction of melanin following inflammation. PIE presents as persistent flat pink or red marks caused by damage or dilation of small blood vessels near the skin’s surface.
AA targets these pigmentary and vascular concerns without the side effects often associated with harsher actives. It addresses the discoloration that most commonly follows an acne breakout, which is distinct from treating the physical indentation or elevation of a true scar.
How Azelaic Acid Targets Skin Discoloration
Azelaic acid targets the dark spots of PIH by acting as a competitive inhibitor of the enzyme tyrosinase. Tyrosinase is the enzyme responsible for producing melanin, the pigment that causes dark spots. By interfering with this enzyme’s activity, AA slows the production of excess pigment in melanocytes triggered by inflammation.
This inhibitory action is selective, targeting only hyperactive melanocytes and leaving normal skin cells unaffected. This mechanism helps fade existing dark spots without causing generalized lightening of healthy skin. The compound also gently encourages cell turnover, helping the skin shed pigmented cells more quickly and improving overall texture.
For the red marks of PIE, azelaic acid leverages its anti-inflammatory and antioxidant properties to calm the skin. Inflammation is the underlying cause of PIE, leading to persistent redness from dilated capillaries. AA reduces this redness by inhibiting the production of reactive oxygen species (ROS) and lowering levels of inflammatory mediators in the skin.
Clinical studies show that AA significantly decreases the intensity and size of PIE lesions, reducing the hemoglobin content responsible for the red color. Furthermore, AA possesses antibacterial properties against C. acnes bacteria and helps reduce keratin buildup. This action prevents new lesions from forming, which is an indirect way to stop the formation of future post-acne marks.
Incorporating Azelaic Acid Into Your Routine
Azelaic acid is available in various strengths and formulations, including over-the-counter (OTC) and prescription options. OTC products typically contain 10% or less, effective for mild discoloration and general skin brightening. Higher concentrations, such as 15% and 20%, are generally reserved for prescription use for moderate to severe cases of discoloration or acne.
When starting AA, introduce it slowly into a simple routine. Apply the product to clean, dry skin once or twice daily, depending on concentration and tolerance. Allowing the skin to fully dry after cleansing can help minimize the initial tingling sensation some people experience.
AA is highly compatible with many other common skincare ingredients, including retinoids, niacinamide, and various humectants. It is available in different textures, such as gels, creams, and foams, with gels often preferred for oily skin types. Due to its mild exfoliating and anti-inflammatory benefits, AA is a flexible addition to both morning and evening routines, but a broad-spectrum sunscreen must be worn daily for optimal results.
Expected Results and Potential Side Effects
The fading of post-inflammatory marks requires patience and consistency. While some users may notice initial improvements in redness and overall skin smoothness within four to eight weeks, significant fading of hyperpigmentation (PIH) generally takes longer. For established dark spots, users should expect to use azelaic acid consistently for three to six months to see the full therapeutic effect.
Azelaic acid is generally well-tolerated, even by individuals with sensitive skin or conditions like rosacea. However, common side effects, especially when first starting use, can include mild burning, stinging, itching, or tingling at the site of application. These initial sensations are usually temporary and tend to subside as the skin adjusts to the treatment, often within the first few weeks.
To mitigate these potential side effects, you can “buffer” the application by applying a layer of gentle moisturizer before or immediately after the azelaic acid. If irritation persists, reducing the frequency of application to every other day can help build tolerance. Although uncommon, more severe reactions like blistering or crusting should prompt immediate discontinuation and consultation with a healthcare professional.