What Is Azelaic Acid? A Scientific Guide for Acne, Rosacea, and Blemishes
Prepared by Pharmacist Berfin Işık. She is a healthcare professional specialized in pharmacy, with experience in cosmetic ingredients and dermatological formulations. This content is for informational purposes only and does not substitute for medical advice.
Azelaic acid has become one of the most talked-about ingredients in dermatology and cosmetic science in recent years. This naturally occurring acid, which offers an effective and safe solution for stubborn skin problems such as acne, rosacea, and hyperpigmentation, stands out with its multi-mechanistic action. In this guide, we discuss azelaic acid's mechanism of action on the skin, its clinical evidence, and its correct use, in light of scientific data.
What is Azelaic Acid?
Azelaic acid is a nine-carbon saturated dicarboxylic acid. It is found naturally in grains such as wheat, rye, and barley, and is also produced by the Malassezia fungus on the skin. It is typically used in concentrations of 5–20% in cosmetic and dermatological formulations and is FDA-approved for the topical treatment of papulopustular rosacea.
Thanks to its chemical structure, azelaic acid is both oil-soluble and water-soluble, allowing it to penetrate various layers of the skin and simultaneously act on multiple biological targets. This property makes it versatile compared to ingredients with a single mechanism of action. From a pharmacological classification perspective, azelaic acid is described as a rare ingredient with antibacterial, anti-inflammatory, antimelanogenic, and anti-keratinization properties.
How Does it Work on the Skin?
Azelaic acid's multi-mechanism of action on the skin places it in a unique position among cosmetic active ingredients:
- Antibacterial effect: It inhibits bacterial proliferation against Propionibacterium acnes and Staphylococcus epidermidis by disrupting the transmembrane pH gradient. This effect does not carry the risk of developing antibiotic resistance.
- Anti-inflammatory effect: It reduces redness and irritation by down-regulating pro-inflammatory cytokines such as IL-1β and TNF-α. This mechanism plays a crucial role in rosacea and reactive skin.
- Tyrosinase inhibition: It targets blemishes and hyperpigmentation by competitively inhibiting tyrosinase, the key enzyme in melanin synthesis. It works similarly to hydroquinone but with a better safety profile.
- Anti-keratinization: It normalizes follicular hyperkeratinization, preventing pore clogging and comedone formation, thereby facilitating the penetration of topical medications into the skin.
- Antioxidant effect: It exhibits a neutralizing capacity against reactive oxygen species (ROS), reducing oxidative stress and supporting the skin's own defense system.
Effects on the Skin
| Effect | Description |
|---|---|
| Acne Treatment | Antibacterial effect against P. acnes and normalization of follicular keratinization; similar efficacy to topical retinoids, better tolerability |
| Rosacea Control | Reduces erythema and papulopustular lesions by suppressing pro-inflammatory cytokines; superior efficacy compared to metronidazole 0.75% |
| Spots and Melasma | Regulates melanin production by inhibiting tyrosinase; equivalent efficacy to hydroquinone at 20% concentration, safer profile |
| Post-Inflammatory Hyperpigmentation | Targets dark spot marks remaining after acne and rosacea, suppresses melanocyte activity |
| Pore Reduction | Regulates sebum production, cleanses follicular openings, and reduces the appearance of pores |
| Antioxidant Protection | Limits oxidative skin damage by neutralizing free radicals, supports skin radiance |
Scientific Evidence
The clinical efficacy of azelaic acid is supported by extensive randomized controlled trials and systematic reviews.
A comprehensive systematic review published in the Journal of Cosmetic Dermatology in 2023 by King et al. examined 43 randomized controlled trials. Meta-analyses of 20 studies on rosacea revealed that 12 weeks of azelaic acid use significantly improved erythema severity, number of inflammatory lesions, and treatment success compared to placebo. Furthermore, azelaic acid was found to be more effective than metronidazole 0.75% in the treatment of rosacea.
In 16 studies on acne vulgaris, azelaic acid yielded comparable results to topical retinoids in reducing inflammatory and non-inflammatory lesions, while offering better tolerability in some studies. This finding makes azelaic acid a valuable alternative for patients who develop sensitivity to retinol.
In 7 studies on melasma, 20% azelaic acid showed significant superiority over placebo in terms of both severity and global improvement; it demonstrated similar efficacy to hydroquinone but a safer profile for long-term use. The risk of ochronosis (dark pigment accumulation in the skin) associated with hydroquinone is not a concern with azelaic acid.
A mechanism-focused review published in Clinical, Cosmetic and Investigational Dermatology in 2024 linked azelaic acid's anti-inflammatory effect to the modulation of IL-1β and TNF-α signaling pathways, and confirmed that its antimelanogenic effect works via tyrosinase inhibition. The authors also emphasized azelaic acid's selective action profile, highlighting that it targets only overactive melanocytes without affecting normal melanocyte activity.
Who Can Use It?
Azelaic acid is suitable for a wide range of skin profiles. It can be safely used in cases of: acne-prone and pimple-prone skin, those experiencing rosacea and chronic redness, individuals with spot, melasma, or post-inflammatory hyperpigmentation issues, skin prone to fungal acne (Malassezia folliculitis), and those with enlarged pores. It also offers a well-tolerated alternative for individuals sensitive to retinol. While it has a relatively favorable safety profile for use during pregnancy, it is always recommended to consult your doctor before using any cosmetic active during this period.
Who Should Be Cautious?
Those with a known allergy to azelaic acid should avoid using it. In very dry skin or skin with a compromised barrier, mild irritation, burning, or tingling sensation may be experienced initially; in this case, it is recommended to start with a low concentration and not neglect moisturizing. Temporary hypopigmentation has been reported rarely in very fair-skinned individuals at high concentrations; therefore, application specific to the problematic area should be preferred.
How to Use It?
Applying azelaic acid correctly both enhances its effectiveness and minimizes potential irritation. First, gently cleanse and dry your skin. Optionally, you can apply a pH-balancing toner. Then, spread a thin layer of azelaic acid serum over the entire face or problematic areas; general application is recommended, not spot treatment. After the serum is absorbed, use a moisturizer; this step significantly increases tolerance. In your morning routine, always apply SPF 30 or higher sunscreen; even though azelaic acid does not cause photosensitivity, sun protection is critical in spot treatment.
In terms of frequency of use, it can be applied once or twice a day, in the morning and/or evening. For beginners, a single application per day is recommended; as the skin develops tolerance, the frequency can be increased. In terms of combinations, it can be safely used with niacinamide, hyaluronic acid, and ceramides. High-concentration AHA or BHA should be avoided at the same time; if necessary, these actives should be separated into different time slots.
Recommended Products
Frequently Asked Questions (FAQs)
Can azelaic acid be used every day?
Yes, azelaic acid is safe enough to be used twice daily, morning and evening. You can start with once-daily application and increase the frequency as your skin builds tolerance. If you notice irritation, reduce the frequency of use and prioritize moisturizing.
Can azelaic acid be used with niacinamide?
Yes, these two ingredients are highly compatible. Both have anti-spot and anti-inflammatory effects; when used together, they can create a synergistic effect. A toner or serum containing niacinamide and azelaic acid serum can be safely used in the same routine.
Can azelaic acid be used at the same time as retinol?
It is not recommended to use them in the same step. Timed use, such as azelaic acid in the morning and retinol in the evening, offers a more tolerable routine. For sensitive skin, it is advisable to leave at least a few hours between applications. If you experience sensitivity to retinol, azelaic acid can be considered a strong alternative.
When will I see results?
Initial changes in acne and redness can be noticed within 4–6 weeks. For efficacy on spots and melasma to become apparent, 8–12 weeks of consistent use are generally required. During this process, the use of sunscreen directly affects the effectiveness of the treatment.
Is azelaic acid safe during pregnancy?
Azelaic acid is considered among the relatively safe ingredients for use during pregnancy. However, it is strongly recommended to consult your doctor before using any cosmetic active ingredient during pregnancy.
Conclusion
Azelaic acid is one of the rare versatile ingredients among cosmetic actives. It combines antibacterial, anti-inflammatory, tyrosinase-inhibiting, and antioxidant properties in a single formula, offering a comprehensive response to acne, rosacea, spots, and post-inflammatory hyperpigmentation. Its safe profile across a wide range of concentrations makes it a suitable active for many people, including pregnant individuals. With the right product selection, regular application, and sun protection, azelaic acid continues to hold a strong and lasting place in skin routines.
Scientific References
- King B, et al. A systematic review to evaluate the efficacy of azelaic acid in the management of acne, rosacea, melasma and skin aging. J Cosmet Dermatol. 2023;22(10):2785–2810. PMID: 37550898
- Ather S, et al. Azelaic Acid: Mechanisms of Action and Clinical Applications. Clin Cosmet Investig Dermatol. 2024;17:2359–2375. PMID: 39464747
- Capitanio B, et al. A Comprehensive Review of Azelaic Acid Pharmacological Properties, Clinical Applications, and Innovative Topical Formulations. Pharmaceuticals. 2025;18(9):1273. PMID: 41011144
- Searle T, et al. Azelaic Acid in Dermatology: A Review of Its Mechanism of Action. Clin Cosmet Investig Dermatol. 2024. PMID: 41089572
