Azelaic Acid

Azelaic acid is a naturally occurring dicarboxylic acid found in grains like wheat, barley, and rye. It has anti-inflammatory, antibacterial, and keratolytic properties, making it effective for acne, rosacea, and hyperpigmentation. It is available over the counter in 10% concentrations and by prescription at 15–20%.

• Kills acne-causing bacteria (Cutibacterium acnes and Staphylococcus epidermidis) • Reduces inflammation — excellent for inflammatory acne and rosacea pustules • Inhibits melanin production — fades post-inflammatory hyperpigmentation (PIH) and melasma • Normalises follicular keratinisation — prevents clogged pores • Antioxidant properties — neutralises free radicals • Safe during pregnancy (unlike retinol and salicylic acid)

Azelaic acid is especially beneficial for: • Acne-prone skin (including fungal acne — it is Malassezia-safe) • Rosacea (reduces redness, papules, and pustules) • Hyperpigmentation and melasma • Sensitive skin (it is very well tolerated) • Pregnant or nursing women (one of the few actives considered safe) It is suitable for all skin types and rarely causes irritation.

• Apply after cleansing and before moisturiser, AM or PM. • Start once daily, then increase to twice daily if tolerated. • Can be used with most other actives: niacinamide, vitamin C, retinol (in different routines). • Do not use with other exfoliating acids (AHA/BHA) in the same session. • It can cause mild itching or tingling for the first few minutes — this is normal and subsides. • Sunscreen is essential — azelaic acid does not increase photosensitivity but PIH prevention requires SPF.

Azelaic acid is one of the few topical ingredients with strong clinical evidence specifically for rosacea. Mechanism relevant to rosacea: Rosacea involves dysfunction of the innate immune response and abnormal cathelicidin peptide processing (specifically LL-37). Azelaic acid reduces LL-37 production, suppresses kallikrein 5 activity (the enzyme that activates LL-37), and directly reduces inflammatory cytokine production in skin cells. Clinical trials: • A 2003 Phase III trial in the British Journal of Dermatology showed 20% azelaic acid gel reduced inflammatory lesions in rosacea by 57% vs. 40% for vehicle at 15 weeks. • A 2004 comparative trial showed azelaic acid 20% gel was comparable to metronidazole 0.75% gel for papulopustular rosacea. • 10% OTC azelaic acid shows meaningful effects for mild rosacea in 8–12 weeks. Practical notes for rosacea use: • Start once daily for 2 weeks before twice daily — rosacea skin is often reactive • Apply to completely dry skin — on damp skin it penetrates more rapidly and may cause more tingling • Combine with gentle ceramide-rich moisturiser and mineral SPF (zinc oxide) • Prescription-strength (15–20%) significantly outperforms OTC for moderate-severe rosacea

Azelaic acid is unique among pigmentation treatments because it works through multiple mechanisms simultaneously. Mechanism: It inhibits tyrosinase (the enzyme that converts tyrosine to melanin), reduces the proliferation of abnormal melanocytes, and has a cytotoxic effect selectively on hyperactive melanocytes — without harming normal melanocytes. This makes it safer for darker skin tones than many alternatives. Comparison with other actives: • vs. Vitamin C: Both inhibit tyrosinase, but azelaic acid is more selective for abnormal melanocytes. Combination of both can be more effective than either alone. • vs. Niacinamide: Niacinamide blocks melanosome transfer rather than production. Combining azelaic acid (reduces production) with niacinamide (blocks transfer) addresses two different points in the pigmentation pathway. • vs. Hydroquinone: Hydroquinone is more potent but banned in EU cosmetics above 0.02%. Azelaic acid at 20% shows comparable efficacy to 4% hydroquinone in clinical trials with better safety profile. • vs. Kojic acid: Similar tyrosinase-inhibiting mechanism. Azelaic acid generally has better clinical evidence and tolerability. For dark skin tones (Fitzpatrick IV–VI): Azelaic acid is one of the safest brightening options because it selectively targets hyperactive melanocytes rather than blanket suppression.

Azelaic acid is available in several formulation types, each suited to different skin types and needs: Gel (e.g., Finacea 15%): Fast-absorbing, mattifying. Best for oily or acne-prone skin. Higher bioavailability than cream formulations. Cream: Richer texture with added barrier-supporting emollients. Better for dry or sensitive skin. Often combined with ceramides or glycerin. Foam: Newer format with enhanced penetration due to small bubble structure. Used in some prescription formulations. Excellent for rosacea. OTC considerations: Most OTC products contain 10% azelaic acid, compared to 15–20% in prescriptions. For mild concerns, 10% twice daily provides meaningful results. For moderate acne, rosacea, or significant hyperpigmentation, prescription strength is clinically superior. Texture and tolerability: Azelaic acid can be slightly drying at higher concentrations. Apply a ceramide moisturiser after application and use barrier-supporting ingredients consistently. The initial tingling on application typically subsides within 2–4 weeks of regular use.