Azelaic acid for acne, rosacea and dark spots, explained

Azelaic acid is a topical medicine used for acne, papulopustular rosacea and some types of pigmentation, such as melasma and the dark marks left behind by spots. It works in several ways at once: it calms inflammation, reduces acne bacteria and helps keep pores from clogging, which is why it turns up in so many different skin conversations [1][9].

It is also one of the gentler prescription-strength topicals. Most people notice some tingling or stinging in the first weeks, and it is often considered when other options are not suitable, for example during pregnancy. This guide covers what the evidence shows, which strengths count as medicines, how to apply it and how it compares with the alternatives.

Key takeaways

- Azelaic acid is used as a 15% gel (acne and rosacea) and a 20% cream (acne), and off-label for melasma and post-acne marks [1][2][3][9].

- In two large rosacea trials, the 15% gel reduced inflammatory bumps by 51% to 58%, versus 39% to 40% with the inactive gel [4].

- In melasma, a 20% cream gave results similar to 4% hydroquinone over 24 weeks [7].

- Burning, itching and stinging are common early on and usually settle; the labels describe twice-daily use for several weeks before results can be judged [2].

- A doctor reviews your skin, history and any pregnancy plans and decides whether azelaic acid is appropriate for you.

What azelaic acid is and how it works

Azelaic acid is a naturally occurring dicarboxylic acid. Applied to the skin, it acts on several of the processes behind acne and rosacea [1][2]:

• Anti-comedonal: it normalises how skin cells inside the pore grow and shed, so blackheads and whiteheads form less easily.
• Antibacterial: it reduces the acne bacterium on the skin, and long-term use has not been linked to bacterial resistance, unlike topical antibiotics [3].
• Anti-inflammatory: it dampens inflammatory pathways and reactive oxygen species involved in rosacea [2].
• Pigment-modulating: it inhibits tyrosinase, an enzyme needed to make melanin, and acts mainly on overactive pigment cells [1][8].

Only a small amount reaches the bloodstream. The Spanish product information reports that about 3.6% of an applied dose is absorbed through the skin, and plasma levels stay within the range seen from normal diet [2][3].

Strengths: medicine versus cosmetic

There are two main medicinal strengths:

Product	Strength	Authorised uses in Spain	Status in Spain
Gel	15%	Mild to moderate papulopustular acne of the face; papulopustular rosacea	Prescription-only [2]
Cream	20%	Acne vulgaris	Non-prescription medicine [3]

Both are authorised medicines with full product information on the Spanish medicines agency database (CIMA) [2][3]. Melasma and post-inflammatory hyperpigmentation are not listed indications in Spain, so using azelaic acid for those is off-label, a decision for a doctor [9].

Cosmetic serums sometimes list azelaic acid or related ingredients at lower concentrations. They are not the same as the authorised 15% and 20% products, and the trial results in this article come from those medicinal strengths, not from cosmetics.

Azelaic acid for acne

Azelaic acid treats both comedones and inflamed spots. In controlled studies reviewed in 1991, it gave anti-acne results comparable to topical tretinoin, benzoyl peroxide, topical erythromycin and oral tetracycline [1]. In two later randomised trials, the 15% gel was clearly better than its inactive gel, though about 6% less effective than 5% benzoyl peroxide at reducing papules and pustules [2].

The UK NICE acne guideline (NG198) lists topical azelaic acid (15% or 20%, twice daily) combined with an oral antibiotic as one option for moderate to severe acne, and as a monotherapy option for maintenance when a fixed adapalene and benzoyl peroxide combination is not tolerated [10]. Oral antibiotics are something a dermatologist may use in person; you can read more in our acne overview and the azelaic acid acne guide.

Timing: improvement usually becomes visible after about 4 weeks. The product information advises stopping and rethinking the plan if acne has not improved after one month [2].

Azelaic acid for rosacea

Rosacea is where the evidence for azelaic acid is strongest [9]. The Cochrane review of rosacea treatments rated the evidence that azelaic acid works better than placebo as high quality [6].

Key trial numbers:

• In two phase III trials (664 patients in total), the 15% gel reduced inflammatory lesions by 58% and 51%, versus 40% and 39% with the inactive gel. "Clear, minimal or mild" was reached by 61% and 62% of patients, versus 40% and 48% [4].
• Redness improved in 44% and 46% of gel users, versus 29% and 28% [4].
• In a head-to-head trial, the 15% gel reduced lesion counts by 72.7%, versus 55.8% with 0.75% metronidazole gel, but skin side effects were more frequent (25.8% versus 7.1%) [2].
• A systematic review of five trials (873 patients) found azelaic acid at least as effective as metronidazole, but no study showed an effect on visible small blood vessels (telangiectasia) [5].

Expect results after about 4 weeks; the product information suggests reviewing treatment if there is no improvement after two months [2]. For a wider view of options, see our rosacea section, the azelaic acid rosacea guide and our article on rosacea treatments that work.

Azelaic acid for melasma and dark marks

In a 24-week double-blind study of 329 women with melasma, all using broad-spectrum sunscreen, 20% azelaic acid cream gave good or excellent results in 65%, with no significant difference from 4% hydroquinone cream in overall rating, lesion size or pigment intensity [7]. No allergic sensitisation or ochronosis (a bluish-grey darkening linked to long hydroquinone use) was seen with azelaic acid [7].

For post-inflammatory hyperpigmentation after acne, a small 16-week pilot study suggested the 15% gel, applied twice daily, reduced both acne and the dark marks [8]. That is promising but low-level evidence. Daily sun protection remains essential for any pigment treatment, and you can find more context in our article on melasma causes and treatment and our melasma section.

How to use azelaic acid

What the product information describes [2][3] (the prescribing doctor decides how you use it):

1. The skin is washed with water or a mild cleanser and dried first.
2. A thin layer goes on the whole affected area, morning and evening. For the gel, the label describes about 0.5 g (roughly 2.5 cm) for the face.
3. Hands are washed afterwards, and the eyes, mouth and other mucous membranes are avoided.
4. It is not covered with occlusive dressings.

Starting gently. The 20% cream label describes starting once daily, or only at night for the first week on sensitive skin, before moving to twice daily [3]. If irritation appears with the gel, the label describes using less or applying it once daily until it settles, with a short pause if needed [2]. Ask your doctor before changing how you use it.

Patch testing. Many doctors suggest trying it on a small area first on reactive skin, which fits the gradual start the labels describe.

Combining with other products. The labels advise against alcohol-based cleansers, tonics, astringents, abrasive scrubs and peeling agents, especially with rosacea [2][3]. Azelaic acid can be used alone or in combination with other acne treatments [1], but stacking several irritants increases stinging, so a doctor should plan the order and timing.

Consistency. Results depend on regular use for the whole treatment period, and treatment may continue for several months if it is helping [2].

Side effects and safety

The most frequent side effects with the 15% gel are burning, pain and itching where it is applied; dryness, rash and tingling are also common [2]. With the 20% cream, redness, itching and stinging are very common, and irritation, peeling, dryness and lightening of the skin at the application site are common [3]. Local irritation usually improves as treatment continues [2].

Less common or rare effects include contact dermatitis, hives and allergic reactions such as facial or eye swelling [2]. The product information also notes rare reports of asthma worsening after marketing, so tell your doctor if you have asthma [2].

Pregnancy and breastfeeding

There are no adequate controlled studies in pregnancy. Animal studies at many times the human dose showed no adverse effects, and the labels ask for special caution when prescribing to pregnant women [2][3]. Less than 4% is absorbed systemically and it does not raise levels above the body's natural range, but caution is still advised when breastfeeding, and a baby should not touch treated skin [2]. By contrast, NICE notes that topical retinoids are contraindicated in pregnancy [10]. A doctor weighs this for each person.

How azelaic acid compares with other topicals

Medicine	Main uses	Typical strengths	Watch-outs
Azelaic acid	Acne, papulopustular rosacea, off-label pigmentation	15% gel, 20% cream	Stinging early on; caution in pregnancy [2][3]
Benzoyl peroxide	Acne	Combined with adapalene or clindamycin in NICE options	Irritation, sun sensitivity, bleaches hair and fabrics [10]
Adapalene or tretinoin	Acne, comedones	Varies	Irritation; contraindicated in pregnancy [10]
Metronidazole	Papulopustular rosacea	0.75% gel	Fewer skin side effects than azelaic acid in one trial [2][6]
Hydroquinone	Melasma, dark spots	4% cream	Prescription-only in Spain; 60 to 90 day courses, never over 6 months; not advised in pregnancy [11]

In practice, azelaic acid often fits people who want one product for acne plus marks, those with rosacea and sensitive skin, and those for whom retinoids or hydroquinone are not suitable [9].

When to see a doctor

See a doctor promptly, in person if needed, if you notice:

• Swelling of the face, lips or eyes, breathing difficulty or worsening asthma after applying it [2].
• Severe burning, blistering or broken skin that does not settle when you reduce use.
• Painful, deep nodules or cysts, scarring acne, or acne that has not improved after one month of regular use [2].
• Eye symptoms with rosacea (grittiness, redness, light sensitivity), which needs an in-person assessment.
• A dark patch that is changing, bleeding or irregular, which should be checked by a dermatologist in person.

Severe or scarring acne may need oral isotretinoin, and some rosacea needs oral doxycycline; these are managed by a dermatologist in person. Hi Doctor offers topical skin treatments only.

If you'd like a doctor to look at your case, Hi Doctor offers an online consultation with a doctor licensed in Spain, who replies in under 2 hours on average and decides whether a topical treatment is suitable; see how it works. If a prescription is issued, it is issued in Spain and each pharmacy decides whether to dispense it, and the consultation fee is refunded in full if the doctor declines.

Sources

1. Fitton A, Goa KL. Azelaic acid. A review of its pharmacological properties and therapeutic efficacy in acne and hyperpigmentary skin disorders. Drugs. 1991;41(5):780-98. doi:10.2165/00003495-199141050-00007. https://pubmed.ncbi.nlm.nih.gov/1712709/
2. AEMPS, CIMA. Ficha técnica: azelaic acid 150 mg/g gel (marketing authorisation no. 65365). https://cima.aemps.es/cima/pdfs/ft/65365/FT_65365.pdf
3. AEMPS, CIMA. Ficha técnica: azelaic acid 200 mg/g cream (marketing authorisation no. 60159). https://cima.aemps.es/cima/pdfs/ft/60159/FT_60159.pdf
4. Thiboutot D, Thieroff-Ekerdt R, Graupe K. Efficacy and safety of azelaic acid (15%) gel as a new treatment for papulopustular rosacea: results from two vehicle-controlled, randomized phase III studies. J Am Acad Dermatol. 2003;48(6):836-45. doi:10.1067/mjd.2003.308. https://pubmed.ncbi.nlm.nih.gov/12789172/
5. Liu RH, Smith MK, Basta SA, Farmer ER. Azelaic acid in the treatment of papulopustular rosacea: a systematic review of randomized controlled trials. Arch Dermatol. 2006;142(8):1047-52. doi:10.1001/archderm.142.8.1047. https://pubmed.ncbi.nlm.nih.gov/16924055/
6. van Zuuren EJ, Fedorowicz Z. Interventions for rosacea: abridged updated Cochrane systematic review including GRADE assessments. Br J Dermatol. 2015;173(3):651-62. doi:10.1111/bjd.13956. https://pubmed.ncbi.nlm.nih.gov/26099423/
7. Baliña LM, Graupe K. The treatment of melasma. 20% azelaic acid versus 4% hydroquinone cream. Int J Dermatol. 1991;30(12):893-5. doi:10.1111/j.1365-4362.1991.tb04362.x. https://pubmed.ncbi.nlm.nih.gov/1816137/
8. Kircik LH. Efficacy and safety of azelaic acid (AzA) gel 15% in the treatment of post-inflammatory hyperpigmentation and acne: a 16-week, baseline-controlled study. J Drugs Dermatol. 2011;10(6):586-90. https://pubmed.ncbi.nlm.nih.gov/21637899/
9. Searle T, Ali FR, Al-Niaimi F. The versatility of azelaic acid in dermatology. J Dermatolog Treat. 2022;33(2):722-732. doi:10.1080/09546634.2020.1800579. https://pubmed.ncbi.nlm.nih.gov/32730109/
10. National Institute for Health and Care Excellence. Acne vulgaris: management (NG198), recommendations. 2021. https://www.nice.org.uk/guidance/ng198/chapter/Recommendations
11. AEMPS, CIMA. Ficha técnica: hydroquinone 40 mg/g cream (marketing authorisation no. 81390). https://cima.aemps.es/cima/pdfs/ft/81390/FT_81390.pdf