Azelaic acid is one of the more effective and well-tolerated treatments for acne, working against both the bumps you can see and the inflammation underneath. It kills acne-causing bacteria, unclogs pores, fades dark marks left behind by breakouts, and does all of this with fewer side effects than many alternatives. Available in concentrations ranging from 10% over the counter to 20% by prescription, it treats both comedonal acne (blackheads and whiteheads) and inflammatory acne (red, swollen pimples and pustules).
How Azelaic Acid Fights Acne
Azelaic acid works through three distinct pathways, which is part of what makes it so versatile. First, it directly kills the bacteria responsible for acne breakouts. The compound is actively transported into bacterial cells, reaching concentrations over 90 times higher inside the bacterium than in the surrounding skin. Once inside, it disrupts the cell’s ability to maintain normal pH and metabolic function. Even at low concentrations, azelaic acid reduces bacterial protein production by more than 50%. It also has activity against staph bacteria that can complicate acne-prone skin.
Second, it reduces inflammation directly, not just by clearing bacteria but by lowering the production of inflammatory signals in the skin. This is why red, angry-looking breakouts calm down relatively quickly with consistent use.
Third, azelaic acid is keratolytic, meaning it prevents the abnormal buildup of skin cells inside hair follicles. This buildup is the root cause of clogged pores, so by keeping follicles clear, azelaic acid addresses acne at its source rather than just treating what’s already appeared on the surface.
What the Clinical Results Look Like
In controlled studies, 20% azelaic acid cream reduced papules and pustules (inflamed, raised bumps) by 72% after three months, compared to 47% with a placebo cream. Pustules responded slightly better than papules, but both types showed significant improvement over placebo.
For comedonal acne, the timeline is a bit longer but the results are strong. A 20% concentration reduced comedone counts by about 40% after one month and 70% after four months. In head-to-head testing, 20% azelaic acid cream performed equally well as 0.05% tretinoin cream for reducing comedones and overall treatment response. That’s notable because tretinoin is considered a gold-standard topical for acne.
Combining azelaic acid with other treatments boosts results further. When paired with benzoyl peroxide gel, clindamycin gel, or tretinoin cream, both inflammatory and noninflammatory lesion counts dropped more than with azelaic acid alone. Patient satisfaction ratings also improved with combination therapy.
The Bonus: Fading Post-Acne Dark Spots
One of azelaic acid’s biggest advantages over other acne treatments is its ability to treat post-inflammatory hyperpigmentation, the dark or discolored marks that linger after a breakout heals. These marks can persist for months and are often more bothersome than the acne itself, especially on darker skin tones.
Azelaic acid is a competitive inhibitor of tyrosinase, the key enzyme that drives melanin production. What makes it particularly useful is its selectivity: it targets overactive, abnormal melanocytes (the cells producing excess pigment) without affecting normally functioning ones. This means it lightens dark spots without bleaching the surrounding skin. In cell studies, azelaic acid significantly reduced both tyrosinase activity and melanin content. Most other common acne treatments, like benzoyl peroxide or clindamycin, do nothing for hyperpigmentation, so azelaic acid pulls double duty.
10% vs. 15% vs. 20% Concentrations
Over-the-counter azelaic acid typically comes in 10% formulations. Prescription versions are available at 15% (usually a gel) and 20% (usually a cream). The assumption that higher is always better doesn’t entirely hold here.
In a 2021 study comparing 10% gel to 20% cream in patients with mild to moderate acne, the 10% gel actually showed a slightly higher success rate (36.5% vs. 30.4% after eight weeks). Researchers attributed this partly to better tolerability. The 20% cream produced an adverse event in one patient, and higher concentrations are more likely to cause burning, stinging, itching, dryness, and redness. For mild acne and uneven skin tone, 10% is a reasonable starting point, particularly if your skin is sensitive.
That said, 15% azelaic acid has shown significant reductions in both inflammatory lesions and acne scarring over six months of use, without notable irritation in study participants. Prescription-strength formulations are generally recommended for moderate to severe inflammatory acne or stubborn hyperpigmentation that isn’t responding to lower concentrations.
Side Effects and What to Expect
Azelaic acid is gentler than many acne treatments, but it’s not side-effect free. The most common reaction is burning, stinging, or tingling, reported by about 29% of users. Itching affects roughly 11%, scaling or dry skin about 8%, and redness or irritation around 4%. These side effects are most noticeable during the first few weeks of treatment and typically settle down as your skin adjusts.
Compared to benzoyl peroxide (which can bleach fabrics and cause significant peeling) or retinoids (which often cause a prolonged “purging” phase with flaking and sun sensitivity), azelaic acid’s side effect profile is relatively mild. It doesn’t increase sun sensitivity the way retinoids do, though sunscreen is still a good idea when treating acne or hyperpigmentation.
Safe During Pregnancy
Azelaic acid stands out as one of the few acne treatments considered safe during pregnancy. The American Academy of Dermatology lists it among the options for pregnant individuals, noting that animal studies have not shown birth defects. This matters because most other effective acne treatments, including retinoids and certain antibiotics, are off-limits during pregnancy. For anyone who is pregnant or planning to become pregnant and dealing with hormonal breakouts, azelaic acid is one of the go-to options.
How to Use It Effectively
Azelaic acid is typically applied twice daily to clean, dry skin. A thin layer over the entire affected area works better than spot-treating individual pimples, since it also prevents new breakouts from forming by keeping pores clear. If you’re new to it, starting with once-daily application for the first week or two can help minimize the initial stinging that many users experience.
It layers well with other products. You can apply moisturizer afterward if dryness is a concern, and it’s compatible with sunscreen applied on top. For combination therapy, azelaic acid can be used alongside benzoyl peroxide or clindamycin (applied at different times of day, or one in the morning and one at night) for enhanced results. If you’re pairing it with a retinoid, applying the retinoid at night and azelaic acid in the morning can reduce the chance of irritation from stacking two active ingredients at once.
Visible improvement in inflammatory acne usually begins within two to four weeks, but comedonal acne and hyperpigmentation take longer. Plan on at least three to four months of consistent use before judging whether it’s working for dark spots or blackheads.