Does Azelaic Acid Help With Acne Scars?

Azelaic acid can help with certain types of post-blemish marks - but the answer depends entirely on what kind of marks you are dealing with. If you are looking at flat red or pink marks left behind after a blemish has healed, azelaic acid is one of the most clinically supported topical ingredients available. If your concern is flat brown or dark marks caused by excess melanin production, azelaic acid is also effective, though results take longer. If, however, you are dealing with indented or raised scarring that involves a change in skin texture, azelaic acid will not address that. These are structurally different problems requiring different solutions.

This blog covers exactly what azelaic acid can and cannot do for post-blemish marks. It explains the three categories of marks that people commonly group under the term “acne scars”, the science behind how azelaic acid works on each, realistic timelines for improvement, and how to use it correctly alongside supporting ingredients. If you want a broader overview of the ingredient itself, visit our azelaic acid guide. For a full breakdown of how to approach post-blemish marks as a category, see our acne scars pillar page.

Our 10% Azelaic Acid Serum for Redness Relief (£16) is clinically proven to minimise redness in 4 days and is the primary product referenced throughout this guide.

Not All Post-Blemish Marks Are the Same

Before understanding what azelaic acid does, it is necessary to understand what type of mark you are treating. This distinction is foundational, and getting it right will determine whether your skincare approach is likely to work or whether you need to explore alternative options.

Post-blemish marks fall into three distinct categories, and conflating them is one of the most common mistakes people make when building a skincare routine for this concern. Each has a different underlying cause, different visual characteristics, and responds to different treatments.

Post-Inflammatory Erythema (PIE) refers to the flat red or pink marks that can persist after a blemish heals. These marks are vascular in origin. During the inflammatory phase of a blemish, capillaries beneath the skin’s surface become damaged and dilated. Once the blemish itself resolves, the vascular damage can persist, leaving a residual redness that sits just below the surface of the skin. PIE is more commonly seen in individuals with lighter skin tones, where vascular changes are more visible against the skin’s background colour. These marks have no depth or texture - they are entirely flat. A useful way to check if a mark is PIE is to press a clean fingertip or a clear glass firmly against it. PIE will typically blanch when pressed, temporarily losing its colour under the pressure, then returning once the pressure is released. This blanching response happens because the redness is caused by blood pooling in dilated vessels, which can be displaced temporarily by external pressure.

Post-Inflammatory Hyperpigmentation (PIH) refers to the flat brown or dark marks that form as a result of excess melanin production triggered by inflammation. When skin experiences injury or prolonged inflammation - as it does during an active blemish - melanocytes, the cells responsible for producing pigment, can become hyperactivated. This results in localised deposits of melanin that appear as darkened patches once the blemish has resolved. PIH is more pronounced in medium to deeper skin tones, where the capacity for melanin production is greater. Unlike PIE, PIH does not blanch when pressed because the discolouration is caused by pigment deposits within the skin’s cells rather than blood in the vessels. PIH marks also tend to be brown, tan, grey, or dark rather than red or pink in colour. In darker skin tones, PIH can be particularly persistent, lasting months to years without treatment.

Atrophic scarring is a fundamentally different category. These are the indented or raised marks - ice pick, boxcar, and rolling scars - that result from structural damage to the skin’s collagen architecture during severe or prolonged inflammation. Unlike PIE and PIH, which are changes in colour at or near the skin’s surface, atrophic scars represent a physical change in skin texture and depth. No topical ingredient, regardless of concentration or combination, can reverse this type of structural collagen loss. Topical skincare works at the surface and near-surface level of the skin; atrophic scarring sits deeper and requires professional intervention such as microneedling, resurfacing lasers, or subcision to achieve meaningful improvement.

Understanding which category your marks fall into is not a minor detail - it is the starting point for any effective approach. Many people who believe they have “scars” are, in fact, dealing with PIE or PIH, both of which respond well to targeted skincare. For a broader look at how to approach different types of post-blemish marks, visit our guide to post-acne dark marks or the acne scars pillar page.

With this distinction established, we can look at precisely where azelaic acid fits - and why it works.

How Azelaic Acid Helps With Red Post-Blemish Marks (PIE)

Of the two flatmark categories, PIE is where azelaic acid demonstrates its most direct and well-evidenced action. The mechanism is anti-inflammatory, and it operates at a cellular level that directly addresses the vascular damage underlying these red marks.

PIE persists because the inflammation that caused the original blemish does not always fully resolve once the visible blemish clears. Residual inflammatory activity keeps capillaries dilated, sustains local vascular damage, and maintains a cycle of redness that can last weeks or months without intervention. Azelaic acid interrupts this cycle through several interconnected mechanisms.

At the cellular level, azelaic acid scavenges reactive oxygen species (ROS) - the unstable molecules produced during inflammation that cause oxidative damage to surrounding tissue. According to a 2024 review of azelaic acid’s mechanisms of action published in Clinical, Cosmetic and Investigational Dermatology (Feng et al.), azelaic acid inhibits the release of ROS from neutrophils, including hydroxyl radicals and superoxide anions, by suppressing NADPH oxidase activity on the neutrophil surface membrane. This is significant because neutrophils are a primary driver of oxidative inflammation in the early and mid stages of skin inflammation. By reducing their output, azelaic acid effectively lowers the inflammatory burden on the skin. Azelaic acid also interferes with the NF-kB/MAPK inflammatory signalling pathways, reducing the production and release of pro-inflammatory cytokines including IL-1beta, IL-6, and TNF-alpha. Additionally, it activates peroxisome proliferator-activated receptor gamma (PPARgamma), which further modulates the inflammatory response.

The clinical evidence for azelaic acid in PIE is compelling. A 2024 randomised, double-blind, placebo-controlled trial published in Dermatology and Therapy (Shucheng et al.) enrolled 72 patients with mild to moderate acne and evaluated the effects of twice-daily application of 15% azelaic acid gel over 12 weeks. Sixty patients completed the trial. The results were statistically significant: at week 12, haemoglobin content in PIE lesions decreased significantly in the azelaic acid group compared to the placebo group (P = 0.033). The post-acne hyperpigmentation index (PAHPI) scores for PIE showed significantly superior improvement in the azelaic acid group at both week 8 (P = 0.046) and week 12 (P less than 0.001). Individual typology angle (ITA) values - a measure of skin brightness - also improved significantly in the azelaic acid group at week 12 (P = 0.037). Total effective rate in the azelaic acid group was 100%, compared to 56.66% in the placebo group. These are meaningful clinical outcomes, not marginal improvements.

“Post-inflammatory marks, particularly the red or pink discolouration left behind after inflammation resolves, are driven by vascular changes that anti-inflammatory ingredients can directly address. Ingredients like azelaic acid, which work on multiple inflammatory pathways simultaneously, are particularly well-suited to this type of concern.” Dr. Adeline Kikam, Board-Certified Dermatologist and founder of Brown Skin Derm

The 10% Azelaic Acid Serum for Redness Relief (£16) has been independently tested and shown to minimise redness in 4 days, with 91% of participants agreeing that skin was instantly soothed. This is consistent with azelaic acid’s anti-inflammatory mechanism - the initial soothing effect reflects its action on ROS and inflammatory mediators, while the longer-term improvement in PIE requires sustained twice-daily use over 8 weeks or more. Visible improvement in PIE typically begins to appear from around weeks 6 to 8, with more substantial fading continuing through weeks 10 to 12 with consistent use.

For those who also experience redness associated with rosacea, it is worth noting that the evidence base for azelaic acid in that context is robust and separately documented. You can read more in our guide to azelaic acid for rosacea-prone skin.

Does Azelaic Acid Help With Dark Post-Blemish Marks (PIH)?

Azelaic acid is also effective for PIH, though the mechanism is different from its action on PIE, and results typically take longer to materialise. Where PIE involves vascular inflammation, PIH involves excess melanin production - and azelaic acid addresses this through a specific, well-characterised biochemical pathway.

The central driver of PIH is tyrosinase activity. Tyrosinase is the enzyme that catalyses the first steps of melanin synthesis within melanocytes. Under normal conditions, tyrosinase converts the amino acid tyrosine into dopa, and dopa into dopaquinone, which is subsequently converted into melanin. When skin experiences inflammation - as occurs during a blemish - pro-inflammatory mediators stimulate melanocytes to upregulate tyrosinase activity, producing excess melanin that gets deposited in the surrounding tissue. This results in the darkened patches characteristic of PIH.

Azelaic acid competitively inhibits tyrosinase, meaning it binds to the enzyme and blocks its ability to process tyrosine into melanin. Crucially, as noted in the Feng et al. (2024) review, azelaic acid selectively targets hyperactive and abnormal melanocytes - those that are overproducing melanin as a result of inflammatory signalling - while leaving normal melanocytes largely unaffected. This selectivity is an important safety characteristic: azelaic acid reduces pathological hyperpigmentation without causing overall skin lightening or affecting areas of normal pigmentation. This makes it particularly appropriate and well-tolerated for use across a range of skin tones, including medium and deeper skin tones where PIH tends to be most pronounced and persistent.

Beyond tyrosinase inhibition, azelaic acid also disrupts mitochondrial metabolism within overactive melanocytes and inhibits DNA synthesis in these cells, further reducing their capacity for excessive pigment production. It also scavenges the reactive oxygen species produced during inflammation that would otherwise further stimulate melanocyte activity.

The clinical evidence mirrors the mechanistic profile. In the same Shucheng et al. (2024) trial, melanin content in PIH lesions was significantly reduced in the azelaic acid group compared to placebo at week 12 (P = 0.006). ITA values - a measure of skin brightness and a proxy for overall pigmentation improvement - also improved significantly in the azelaic acid group (P = 0.022). PAHPI scores for PIH lesions showed significantly superior improvement in the azelaic acid group at both week 8 (P = 0.034) and week 12 (P less than 0.001). Notably, the azelaic acid group also demonstrated significantly better improvement in Dermatology Life Quality Index (DLQI) scores (P = 0.001), reflecting real-world impact beyond the clinical measurements alone.

For PIH, realistic expectations involve a longer treatment window than for PIE. Because PIH involves pigment deposits within skin cells rather than vascular changes, the skin’s natural cell turnover cycle plays a role in how quickly improvement becomes visible. Meaningful fading of PIH typically requires 10 to 12 weeks of consistent twice-daily use. In some cases, particularly where marks have been present for many months, the process may extend further. This is not a limitation specific to azelaic acid - it reflects the biological timescale of melanin clearance.

An important practical note: azelaic acid is classified as pregnancy category B for topical use, meaning it is generally considered safe for use during pregnancy. For individuals who are pregnant and experiencing PIH or active blemish marks, azelaic acid is one of the few evidence-supported options available. Always consult a healthcare professional before introducing any new skincare ingredient during pregnancy.

Those managing PIH alongside post-blemish texture concerns may also benefit from reviewing our related guide on retinol for scarring and post-acne marks, which covers how retinol works differently and when combining approaches may be appropriate.

What Azelaic Acid Cannot Do - The Honest Answer

Ingredient education at The INKEY List means being as transparent about what ingredients cannot do as it does about what they can. Azelaic acid has genuine, clinically supported benefits for post-blemish PIE and PIH - but there are clear limits to what topical skincare can achieve, and those limits need to be stated plainly.

Azelaic acid works at the surface and near-surface level of the skin. Its anti-inflammatory and melanin-inhibiting actions take place in the epidermis and superficial dermis. This makes it highly effective for the flat, pigmentation-based marks described above. It does not, however, penetrate to the depth required to address structural collagen changes.

Atrophic scars - the indented marks left by ice pick, boxcar, or rolling scarring - involve a deficit in the skin’s collagen architecture that sits in the deeper dermal layers. When severe inflammation damages the structural scaffolding of the skin, the resulting loss of collagen cannot be corrected by applying ingredients topically. No serum, no cream, and no combination of skincare actives can rebuild this type of structural deficit. This includes not only azelaic acid but also retinoids, vitamin C, niacinamide, and every other commonly recommended ingredient for post-blemish concerns. For atrophic scarring specifically, professional interventions - microneedling, ablative or fractional laser resurfacing, subcision, dermal fillers, or clinical chemical peels - are the appropriate routes to explore, under the guidance of a qualified dermatologist.

The important and encouraging nuance here is that a significant proportion of people who believe they have “acne scars” are, in fact, dealing with PIE or PIH. These flat marks, while persistent and often distressing in appearance, are not structural damage - they are surface-level changes in vascular activity or pigmentation. That means they are addressable with the right topical approach. Taking the time to identify which category your marks fall into - by the methods described in the first section of this blog - may reveal that your concern is more amenable to skincare than you initially thought.

If you have recently started azelaic acid and are wondering whether the initial phase of use may cause any purging or adjustment period, the topic is addressed in detail in our guide to whether azelaic acid causes purging.

How to Use Azelaic Acid for Post-Blemish Marks

Consistent, correctly timed application is central to azelaic acid’s efficacy. The following guidance covers how to incorporate it effectively into a daily routine when specifically targeting PIE or PIH.

Frequency and timing: For maximum benefit when targeting post-blemish marks, azelaic acid should be applied twice daily - once in the morning and once in the evening. If you are new to the ingredient, start with once-daily evening application for the first one to two weeks to allow your skin to adjust. Some mild tingling, warmth, or temporary redness during the first few weeks of use is normal as the skin acclimatises. Once the skin has adjusted without any persistent irritation, introduce the morning application.

Routine positioning: Azelaic acid should be applied after cleansing and any hydrating serums, and before moisturiser. It is a leave-on treatment, not a step to be rinsed off. Apply a pea-sized amount across the face and neck, spreading evenly rather than concentrating on individual marks.

What not to combine in the same routine: Azelaic acid should not be applied in the same routine as AHAs (such as glycolic or lactic acid), BHAs (such as salicylic acid), retinol, or vitamin C. Combining these in the same routine increases the risk of irritation without meaningfully increasing efficacy. If you use retinol, apply it in your evening routine and use azelaic acid in the morning - or alternate them on separate evenings. For more detail on this pairing specifically, see our guide on using azelaic acid with retinol.

Sample AM routine for PIE and PIH:

Cleanser
Hydrating serum
Moisturiser (e.g. Omega Water Cream (£11))
Dewy Sunscreen SPF 30 (£15)

Sample PM routine for PIE and PIH:

Cleanser
Hydrating serum
10% Azelaic Acid Serum for Redness Relief (£16)
Moisturiser

On SPF: When targeting PIH specifically, SPF is not optional - it is the single step that determines whether your pigment-fading efforts are meaningful or undermined. UV exposure stimulates further melanocyte activity. Without daily SPF application, any progress made by azelaic acid or other brightening ingredients is actively reversed by the ongoing melanin production triggered by UV exposure. Apply a broad-spectrum SPF every morning, regardless of cloud cover or season. The Dewy Sunscreen SPF 30 (£15) is a lightweight, non-greasy option suitable for daily use, even under makeup.

The Best Ingredients to Use Alongside Azelaic Acid for Post-Blemish Marks

Azelaic acid works most effectively when supported by a considered surrounding routine. The following ingredients each address different aspects of PIE and PIH and can be integrated thoughtfully to build a comprehensive approach.

Tranexamic Acid

Tranexamic acid targets PIH via a distinct pathway from azelaic acid’s tyrosinase inhibition. It works by blocking the signalling pathway between keratinocytes - the surface skin cells - and melanocytes, disrupting the inflammatory signal that triggers excess melanin production at an earlier stage in the process. This complementary mechanism means tranexamic acid and azelaic acid can be used in the same routine without redundancy. The Tranexamic Acid Serum (£16) is best used in the morning routine, with azelaic acid reserved for the evening, allowing both ingredients to work in sequence without the risk of layering active ingredients that might compromise skin tolerance. For individuals with stubborn PIH that has not responded sufficiently to azelaic acid alone, adding tranexamic acid is a logical and evidence-supported next step.

Niacinamide 10%

Niacinamide addresses one of the root causes of both PIE and PIH: the inflammatory response itself. By reducing the inflammatory stimulus that drives both vascular damage and melanocyte overactivation, niacinamide effectively reduces the rate at which new post-blemish marks form. This makes it a particularly valuable addition for anyone who is still experiencing active blemishes alongside existing PIE or PIH. It also offers supporting benefits including strengthening the skin barrier, which improves overall skin resilience and helps manage the mild sensitivity that some people experience when first introducing azelaic acid. The 10% Niacinamide Serum (£10) is best applied in the morning routine. For a detailed breakdown of how these two ingredients work together, see our dedicated guide on using azelaic acid and niacinamide together.

15% Vitamin C + EGF Serum

Vitamin C is a potent antioxidant and a secondary tyrosinase inhibitor, making it a relevant supporting ingredient for PIH. It inhibits melanin synthesis through a different biochemical interaction with tyrosinase compared to azelaic acid, and it also provides significant antioxidant protection against UV-induced free radical damage - one of the key drivers of ongoing PIH. The EGF (epidermal growth factor) complex in the 15% Vitamin C + EGF Serum (£15) further supports skin renewal and resilience. Vitamin C is best applied in the morning, as its antioxidant properties are most relevant during daylight hours when UV exposure is a factor. It should not be layered with azelaic acid in the same routine to avoid potential irritation.

Omega Water Cream

An appropriate moisturiser is not a passive step in a post-blemish routine - it plays an active role in maintaining the skin barrier function that allows active ingredients to work effectively without causing excessive sensitivity. The Omega Water Cream (£11) is an oil-free moisturiser formulated with omega fatty acids that support barrier integrity without adding comedogenic occlusion to skin that is prone to blemishes. It is particularly well-suited to combination and blemish-prone skin types and is compatible with both the morning and evening routines described above.

Dewy Sunscreen SPF 30

The Dewy Sunscreen SPF 30 (£15) deserves specific mention not simply as a routine step but as an active contributor to PIH fading. Every unprotected exposure to UV radiation carries the risk of further stimulating the overactive melanocytes responsible for PIH. This means that without daily SPF use, even the most diligently applied pigment-fading routine will be compromised. Broad-spectrum SPF 30 applied each morning - including on overcast days and indoors near windows - is the single most important supporting measure when targeting PIH. The Dewy Sunscreen SPF 30 provides meaningful UV protection in a lightweight, non-greasy formula that works for daily use across all skin types.

Frequently Asked Questions

Is azelaic acid good for acne scars?

Azelaic acid for acne scars is a question that depends on the type of mark in question. For flat red post-blemish marks (PIE) and flat dark post-blemish marks (PIH), azelaic acid is clinically supported and effective. For structural atrophic scarring involving changes in skin texture and depth, azelaic acid will not produce meaningful improvement. The term “acne scars” is frequently applied to all of these, which is why distinguishing between them is so important before building a treatment approach.

How long does azelaic acid take to work on post-blemish marks?

For PIE (red or pink marks), visible improvement typically begins to appear from around 6 to 8 weeks of consistent twice-daily use, with continued fading through weeks 10 to 12. The clinical trial by Shucheng et al. (2024)demonstrated statistically significant PAHPI improvements in PIE from week 8 onward. For PIH (brown or dark marks), the timeline is longer - expect 10 to 12 weeks as a minimum, given that melanin clearance depends on the skin’s natural cell turnover cycle. Consistency is essential throughout.

Can azelaic acid remove acne scars completely?

For PIE and PIH, azelaic acid can produce significant fading and in many cases near-complete resolution with sustained use. However, complete removal cannot be guaranteed for all individuals, as outcomes depend on the age of the marks, skin tone, and consistency of application. For atrophic scarring with visible texture, azelaic acid cannot remove these marks because they involve structural changes beyond the reach of topical ingredients.

Can I use azelaic acid with other scar-fading ingredients?

Yes, with appropriate scheduling. Azelaic acid pairs well with tranexamic acid (use one in AM, one in PM), niacinamide (use in AM alongside or separately from azelaic acid), and vitamin C (use in AM, azelaic acid in PM). Avoid layering azelaic acid in the same routine as AHAs, BHAs, retinol, or vitamin C, as this can increase irritation without improving outcomes. For specific pairing guidance, see our guides on azelaic acid with retinol and azelaic acid with niacinamide.

Is azelaic acid safe for sensitive skin when targeting post-blemish marks?

Generally, yes. Azelaic acid has a well-established safety profile and does not cause photosensitivity, making it usable both morning and evening without increased sun risk. It is one of the few active ingredients considered compatible with pregnancy (category B for topical use). In the Shucheng et al. (2024) clinical trial, adverse reactions - where they occurred - were mild and transient, typically resolving within 7 days as the skin built tolerance. Starting with once-daily evening use and building gradually to twice daily is the recommended approach for those with more reactive skin. The 10% Azelaic Acid Serum for Redness Relief (£16) contains 10% azelaic acid, which is a well-tolerated concentration appropriate for daily use.

The Honest Summary - and What to Do Next

Does azelaic acid help with acne scars? The accurate answer is: yes, for flat post-blemish marks caused by inflammation and pigmentation - and no, for structural textural scarring. Within its scope of action, azelaic acid is one of the most clinically substantiated topical options available for both PIE and PIH, supported by two distinct mechanisms - anti-inflammatory vascular action and selective tyrosinase inhibition - and validated in randomised controlled clinical trials.

The key conditions for success are clarity on what you are treating, consistency of application over 8 to 12 weeks, and a supporting routine that protects the skin’s barrier and shields it from UV exposure. Azelaic acid does not produce overnight results, but it does produce measurable, clinically demonstrated results with sustained use. That is a meaningful distinction from many ingredients in the skincare space.

If you are dealing with PIE, PIH, or both, the 10% Azelaic Acid Serum for Redness Relief (£16) is the appropriate starting point - formulated at a concentration that is effective and well-tolerated for twice-daily use. Pair it with daily SPF, support the barrier with a suitable moisturiser, and consider adding tranexamic acid or niacinamide to target pigmentation from multiple pathways.

Shop our 10% Azelaic Acid Serum for Redness Relief (£16)

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