Does Benzoyl Peroxide Help Acne Scars? What the Evidence Actually Shows
Updated: Aug 28
Benzoyl peroxide is one of the most widely used over-the-counter and prescription ingredients for acne, and it is often marketed alongside claims about "acne scars." But treating active breakouts and treating the marks or indentations left behind are not the same thing, and the research on each is quite different. This article looks at what clinical studies actually show about benzoyl peroxide's role in acne, its effect on scar formation, and its limitations when it comes to scars and marks that are already present.
Quick Answer
Benzoyl peroxide is approved and studied as a treatment for active acne (comedones and inflammatory lesions), not as a treatment for existing scars.
Some clinical trial evidence suggests that a combination of benzoyl peroxide with a topical retinoid (adapalene), used to treat active acne, may help reduce the formation of new atrophic (indented) scars while acne is being treated.
Current evidence does not support benzoyl peroxide, used on its own, as a way to improve the depth, texture, or pigmentation of scars that are already present.
For post-inflammatory hyperpigmentation (PIH), post-inflammatory erythema (PIE), or established atrophic and keloid scars, other approaches — some topical, some professional — are generally considered more relevant.
What Benzoyl Peroxide Is and How It Works
Benzoyl peroxide (BPO) is a topical antimicrobial and mild keratolytic agent that has been used in acne treatment for decades. It works mainly by releasing oxygen within the pilosebaceous follicle, which reduces the population of Cutibacterium acnes (formerly Propionibacterium acnes), a bacterium implicated in inflammatory acne. It also has a mild comedolytic effect, helping to loosen the buildup of dead skin cells and sebum that contributes to blocked pores, and it has some direct anti-inflammatory activity within the follicle.
Because its mechanism targets the bacterial and inflammatory drivers of acne rather than pigment cells or collagen, benzoyl peroxide's primary, well-established role is in treating active acne lesions rather than working directly on the structural or pigmentary changes left behind after a lesion has healed.
BPO is available in a range of formulations and concentrations, typically between 2.5% and 10%, as a stand-alone product or combined with other actives such as adapalene, clindamycin, or salicylic acid.
Does Benzoyl Peroxide Help Acne Scars? Reviewing the Evidence
To answer this question properly, it helps to separate three distinct issues: (1) how well benzoyl peroxide treats active acne, (2) whether it affects the formation of new scars while acne is being treated, and (3) whether it can improve scars or marks that already exist.
Effect on Active Acne Lesions
Benzoyl peroxide's effect on active acne has been studied extensively, though the overall quality of evidence is mixed. A systematic review of trials involving over 2,000 participants found that while benzoyl peroxide showed some reduction in acne lesion counts, the available studies were often of variable methodological quality, and the authors concluded that high-quality evidence for its effectiveness on facial acne vulgaris remained limited at the time. A later Cochrane systematic review similarly assessed benzoyl peroxide's effects and safety, used alone and in combination with other topical agents, and found it to be a reasonable option with a generally acceptable safety profile, while noting that direct comparisons between formulations were often inconsistent across trials.
In practice, benzoyl peroxide is more commonly used as one component of a combination regimen — for example, paired with a topical retinoid or a topical antibiotic — rather than as a stand-alone therapy, partly because combination approaches are supported by a larger and more consistent body of trial evidence.
Effect on Scar Formation (Prevention, Not Reversal)
This is the area where benzoyl peroxide has the most direct connection to "acne scars," but the finding is about preventing new scars from forming, not improving scars that already exist.
A split-face, investigator-blinded randomised controlled trial examined a fixed-dose combination of adapalene and benzoyl peroxide against a vehicle (inactive base) gel in adults with moderate facial acne who already had multiple atrophic scars. Over six months, the side of the face treated with the adapalene/benzoyl peroxide combination showed a stable atrophic scar count, while the vehicle-treated side showed an increase of roughly 25% in scar count. A separate, larger trial using a similar combination over 24 weeks reported a reduction in existing atrophic scar count on the actively treated side, alongside a reduction in acne lesions, with improvements reported to be maintained through a 48-week extension.
These findings are notable because very few topical acne treatments have been studied specifically for their effect on scar formation. However, some important caveats apply:
The studies used a fixed combination of a retinoid (adapalene) and benzoyl peroxide — the observed effect cannot be attributed to benzoyl peroxide alone.
The benefit relates to controlling active acne early, thereby reducing the ongoing tissue damage that leads to new scars — it is a preventive mechanism, not a scar-erasing one.
These are prescription-strength, retinoid-containing combination products; over-the-counter benzoyl peroxide products are formulated differently and have not been studied in the same way for this specific outcome.
Effect on Existing Atrophic, Boxcar, or Ice-Pick Scars
For scars that already involve loss of collagen and tissue depth, current evidence does not indicate that benzoyl peroxide — alone or in combination — can meaningfully fill in or reduce the depth of established depressions. Its mechanism does not involve stimulating the type of deep collagen remodelling that these scars require. Structural scars of this type are generally considered to need procedures that work at a deeper skin level, discussed further below.
Effect on Post-Inflammatory Hyperpigmentation (PIH) and Erythema (PIE)
Direct clinical evidence for benzoyl peroxide improving PIH or PIE specifically is limited. Because benzoyl peroxide can shorten the duration and severity of inflammatory acne lesions, there is a plausible, indirect argument that treating breakouts more effectively and earlier may reduce the intensity of the inflammation that leads to PIH and PIE in the first place. This is a reasonable mechanistic inference rather than a well-established, directly studied outcome, so it should be treated as a secondary benefit rather than a primary indication.
For readers primarily dealing with post-inflammatory hyperpigmentation rather than active acne or scar prevention, our separate article on niacinamide and acne scars covers that ingredient's evidence in more depth.
Using Benzoyl Peroxide Safely
For those using benzoyl peroxide as part of an acne routine, a few practical points are commonly recommended:
Start with a lower concentration (around 2.5%) to assess tolerance before considering higher strengths, as higher concentrations do not necessarily produce better results but can increase irritation.
Apply to clean, dry skin, and introduce it gradually (for example, every other day) if you have sensitive or dry skin.
Use a broad-spectrum sunscreen daily, as benzoyl peroxide can increase skin sensitivity to UV exposure.
Be aware that benzoyl peroxide can bleach fabric, towels, and hair — use white or old linens where possible.
If combining with other active ingredients such as retinoids or exfoliating acids, consider alternating application times or days to reduce the risk of irritation, and introduce new actives one at a time.
Potential Side Effects
Benzoyl peroxide is generally well tolerated, but dryness, peeling, mild stinging, and redness are common, particularly when starting treatment or using higher concentrations. These effects often settle as the skin adjusts. Less commonly, some individuals develop contact dermatitis or a more pronounced allergic reaction, which would warrant stopping use and seeking medical advice. Because responses vary from person to person, anyone with sensitive skin, an existing skin condition, or who is using other prescription topical treatments should discuss benzoyl peroxide use with a doctor before starting.
When Benzoyl Peroxide Isn't Enough: Options for Established Acne Scars
Because benzoyl peroxide's role is centred on active acne and scar prevention, individuals dealing with scars that are already present — particularly structural, atrophic scarring — often look into professional options. The suitable approach generally depends on the type of scarring involved, which is why an in-person assessment is typically the starting point.
Scar or mark type | Characteristics | Approaches often considered |
Atrophic (ice-pick, boxcar, rolling) | Indented, structural collagen loss | Fractional laser resurfacing, radiofrequency microneedling, subcision, dermal fillers |
Post-inflammatory erythema (PIE) | Red/pink flat marks from vascular changes | Pulsed dye laser (such as Vbeam), sun protection, time |
Post-inflammatory hyperpigmentation (PIH) | Brown/tan flat marks from excess melanin | Topical agents (e.g. niacinamide), sun protection, in some cases laser or peel-based approaches |
Hypertrophic/keloid | Raised, excess collagen | Silicone-based products, pressure therapy, corticosteroid injections, and other procedures under specialist guidance |
Which of these is relevant depends on the scar type present, which is why an in-person assessment for acne scar treatment — reviewing scar type, skin type, and medical history — is generally the starting point rather than any single ingredient or device. Any procedure should only be carried out by a licensed medical practitioner, using devices and products registered for use in Singapore.
When to See a Doctor
It is worth speaking to a doctor if you are unsure which type of post-acne change you are dealing with, if scarring is moderate to severe or continuing to change, if you experience persistent irritation from topical products, or if you are considering combining benzoyl peroxide with prescription treatments. A doctor can assess your scar pattern and skin type and discuss which combination of topical and, where relevant, professional approaches may be appropriate for you.
Conclusion
Benzoyl peroxide has a well-established place in treating active acne, and there is reasonable trial evidence that using it in combination with a topical retinoid, as part of ongoing acne treatment, may help limit the formation of new atrophic scars. However, current research does not support benzoyl peroxide — used alone or in combination — as a treatment for scars, hyperpigmentation, or redness that is already present. For those changes, other topical ingredients and professional procedures are generally more relevant, and the right combination depends on an individual assessment of the type and severity of post-acne changes present.
Note: This article is for educational purposes only and does not constitute medical advice. Individual treatment plans should be developed in consultation with qualified healthcare professionals. Treatment outcomes vary from person to person, and no guarantee of results is intended or implied. All professional treatments mentioned should be performed by licensed medical practitioners in Singapore, using HSA-approved or otherwise MOH-approved products, devices, and techniques, as applicable.
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