Benzoyl Peroxide

Potent antibacterial and keratolytic for moderate acne.

Also known as: Benzoyl peroxide, BPO; same name.

What it is

Benzoyl peroxide is an organic peroxide that releases free radicals when applied to skin. It's a non-antibiotic antimicrobial agent available in concentrations typically ranging from 2.5% to 10%.

What it does

It kills *Cutibacterium acnes* (formerly *Propionibacterium acnes*) by oxidative damage, reduces sebum production, and promotes mild exfoliation of the follicular epithelium. Unlike antibiotics, bacteria cannot develop resistance to benzoyl peroxide because of its oxidative mechanism. It also has mild anti-inflammatory effects.

The evidence

Strong clinical evidence supports efficacy for mild-to-moderate inflammatory acne; it is a first-line OTC and Rx agent. Moderate evidence supports its use in combination with topical antibiotics or retinoids to prevent antibiotic resistance and improve outcomes.

Best for

Oily, acne-prone skin with inflammatory lesions (papules, pustules); effective for both facial and body acne.

Pairs well with

Topical antibiotics (clindamycin, erythromycin), retinoids (adapalene, tretinoin), salicylic acid, and azelaic acid. Combination with antibiotics is particularly effective and reduces resistance risk.

Use cautiously with

Avoid concurrent use with vitamin C, retinol, and AHAs/BHAs in the same formula (oxidative degradation and irritation risk). Use caution with other drying or irritating actives; space application if combining.

Cautions

Causes dryness, irritation, and photosensitivity; use SPF 30+ daily. May bleach fabrics and hair. Rare allergic contact dermatitis. Generally safe in pregnancy but consult prescriber; avoid high concentrations. Start low (2.5%) and titrate to tolerance.