Benzoyl Peroxide

Tolerability and safety

Working concentrations

2.5–10% (2.5% works as well as 10% with less irritation)

Irritation potential

High

Allergen risk

Moderate

Pregnancy

Caution

Suitable for

Oily, Combination

Use with caution

Sensitive, Dry

For sensitive skin

Dries the skin and may cause peeling. Contact allergy develops in 1–2% of patients. Bleaches fabrics and hair.

About this ingredient

Benzoyl Peroxide (BPO) is an organic peroxide compound, one of the oldest and most effective OTC and prescription anti-acne agents. On the market since the 1930s. Mechanism. In skin it decomposes and releases reactive oxygen radicals. The radicals damage membranes and proteins of Cutibacterium acnes – the main bacterial player in inflammatory acne. Unlike antibiotics, BPO acts non-specifically: no antibiotic resistance. It also mildly exfoliates the stratum corneum and helps follicular openings. Where applied. Lotions, gels, creams for face and body, cleansers (2.5–10%). In Spain prescription Akneroxid 5–10%, Peroxiben 5–10%; OTC – Effaclar Duo+ (La Roche-Posay), Cleanance Comedomed (Avène). Often combined with topical retinoids (adapalene, tretinoin); fixed combinations in Spain include Epiduo (BPO + adapalene) and Treclinac (BPO + clindamycin). Evidence base. Cochrane review Yang 2020 (39 RCTs, n=4,400) showed BPO 2.5–10% significantly reduces inflammatory and non-inflammatory acne lesions over 12 weeks. 2.5% and 5% work almost as well as 10% with less irritation (Mills 1986). BPO + adapalene or BPO + clindamycin combinations outperform monotherapy (Thiboutot 2007). AAD 2024 recommends BPO as first-line in mild to moderate acne. Safety. Irritation, dryness, scaling, erythema in the first 2–4 weeks in 30–60% of patients – usually resolves with adaptation. Lower frequency and pairing with a moisturiser improve tolerance. Does not photosensitise directly, but irritated skin is more vulnerable – daily SPF 30+. BPO permanently bleaches fabrics (towels, pillowcases, clothing). Contact allergy is rare, 1–3%. Pregnancy and lactation – use with caution. FDA category C (no adequate human studies). Topical systemic absorption is low (<5%), but as a precaution AEMPS and SEGO 2023 recommend avoiding without necessity. If needed – locally on limited areas at 2.5–5%. For gestational acne the first-line agents are azelaic acid and EU-approved topical clindamycin. Particularly suitable for. Mild and moderate acne, especially inflammatory lesions; antibiotic-resistance prevention (use instead of or alongside antibiotics). Not for patients with active eczema, perioral dermatitis, or sensitive skin in flare.

Frequently asked questions