Is benzoyl peroxide an antibiotic?

How can it kill bacteria without being an antibiotic?

Benzoyl peroxide releases reactive oxygen that damages bacterial proteins. It acts against Cutibacterium acnes, a bacterium involved in acne, on the skin and inside hair follicles. Antibacterial and antibiotic are not interchangeable labels, however much the similar spelling tries to help. Benzoyl peroxide also helps loosen blocked pores and reduce inflammation, so its role is broader than reducing bacteria alone.34

Does benzoyl peroxide cause antibiotic resistance?

Benzoyl peroxide does not cause bacterial resistance. Used with an acne antibiotic, it can help reduce the growth of bacteria resistant to that antibiotic. That is one reason the two treatments are used together rather than treated as competing options. Acne antibiotics include clindamycin and erythromycin. A product containing either alongside benzoyl peroxide contains an antibiotic; benzoyl peroxide alone does not.345

Not every combination contains an antibiotic: adapalene is a retinoid, a medicine related to vitamin A. The active ingredient list tells you which combination you have, while the product name gets to concentrate on sounding like a product name. If you already use prescribed acne medicine, ask your pharmacist or prescriber before adding benzoyl peroxide, because combining treatments can increase irritation.245

How should you use it for acne?

Benzoyl peroxide is especially useful for mild pimples. Common strengths are 2.5%, 5% and 10%; start with 2.5% where available to reduce dryness and irritation. Creams, lotions, gels and washes exist, but their directions are not interchangeable. Check whether your product stays on or rinses off, and whether it is intended for your face or body.146

1. 1For a gel that stays on, wash your hands, gently clean and dry the skin, then apply a thin layer across the acne affected area rather than only individual spots. Wash your hands afterwards.
2. 2For an NHS described gel wash, wet the affected area, wash with a small amount for 1 to 2 minutes, rinse thoroughly and pat dry. Wash your hands afterwards. Follow your own product's directions if they differ.
3. 3For a treatment that stays on, begin every second night and build towards once or twice daily as tolerated and directed. Add a light, non oily moisturizer if the treated skin becomes scaly.

How long does it take to work?

Benzoyl peroxide usually starts working within 4 weeks. With acne treatment generally, fewer breakouts can appear in 4 to 8 weeks, while clearing can take about 16 weeks. Use treatment consistently rather than adding another acne product immediately. Seek advice if acne worsens or has not improved after 12 weeks. Large, deep, painful pimples or acne that leaves scars need a dermatologist rather than relying on shop bought treatment.16

Who should be careful, and when should you stop?

Most adults and children aged 12 or older can use benzoyl peroxide. Avoid infected or broken skin and keep it away from eyes and mouth. Use sunscreen, avoid sunbeds and protect fabrics and hair from bleaching. During pregnancy, check with your doctor; while breastfeeding, check first and avoid applying it to the breasts.2

Dryness, peeling and mild irritation can improve with less frequent use. Stop if irritation is marked or severe, and get advice for persistent or troublesome symptoms. Do not use it if you have previously had an allergic reaction to benzoyl peroxide. Throat or tongue swelling or difficulty breathing requires emergency medical help.123