Benzoyl Peroxide
A widely used acne medicine that works on pore-clogging bacteria; it can be drying, so start low and use it under guidance.
benzoyl peroxide, BPO, dibenzoyl peroxide
Blemish-prone skin
What it does
A long-standing mainstay for blemish-prone skin, benzoyl peroxide remains one of the most widely used acne treatments. It can be drying, so lower strengths (2.5–5%), spot treatment or short-contact washes are the usual way to start. It is an acne medicine rather than a cosmetic ingredient, sold in washes, gels and creams.
How it works
When applied to the skin, benzoyl peroxide releases oxygen into the pore, which the acne-causing bacteria living there cannot survive, and it helps loosen the dead cells that block pores. Because it works differently from antibiotics, bacteria don’t become resistant to it, which is why it is often paired with them in prescription treatments.
MG says
While benzoyl peroxide has its place in acne care, it can also be incredibly harsh, causing dryness and sensitivity, so start with a low strength as a spot treatment or a short-contact wash. Don’t layer it with exfoliating acids, which only adds to the irritation, and ideally only use benzoyl peroxide under the direction of a clinician. It bleaches fabric, so use white towels and pillowcases.
Cautions
It can cause dryness, peeling, redness and, rarely, an allergic reaction, so start low and patch test. It bleaches fabrics and hair. Apply it at a different time from vitamin C (L-ascorbic acid) and tretinoin, as it can make them less effective. If you’re pregnant, trying to conceive or breastfeeding, check with your doctor, midwife or pharmacist before using it: low-strength, wash-off spot treatments are generally considered acceptable in pregnancy, but extensive use needs medical advice, and when breastfeeding, keep it off the chest or wash it off before feeding.
Regional notes
Australia: Benzoyl peroxide products with acne claims are therapeutic goods; strengths above 5% are pharmacy medicines, and above 10% prescription-only.
United States: Benzoyl peroxide at 2.5–10% is an over-the-counter acne drug. In 2025 the FDA found most products it tested had undetectable or very low benzene; store as directed and don’t use after expiry.
United Kingdom: In the UK and EU, benzoyl peroxide isn’t permitted in skin cosmetics; skin products containing it are medicines, sold in pharmacies or on prescription.
