What it does
Benzoyl peroxide kills the bacteria involved in inflammatory acne and, unlike antibiotics, resistance does not develop against it. For red, painful spots it outperforms almost everything else available without a prescription.
It is drying, it can be irritating, and it genuinely bleaches fabric — pillowcases, towels and dark shirts. Use white towels and bedding while you are on it, which sounds like a joke and is not.
Higher strength is not better. 2.5% has been shown to work about as well as 10% with far less irritation. Short-contact therapy — applying it as a wash and rinsing after a couple of minutes — is a good compromise for drier skin.
In a routine
Layers well with
- Ceramides
- Niacinamide
- Moisturiser
Patch-test protocol
Patch a thin layer on intact skin for two to three evenings. Expect dryness; stop if you get intense burn, swelling, or a rash. Keep the test area away from dyed fabric — bleaching is real.
Short-contact testing (apply, wait a few minutes, rinse) is a valid way to gauge tolerance before overnight leave-on use.
Test on the jaw or behind the ear and keep that shirt white — bleaching during a patch week is still bleaching.
Cosmetic caution for home use — not a diagnosis or medical advice. Stop and seek a professional if you get swelling, blistering, or symptoms that worry you.
Reintroducing after a break
After a break for dryness, restart at 2.5% every other night or as a short-contact wash. Moisturise immediately after. Do not resume 10% leave-on because spots returned during a holiday.
If you paused while using antibiotics or another acne plan from a clinician, ask them before combining again — stacking without guidance is how barriers collapse.
After a dry, peeling month off BPO, return with short-contact 2.5% before overnight leave-on. Moisturise before and after for the first week.
Serum, cream, or encapsulated?
Washes and short-contact gels suit drier skin; leave-on 2.5–5% gels suit oilier inflammatory acne. Creams can be gentler cosmetically. Micronised or encapsulated BPO is designed to cut irritation while keeping antibacterial activity — a fair upgrade if classic BPO shredded your moisture barrier.
Spot treatments tempt overuse; a thin film on affected zones beats paste-thick layers. Never mix in the same palm with retinol or vitamin C serums.
Washes suit maintenance; leave-on gels suit active inflammatory spots. Micronised leave-ons are the format upgrade when classic BPO was effective but intolerable.
