Benzoyl Peroxide
what it does
A topical antibacterial that kills acne-causing P. acnes bacteria through oxidative activity while providing mild exfoliation. Available OTC in concentrations from 2.5–10%.
Straight-up nukes acne bacteria with oxygen — brutal, effective, no notes. 2.5% works as well as 10% with way less irritation, so don't be a hero. Will bleach your towels. You have been warned.
targets these concerns
don't combine with
Benzoyl peroxide oxidises tretinoin on contact, rendering it inactive. Never layer them in the same session.
💡 AM: benzoyl peroxide. PM: tretinoin only, after it fully absorbs.
Benzoyl peroxide degrades retinol through oxidation, completely eliminating its anti-ageing efficacy.
💡 Use in strictly separate AM/PM sessions — never in the same layer.
Benzoyl peroxide can oxidise ascorbic acid, reducing vitamin C's brightening and antioxidant effect.
💡 AM: vitamin C. PM or separate session: benzoyl peroxide.