Benzoyl peroxide
Other dermatological medicines
Other dermatological medicines
An oxidising gel or wash that kills acne bacteria and loosens blackheads. Added to antibiotics to limit resistance; it can bleach hair and fabric.
Quick facts
- Group
- Other dermatological medicines
- Target
- Cutibacterium acnes and the keratin plug of the follicle (oxidation)
- Used for
- Mild to moderate acne
- Key effects
- Dryness and peeling of the skin · Warmth
- Monitor
- Irritation · Response after several weeks
- ATC
- D10AE01
No doses: the clinician sets them by the current guideline.
Mechanism of action
Benzoyl peroxide is an organic peroxide that acts by oxidation. Applied to the skin it kills Cutibacterium acnes, the anaerobe that multiplies in the plugged, sebum-rich follicle, and it is mildly comedolytic. Antibiotics used alone for acne select resistant bacteria; adding benzoyl peroxide improves efficacy and reduces that resistance. Its oxidising action also bleaches hair, clothing and towels and inactivates topical tretinoin.
- Benzoyl peroxide oxidises bacteria in the plugged follicle
- C. acnes is killed
- Mild comedolytic effect loosens blackheads
- Fewer papules, pustules and comedones
Indications
- Mild to moderate acne, alone or with a topical retinoid or antibiotic Acne vulgaris →
- Added to systemic antibiotics for acne to reduce bacterial resistance Acne vulgaris →
Adverse effects
Common
- Dryness and peeling of the skin
- Warmth, tingling or slight stinging
- Redness and irritation, more with stronger products
- Bleaching of hair, clothing and bed linen
- More sensitivity to sunlight
Contraindications
- Hypersensitivity to benzoyl peroxide or any component
Key interactions
- Topical tretinoin
- Benzoyl peroxide oxidises and inactivates tretinoin, so they are not applied at the same time; adapalene is stable with it.
- Other drying or irritating acne treatments
- Additive dryness and peeling; combined only when advised.
- Topical dapsone
- Temporary yellow to orange-brown discolouration of skin and hair.
What is monitored
- Irritation, dryness and peeling during the first weeks
- Response after several weeks of regular use; worsening acne needs review
- Signs of allergy
Administration and safety
- Applied to clean, dry skin; a small test area first shows how the skin reacts.
- Kept away from the eyes, mouth, nose and mucous membranes.
- It bleaches: contact with hair, coloured clothing, towels and bedding is avoided.
Pregnancy and breastfeeding
It can usually be used during pregnancy, after checking with the prescriber.
Nursing care
- Teach that dryness, warmth and stinging are common, and that burning, blistering or swelling is reported at once.
- Teach sun protection while it is used.
- Explain that results take weeks, so it is not stopped early.
- Warn that it bleaches pillowcases, towels and coloured clothing.
Pharmacokinetics
- Absorption
- Acts on the skin surface and in the follicle.
- Onset and duration
- Improvement after several weeks of regular use.
Test yourself
Think of the answer, then tap the question to see it.
What is the main reason to add benzoyl peroxide when an antibiotic is used for acne?
To improve efficacy and reduce the emergence of antibiotic-resistant bacteria.
Why should tretinoin and benzoyl peroxide not be applied at the same time?
Benzoyl peroxide oxidises and inactivates tretinoin (adapalene is stable with it).
What practical warning is given with benzoyl peroxide?
It bleaches hair, clothing, towels and bedding.
Connections
← Back to the class: Other dermatological medicines
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Benzoyl Peroxide Topical: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Benzoyl peroxide: a medicine to treat acne (NHS, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.