Ingredient glossary
Benzoyl Peroxide
On your shelf ✓What Benzoyl Peroxide does for your skin, who it suits, and what to watch for.
INCI: Benzoyl Peroxide · Also: BPO
In short: Benzoyl Peroxide delivers anti acne and antibacterial, suits combination and oily skin best, and the evidence behind it is strong. One thing to know: clear it with your doctor if pregnant; can irritate, ease in slowly.
- What it does
- Anti acne, antibacterial
- Best for
- Combination, Oily skin
- Watch out
- Clear it with your doctor if pregnant; can irritate, ease in slowly
- Evidence
- Strong
- How long
- 2–4 weeks
The molecule
The Glow take
One of the ingredients I trust most.
When your goal is calming breakouts and congestion, Benzoyl Peroxide delivers, and the research properly backs it up. It can sting a fresh or sensitive barrier, so start a couple of nights a week and always patch test first.
— Maya
What it does
- anti acne
- antibacterial
- comedolytic
strong evidenceMultiple large randomized trials with two point five to ten percent gels show around sixty to seventy percent reductions in inflammatory and non inflammatory lesion counts versus vehicle with frequent but usually mild irritation.
On a label: usually effective at 2.5-10%.
Who it's for, and who should skip it
Tends to suit
- oily
- acne prone
- combo
Approach with care
- very sensitive
- compromised barrier
- pregnancy
- Clogs poresModerate
- Irritation riskHigh
How it fits each skin type
- DryNeutral
- CombinationSuits
- OilySuits
- SensitiveTake care
Often chosen for acne prone. Take extra care if any of these apply to you: compromised barrier, pregnancy.
Where it fits in your routine
Increases sun sensitivity while you are using it, so sunscreen matters more than usual.
US OTC benzoyl peroxide acne products carry a sun warning in their Drug Facts directing users to avoid unnecessary sun exposure and use a sunscreen; that is a labelling direction rather than a demonstrated drop in minimal erythema dose, but it is the regulator-backed position.
US OTC acne drug product labelling for benzoyl peroxide: the sun-exposure warning ("avoid unnecessary sun exposure and use a sunscreen")
Reckon on two to four weeks. No trial pins the exact point down; that is the standard clinical expectation.
What was measured, and in whom
Measured on: Inflammatory lesion count (papules and pustules), investigator-counted.
The cited vehicle-controlled work is real - three double-blind studies in 153 patients in which 2.5% gel beat its own vehicle on inflammatory lesion counts and matched 5% and 10% with less desquamation and burning - but the only timepoint that paper attaches to a result is two weeks, and it attaches it to Cutibacterium acnes counts and surface free fatty acids, not to lesions. No vehicle-controlled trial of benzoyl peroxide alone that I could locate reports the visit at which inflammatory counts first separated from vehicle; the twelve trials pooled in the 2015 systematic review are 12-week designs read at their endpoints, at 44.3% total-lesion reduction against 27.8% on vehicle. So 2-4 weeks is the settled clinical expectation, underwritten by a documented two-week kill of the organism that drives the lesions, rather than a measured first-significant visit. Irritation is front-loaded into those same two weeks, so the side effect usually arrives before the result, and 2.5% delivers the same lesion reduction as 10% with less of it.
PMID:2948929 (Mills OH Jr, Kligman AM, Pochi P, Comite H. Comparing 2.5%, 5%, and 10% benzoyl peroxide on inflammatory acne vulgaris. Int J Dermatol 1986;25(10):664-7) - vehicle-controlled, 153 patients, two-week figure reported for C. acnes and free fatty acids. PMID:26048131 (Lamel SA, Sivamani RK, Rahvar M, Maibach HI. Arch Dermatol Res 2015;307(9):757-66) for the pooled 12-week vehicle-controlled endpoints. No trial reporting an earliest-significant lesion visit located.
Plays well with
- adapalene
- clindamycin
- niacinamide
Benzoyl Peroxide, answered
Is Benzoyl Peroxide safe during pregnancy?
Clear it with your doctor first. Benzoyl Peroxide is flagged as use-with-caution during pregnancy and breastfeeding, so check with your doctor or midwife before adding it.
Who should avoid Benzoyl Peroxide?
Approach Benzoyl Peroxide with care if any of these apply to you: very sensitive, compromised barrier, and pregnancy. Its irritation risk is high, so introduce it slowly and patch test first. It carries a moderate risk of clogging pores, so acne-prone skin should go carefully.
What concentration of Benzoyl Peroxide actually works?
Benzoyl Peroxide tends to do its job in the 2.5 to 10% range. Much lower and it is likely underdosed.
During pregnancy
Treat Benzoyl Peroxide as a maybe rather than a yes for now. It is flagged as one to use with caution while pregnant or breastfeeding, so it is worth clearing before you carry on.
When in doubt, check with your doctor or midwife. They outrank any website, including this one.When it is worth booking →
Commonly confused with
- Salicylic acid (BHA)Both fight breakouts, differently. Benzoyl peroxide kills acne bacteria; salicylic acid unclogs the pore.
Compare Benzoyl Peroxide with
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