Benzoyl peroxide is one of the oldest acne treatments still in use, and one of the best. It kills the bacteria involved in inflamed spots, it loosens blocked pores a little, and bacteria don't become resistant to it the way they do to antibiotics. Acne guidelines in Europe and the US still list it as a first-line treatment.
It also has a reputation for dry, flaky skin and bleached pillowcases. Both are avoidable, or at least manageable, if you use a sensible strength and introduce it slowly.
I'm not a doctor. If your acne is painful, scarring, or not improving after three months of over-the-counter treatment, see a GP. Prescription options work much better for moderate to severe acne.
What benzoyl peroxide does
Inflamed spots (the red, raised ones and the ones with pus) involve a bacterium called Cutibacterium acnes. Benzoyl peroxide releases oxygen inside the pore, and C. acnes doesn't survive well in oxygen. It also has a mild peeling effect that helps clear the dead skin that blocks pores.
That makes it best for:
- Red, inflamed spots and pustules. This is where it works best.
- Acne on the chest and back, especially as a wash, because it's easy to apply over a large area.
- Using alongside antibiotics. Doctors pair it with topical or oral antibiotics specifically because it stops resistant bacteria taking over.
It's less effective on its own for blackheads and closed comedones (the small skin-coloured bumps). Those respond better to salicylic acid or a retinoid. Many people end up using benzoyl peroxide for inflamed spots and something else for clogged pores.
Which strength: 2.5%, 5% or 10%?
Higher isn't better. In a set of double-blind trials published in 1986, 2.5% benzoyl peroxide reduced inflamed spots as much as 5% and 10%. The 2.5% gel caused less redness, peeling and burning than the 10%, and about the same as the 5%.
So for a leave-on gel or cream, start at 2.5% or 5%. There is rarely a reason to use 10% on your face.
Washes are different. You rinse them off, so contact time is short, and a higher strength makes more sense. A lab study of C. acnes found that 5% and 10% benzoyl peroxide killed the bacteria within about 30 seconds of contact, while 2.5% needed around 15 minutes. That was in a dish, not on skin, but it supports the common advice: if you use a wash, use 5% or more and leave the lather on for a minute or two before rinsing.
Where to buy it in the UK
In the UK, most benzoyl peroxide products are pharmacy medicines. You buy them from the pharmacy counter rather than the beauty aisle, and the pharmacist may ask a couple of questions. Acnecide and PanOxyl are the familiar brands, sold as gels and washes. Strengths and formats change, so ask what's in stock.
Your GP can prescribe combination gels that pair benzoyl peroxide with adapalene (a retinoid) or clindamycin (an antibiotic). These are more effective than benzoyl peroxide alone for moderate acne.
How to start without wrecking your skin
The usual mistake is putting a thick layer on your whole face every night from day one. Here's a gentler start:
- Start every other night, or every third night if your skin is sensitive.
- Use a thin layer over the whole area where you break out, not just on individual spots. It works partly by preventing new ones.
- Apply it to dry skin after cleansing. Wait a few minutes after washing.
- Moisturise. Either before (as a buffer, if you're getting irritated) or after. A plain, fragrance-free moisturiser is fine.
- Build up slowly to once a day over two to three weeks, if your skin is coping.
- Wear SPF in the day. Benzoyl peroxide isn't a strong photosensitiser, but irritated skin burns more easily.
Some dryness and mild peeling in the first couple of weeks is normal. Burning, swelling or itching that gets worse rather than better is not. Stop, and check with a pharmacist. A small number of people have a true allergy to it.
Short contact therapy is another option if leave-on gels are too much. Apply the gel or wash, leave it for a few minutes, then rinse it off. You get some of the effect with less irritation.
How long it takes
Expect to see some improvement after about four to six weeks, and the full effect after two to three months. If nothing has changed after three months of consistent use, that's the point to see a GP rather than switching to another over-the-counter product.
Benzoyl peroxide doesn't usually cause "purging" the way retinoids can. If your skin gets noticeably worse, irritation is the more likely cause.
What not to mix it with
Tretinoin. Benzoyl peroxide can break down some tretinoin formulations. Use them at different times of day (benzoyl peroxide in the morning, tretinoin at night) unless your prescriber says otherwise. Adapalene is stable alongside it, which is why the two are combined in one prescription gel. More in the tretinoin guide.
Vitamin C. Benzoyl peroxide is an oxidiser and vitamin C is an antioxidant. Using them in the same step wastes the vitamin C. Use them at different times.
Other strong exfoliants at the same time. Benzoyl peroxide plus a high-strength AHA plus retinol in one routine is a fast way to damage your skin barrier. Pick one or two actives, not five. Ingredients you shouldn't mix covers the common clashes.
Niacinamide and azelaic acid are fine alongside it, and can help with the redness.
The bleaching problem
Benzoyl peroxide bleaches fabric. Towels, pillowcases, the collar of your T-shirt, and hair if it touches your hairline. It's a real nuisance, not a myth.
- Use white towels and pillowcases while you're using it.
- Let the product dry fully before your face touches fabric.
- Rinse washes off thoroughly, including along the hairline.
- Apply it in the morning if night-time use keeps ruining pillowcases.
Benzoyl peroxide for body acne
A 5% or 10% wash in the shower is the simplest way to treat chest, shoulders and back. Lather it on the affected areas, leave it for a minute or two while you wash your hair, then rinse. If your body spots are small, itchy and all the same size, they may not be acne at all: see fungal acne. More on body breakouts in back acne causes and treatments.
Where it fits in a routine
A simple acne routine with benzoyl peroxide:
- Morning: gentle cleanser, moisturiser, SPF.
- Evening: gentle cleanser, thin layer of benzoyl peroxide, moisturiser.
That's enough for a lot of people. If you have clogged pores as well as inflamed spots, add a salicylic acid product on alternate nights, or ask your GP about a retinoid. The minimal acne routine has more detail, and skin purging vs breaking out helps if you're unsure whether a new product is working.
References
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):664-667. (https://pubmed.ncbi.nlm.nih.gov/2948929/)
Boonchaya P, Rojhirunsakool S, Kamanamool N, et al. Minimum contact time of 1.25%, 2.5%, 5%, and 10% benzoyl peroxide for a bactericidal effect against Cutibacterium acnes. Clin Cosmet Investig Dermatol. 2022;15:403-409. (https://pubmed.ncbi.nlm.nih.gov/35300432/)
Reynolds RV, Yeung H, Cheng CE, et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol. 2024;90(5):1006.e1-1006.e30. (https://pubmed.ncbi.nlm.nih.gov/38300170/)
Nast A, Dréno B, Bettoli V, et al. European evidence-based (S3) guideline for the treatment of acne – update 2016 – short version. J Eur Acad Dermatol Venereol. 2016;30(8):1261-1268. (https://pubmed.ncbi.nlm.nih.gov/27514932/)
FAQs
What strength of benzoyl peroxide should I use?
2.5% or 5% for a leave-on gel. Trials found 2.5% worked as well as 10% on inflamed spots with less irritation. For a rinse-off wash, 5% to 10% makes more sense because contact time is short.
Can I use benzoyl peroxide every day?
Yes, once your skin has adjusted. Start every other night and build up to daily over two to three weeks.
How long does benzoyl peroxide take to work?
Around four to six weeks for a visible difference and two to three months for the full effect.
Can I use benzoyl peroxide with salicylic acid?
Yes, but not necessarily at the same time. Using both every night is often too drying. Alternating nights, or using a salicylic cleanser with a benzoyl peroxide gel, is easier on the skin.
Does benzoyl peroxide bleach towels?
Yes. It bleaches fabric and hair. Use white towels and pillowcases, and let it dry before your face touches fabric.
Can I use benzoyl peroxide while pregnant?
Topical benzoyl peroxide is generally considered one of the lower-risk acne options in pregnancy, but check with your GP or midwife before using any acne treatment.