Does Benzoyl Peroxide Contain Benzene? What the Testing Found

Benzoyl peroxide can break down into benzene, and heat speeds that up. An independent lab, Valisure, reported benzene in most of the benzoyl peroxide acne products it tested, with much higher levels after the products were kept warm for days or weeks. When the FDA ran its own tests on 95 benzoyl peroxide acne products, it found far less: more than 90% had undetectable or extremely low levels, and six had elevated levels, which led to retail recalls of specific lots. The agency said that even with daily use of those recalled products for decades, the risk of developing cancer from the benzene in them is very low. So no, your tube isn’t a reason to panic. It is a reason to keep it out of hot cars and steamy shelves and to throw it out once it expires.

What the lab reported

Benzene doesn’t get added to acne products. The concern is chemistry. Benzoyl peroxide is an unstable molecule, and one of the things it can break down into is benzene, a chemical that can raise cancer risk with long-term exposure.

Valisure, a private testing lab in Connecticut, filed a citizen petition with the FDA in March 2024 asking for an investigation and a market withdrawal of benzoyl peroxide products. Its summary of the petition gives these numbers:

• It ran its first round of tests on 175 acne products: 99 with benzoyl peroxide and 76 without, mostly salicylic acid or adapalene.
• 94 of the 99 benzoyl peroxide products contained benzene before any heating.
• All 76 products without benzoyl peroxide had no detectable benzene or levels below 2 parts per million (ppm), the limit regulators allow only when benzene can’t be avoided in making a drug.
• After 18 days at 50°C (122°F), a standard temperature for stress-testing medicines, 42 of 66 benzoyl peroxide products had more than 10 ppm, 17 had more than 100 ppm, and 2 had more than 1,500 ppm.
• At 70°C (158°F), which the lab used to stand in for a hot car, benzene also escaped from closed containers into the surrounding air.

The lab published parts of this work in the journal Environmental Health Perspectives, in a short paper testing seven products. A second Valisure-led paper in the Journal of Investigative Dermatology tested 111 over-the-counter products kept at room temperature and found benzene from 0.16 to 35.30 ppm. In the same paper, a prescription benzoyl peroxide product showed no apparent benzene formation when kept at 2°C (about fridge temperature) and high levels at 50°C. Its authors concluded that cold storage may greatly reduce benzene formation.

Keep in mind who did this work: one company’s lab, using heat on purpose, in support of a petition to pull benzoyl peroxide products off the market.

What the FDA found when it tested for itself

The agency started its own testing after it received the third-party results. On March 11, 2025, it reported on 95 benzoyl peroxide acne products, including every product the outside labs had flagged that it was able to buy at the time, plus others on the market. It used what it calls validated test methods. Six products had elevated benzene. More than 90% had undetectable or extremely low levels.

The companies behind the six agreed to voluntary recalls of specific lots. Those recalls are at the retail level, which means stores and online sellers pull the product. They don’t instruct shoppers to do anything with what they already own. The agency did point out that some of the six were close to expiring and recommended checking your products and throwing away anything past its expiration date.

The maker of Zapzyt Acne Treatment Gel also agreed to a voluntary recall after its own testing found elevated benzene. A recall covers the listed lots, not every bottle with that name, so check the lot number printed on yours.

Why the lab and the agency got such different numbers

Part of it is what each one measured. Valisure’s biggest numbers came from products it heated on purpose. The agency measured products as bought.

Part of it may be the testing itself. The agency has warned that unvalidated methods used by third-party labs can report much higher contaminant levels than are present. Chemists at the company Cambrex in Sweden found that a standard way of preparing benzoyl peroxide samples can break the molecule down during the test and create benzene that wasn’t there before. With the standard method they measured about 20 ppm. With their own method, about 0.20 ppm, roughly 100 times lower. That was raw benzoyl peroxide, not finished acne products, and the authors work for the company, so it settles nothing. It does show how much the method matters.

So how worried should you be?

Not very, going by the evidence so far. The agency’s own wording is that, even with daily use of the recalled products for decades, the risk of developing cancer from the benzene in them is very low.

Researchers have also looked at people. A review by dermatologists at the University of Calgary, published in Frontiers in Pediatrics, sums up the studies so far. One looked at more than 2.3 million patients with acne, another matched 79 people who reported using benzoyl peroxide against non-users and found no link to benzene in their blood, and two more used a database of over 132 million patients. None found a link between benzoyl peroxide and blood cancers or higher blood benzene. The reviewers also list what those studies can’t show: they didn’t measure how much product anyone used or for how long, and they mostly missed over-the-counter use. So the question isn’t closed, but nothing so far shows harm in people who use it.

How to store benzoyl peroxide

• Room temperature, not hot. The drug labels on the benzoyl peroxide washes below say to store them at 68 to 77°F (20 to 25°C).
• Not in the car. Valisure used 70°C to stand in for a hot car, and at that heat benzene escaped from closed containers. Don’t leave a tube in a glove box or a gym bag in a parked car.
• Not in the shower. The Calgary reviewers suggest moving products to a cooler spot while you shower and keeping them out of direct sunlight. In the Valisure-led face-model experiment, UV light below peak sunlight increased benzene formation, so a sunny windowsill is a bad home too.
• The fridge is an option, not a rule. The same review suggests keeping products refrigerated, and the cold-storage result above supports it. The labels themselves only ask for room temperature.
• Toss it when it expires. That’s the agency’s advice, and the easiest one to follow.

If you’d rather skip benzoyl peroxide

That’s a reasonable call. In Valisure’s testing, the acne products without benzoyl peroxide, mostly salicylic acid and adapalene, didn’t show the problem. They aren’t interchangeable with benzoyl peroxide or with each other, though. If benzoyl peroxide has been working for you, staying on it and storing it well is a perfectly sensible choice. Our benzoyl peroxide vs. salicylic acid comparison goes deeper on which suits which breakout.

What to reach for

Prices move constantly, so we link to live listings instead of printing a number that is wrong by the time you read it. Links go to Amazon, which is where a referral gets credited.

PanOxyl Acne Creamy Wash is about $10, though the price changes often. It’s benzoyl peroxide 4% in a wash you massage in for one to two minutes and rinse off, starting once a day. The label warns that it can bleach hair and dyed fabric, so use a white towel.

CeraVe Acne Foaming Cream Cleanser is the same strength, 4%, in a cream that foams. The label says to start with one use a day because it can dry skin.

Differin Gel is adapalene 0.1%, a retinoid that used to need a prescription. Differin’s directions are a pea-sized amount once a day over the whole face, not dabbed on one spot.

CeraVe Acne Control Cleanser has 2% salicylic acid with niacinamide and ceramides.

The Ordinary Azelaic Acid Suspension 10% is a cream-like formula for blemish-prone skin and uneven tone. The Ordinary says to apply a small amount morning and evening, patch test first, and not to pair it with strong acids or retinoids, so don’t layer it with the Differin.

If I Were You

If your benzoyl peroxide works and your skin likes it, keep using it. Move it out of the shower, keep it away from the car and the windowsill, and buy a fresh one once it expires.

If you own one of the products in the recall table, check the lot number on the box or crimp of the tube. If it matches, or the product is past its date, throw it out.

If the headlines put you off it for good, try the salicylic acid cleanser or Differin, one at a time.

If you live somewhere hot without air conditioning, the fridge is a fair place for your tube.

If you’re pregnant or breastfeeding, the PanOxyl label says to ask a health professional before use. Do that before starting or switching any acne product.

Bottom line

Benzoyl peroxide can form benzene, mostly when it gets hot. Government testing found elevated levels in six of 95 products and called the cancer risk very low. Store your tube cool, check lot numbers, toss anything expired, and if you’d rather switch, there are good alternatives. A board-certified dermatologist can help you choose if your acne needs more than one product. For building the rest of a routine, see our acne-prone skincare routine or the skin archive.