What We Really Know About Benzoyl Peroxide Acne Treatments and Benzene

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Acne products, specifically those containing benzoyl peroxide, are the latest beauty product category to come under question for possibly containing the carcinogen benzene. (Over the last few years, we have seen reports of potential benzene contamination with certain hand sanitizers, spray-on sunscreens, and aerosol dry shampoos, and some voluntary recalls.) Just like with those other product categories, no one is suggesting that all acne products are impacted (and you should most definitely keep wearing sunscreen). But one lab claims to have found benzene, which has been linked to cancer and blood disorders, in some popular acne products.

The independent lab Valisure says it has detected benzene in certain acne products containing benzoyl peroxide and filed a petition with the FDA requesting a recall for the affected products. Valisure studied more than 60 benzoyl peroxide (BPO) acne products, including over-the-counter and prescription treatments, and says they found that benzene can form within many of them at what they call “unacceptably high levels” — meaning higher than the FDA limit of 2 parts per million (ppm). (In simplified terms, parts per million is a unit of concentration meant to measure the amount of a specific substance in a mixture.)

According to a statement issued by Valisure, these “on-market BPO products can form over 800 times the conditionally restricted FDA concentration limit of 2 parts per million for benzene, and the current evidence suggests that this problem applies broadly to BPO products currently on the market.” Valisure also says it found that the amount of benzene increased when products were exposed to high temperatures for stability testing. According to Valisure’s findings, David Light, president of Valisure, told Allure, that these benzoyl peroxide-containing acne products may “make benzene over time, whether you heat [the product] up or whether it just sits on your medicine cabinet for a long time. The really important point on what we’re finding broadly with these benzoyl peroxide products is that sometimes they have … a significant amount of benzene even just sitting on the shelf.”

The acne products do not appear to be contaminated with trace benzene, rather “the benzene [may be] coming from decomposition of the active ingredient benzoyl peroxide,” explains cosmetic chemist Kelly Dobos. This is different from “recent examples of benzene found in sunscreen and other spray products, [in which possible benzene contamination was] linked to trace contamination of propellants. In hand sanitizers, trace levels [of benzene] were linked to residual solvent used in the manufacture of the polymers used to turn ethanol into a gel,” she explains. Valisure’s study suggests that subjecting some benzoyl peroxide-containing acne products to increased temperatures — between 99 and 150 degrees Fahrenheit (an approximation to the temperature of a hot car) — might accelerate that reaction, Dobos explains.

Light tells Allure that the stability testing Valisure conducts does not directly replicate that of consumer conditions, like leaving a bottle of acne treatment in your bathroom during a daily hot shower, but rather a “condensed” or sped-up version to represent what a product could feasibly undergo during the typical three-year life cycle in which products are supposed to be shelf-stable — like storing a product at more than 150 degrees for over 12 hours. They also found that benzene may be present in the air around the products, not just in them.

Ahead, here’s what you need to know about these findings and how they may impact the products you use to treat acne.

Meet the experts:

What is benzene?

As noted by the CDC, benzene is a chemical that can be manmade or formed naturally. The CDC shares that you can encounter benzene in everything from forest fires and gasoline to furniture wax and detergent; cigarette smoke is one of the major exposures people encounter in day-to-day life. Benzene is classified as a group A carcinogen by the Environmental Protection Agency (EPA) and has been linked to cancer, including leukemia. Group A carcinogens are simply classified as “carcinogenic to humans.”

Benzene has been an issue in the beauty industry before. In 2022, 32 aerosol dry shampoos and dry conditioners were voluntarily recalled due to possible benzene contamination. Other aerosol products, including sunscreen sprays and spray deodorants, as well as non-aerosol hand sanitizers, have also come under industry scrutiny for possible benzene contamination.

Why is benzene in acne products?

Benzene isn’t in acne products, per se, and you won’t find it on any ingredient lists; the question is whether it may be a chemical byproduct of benzoyl peroxide that can become present when formulas break down. Cosmetic chemist Perry Romanowski says that the potential breakdown of benzoyl peroxide into benzene does not happen when products are stored as directed, like at room temperature. “The lab that looked at benzene recently used excessive storage conditions to coax out as much benzene as they could,” he says. “Despite what the lab says, no one is going to store their anti-acne products in a car that is going to get to 70 degrees Celsius for weeks on end.”

However, Christopher Bunick, MD, a board-certified dermatologist and associate professor of dermatology for the Yale School of Medicine — who studies benzene contamination in personal care products — says, “Here, benzoyl peroxide itself is unstable when placed in currently available formulations and/or vehicles and breaks down into the carcinogen benzene.” According to Dr. Bunick, the breakdown to benzene happens in the bottle or packaging, though the time it takes to break down may vary. “At room temperature it could be days to weeks or longer, and that will depend on the formulation and the storage parameters.”

Should we be worried?

That’s up for debate, depending on who you ask. On one hand, benzene is classified as a carcinogen. “It’s not a, ‘Maybe this is bad for you.’ Benzene has been known to cause cancer or significantly elevate the risk of cancer in human beings for decades,” explains Light. The International Agency for Research on Cancer (IARC), part of the World Health Organization, classifies benzene as “carcinogenic to humans,” as does the US National Toxicology Program.

“Long-term industrial exposure, meaning workers in manufacturing who are exposed frequently over tens of years to benzene, has been linked to cancer,” Dobos says. “I’d like to examine all the test methods and data [of the Valisure study], but some of the high numbers referenced are coming from testing of products that were subjected to high temperatures accelerating the breakdown of benzoyl peroxide into benzene.”

Dermatologists Allure spoke with are skeptical about taking benzoyl peroxide off the table entirely, too. “We need more data,” says Caren Campbell, MD, a board-certified dermatologist in San Francisco. “Even if the breakdown of benzoyl peroxide releases benzene, the penetrability of it through the skin has been questioned by toxicologists [previously] and the apples-to-apples comparison of the data to real life is also questioned by these reputable toxicologists.”

Dr. Campbell typically recommends patients use benzoyl peroxide as a face wash at a low percentage of five percent or less, versus having it sit on the skin, so they get the acne-fighting benefits of benzene without its potential for irritating the skin. “This is what I’ve always recommended and frankly, this is also a way to limit the time on the skin and limit the concentration if more data is discovered showing it’s an issue,” she says. Certain types of acne respond differently to certain topicals, though Dr. Campbell does advise patients to avoid benzoyl peroxide if they are pregnant, breastfeeding, or trying to conceive.

Dr. Marisa Garshick, a board-certified dermatologist in New York and New Jersey, says you don’t need to panic if you’ve been using benzoyl peroxide products. “Importantly, clinical studies of benzoyl peroxide have not been found to show an increased risk of cancer with use of benzoyl peroxide,” she says. “Additionally, the lab conditions may not accurately reflect real-life conditions so they can be difficult to interpret.” Dr. Garshick advises waiting to see how the FDA interprets and verifies the findings, if at all.

If you’re currently taking a prescription benzoyl peroxide product for acne, you can reach out to your doctor for guidance. There are also plenty of acne products out there that don’t contain benzoyl peroxide, such as those formulated with salicylic acid, sulfur, or a retinoid like adapalene.

It’s also important to note that we are exposed to benzene in our environment every day, says Dobos. “Exposure occurs when cooking or fueling our cars, and smoking and vaping have been found to substantially increase the amount of benzene inhaled.”

Romanowski agrees. “The amount of exposure you get from cosmetic products is inconsequential compared to the rest of your exposure,” he shares. “Benzoyl peroxide has been safely used in anti-acne products since the early 1970s. The fact that a lab found that through excessive heating of a product you can detect levels of benzene says nothing about the safety of products that use benzoyl peroxide.”

What happens next?

The FDA received Valisure’s petition and says they “generally do not comment on pending petitions.” However, an FDA spokesperson told Allure that “the FDA is committed to ensuring drugs Americans use are safe, effective, and of high quality. The agency acts on information provided from a variety of sources, such as that provided by Valisure, but such data must be verified as accurate and reproducible before it can be utilized to make regulatory decisions such as recommending product sale suspensions and recalls. The agency will continue to provide updates to the public regarding benzene in drug products, as appropriate.” (Over-the-counter acne treatments with benzoyl peroxide are classified as a drug by the FDA.)

Valisure says it found benzene in topical and treatment products from big names including Proactiv, Clinique, Clearasil, Target’s in-house line Up & Up, and more, including prescription benzoyl peroxide products. Allure reached out to the aforementioned brands for comment on Valisure’s claims.

In response, Reckitt, the parent company of Clearasil, says, “Reckitt is confident that all Clearasil products, when used and stored as directed on their labels as intended, are safe. The safety and quality of our products is our top priority and we work closely with regulators around the world to ensure our products are safe and effective for their intended use. The products and their ingredients are stable over the storage conditions described on their packaging which represent all reasonable and foreseeable conditions. The findings presented by an independent lab today reflect unrealistic scenarios rather than real-world conditions.”

A representative for Clinique says, “At Clinique, rigorous safety is our highest priority. Benzene is not used as an ingredient in any product across the Clinique brand portfolio. Benzoyl peroxide, an FDA-approved and commonly used ingredient for acne treatment, is not benzene. Clinique uses benzoyl peroxide in one product. This product, like all of our products, is safe for use as intended.” At press time, representatives for Proactiv and Target had not responded to Allure‘s request for comment.

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