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When an independent laboratory filed a citizen’s petition in March 2024, urging the FDA to recall and suspend the sale of acne products containing benzoyl peroxide after finding what it termed unacceptably high levels of benzene in acne products it tested, it ignited a range of reactions in the medical community and consumers. Responses ranged from fear to indifference, with even some dermatologists passing off the request as nonsense.

However, concerns about the potential for benzoyl peroxide-containing acne products to break down into benzene, a known human carcinogen, have been ongoing.

In recent months, as research has accumulated, so has a clearer picture of the risk. The FDA has taken action, although some contend the agency has not done enough, and experts involved are better focused — and sometimes in closer agreement — on how to move forward to increase safety for the products, considered one of the most effective topical acne treatments and the only effective remedy for many patients.

Medscape Medical News reached out to John S. Barbieri, MD, MBA, assistant professor of dermatology at Harvard Medical School and director of the Advanced Acne Therapeutics Clinic at Brigham and Women’s Hospital, both in Boston, and David Light, president and co-founder of Valisure, the independent laboratory in New Haven, Connecticut, that filed the petition, asking for an update of what they’ve found out in recent months (they both have published research recently), what they believe needs to be done moving forward, and their advice on how clinicians should be talking to their patients about the products.

“Based on the available evidence, I think this issue is unlikely to pose meaningful risk to those using benzoyl peroxide products,” said Barbieri, who has researched and written about the issue extensively. “I continue to routinely use benzoyl peroxide products for those with acne.” However, he’s adamant that more needs to be done to maximize the safety of the products, that patients need to be educated about precautions they can take, and that manufacturers need to focus on getting the benzene levels in their products to what he and others say is achievable — zero.

Product Heterogeneity

Researchers have found a wide range of levels of benzene in products. That’s good news, so to speak, in regard to fixing the problem. As Barbieri and Christopher Bunick, MD, PhD, associate professor of dermatology at Yale University School of Medicine, New Haven, Connecticut, wrote in a recent Viewpoint in JAMA Dermatology, “there has been considerable heterogeneity observed between brands and product lines, suggesting opportunities to improve formulation, production, and distribution practices to maximize the safety of benzoyl peroxide-containing products.”

The range of benzene found, for instance, in the Valisure analysis leading to the citizen’s petition was sometimes over 800 times the FDA’s conditional limit of 2 parts per million.

The JAMA paper also cites a study, published in May 2025, by Bunick, Light, and others, finding that cold storage may reduce benzene formation, and a study co-authored by Barbieri, which found that leave-on benzoyl peroxide products contained lower concentrations of benzene, possibly because they are often manufactured in smaller batches than washes “and thus may cool more quickly,” they wrote.

Recent Recalls

In March 2025, the FDA alerted the public and industry to the results of its testing of 95 acne products with benzoyl peroxide for possible benzene contamination, following the receipt of the Valisure test results. As a result of the FDA alert, six companies voluntarily recalled some of their products, and another company voluntarily recalled its product after its own testing.

FDA Input?

Under nonbinding FDA guidance issued in December 2023, benzene levels in products using carbomers (thickeners) should not exceed 2 parts per million.

Medscape Medical News reached out to the FDA, asking if the agency had any other information pertaining to developments in the manufacturing of benzoyl peroxide acne products. A spokesperson referred only to the March 2025 information about recalls and its finding that more than 90% of the benzoyl peroxide acne products it tested had undetectable or very low levels of benzene.

Manufacturers’ Mission

Manufacturers need to do more, Light and Barbieri agreed, to monitor benzene levels and reduce them.

“I’m quite supportive of the paper they wrote,” Light told Medscape Medical News, referring to the JAMA update co-authored by Barbieri and Bunick. “I appreciate their push on the manufacturers’ side,” a stance Light has taken from the start.

Information on exactly what the product manufacturers are doing, even after the March recalls and the FDA testing, is scarce, Light and Barbieri agreed.

(Light’s analyses have previously been the target of some criticism, contending he is mostly interested in winning lawsuits against companies and boosting profits. He has filed patents related to, among other areas, the prevention of the formation of impurities, including benzene, in drug products such as benzoyl peroxide-containing products. In response, Light said his goals have always been focused on public health and consumer protection. “Our analyses have not only been rigorously reviewed through the peer-review process in multiple journals,” he said, “but each of our five FDA Citizen Petitions on benzene contamination in major consumer product categories has been followed by testing and validation by regulators and companies that confirmed unacceptably high levels of benzene and initiated recalls.”)

The Consumer Health Products Association, a trade group that many of the benzoyl peroxide product manufacturers belong to, posted the following statement on its site after the citizen’s petition was filed last year: “Benzene is not intentionally added to any consumer product, and it is important that proper quality control measures are in place to both detect impurities and reduce potential contamination during the manufacturing process.” But it offered no more specific information about individual manufacturers’ procedures or attempts at improvements.

Beyond quality control measures, manufacturers must pay attention to shipping and distribution, which can affect benzene levels as temperatures rise, Barbieri said. “Consumer confidence is really important here,” he added.

Manufacturers should also transparently share their benzene data, Barbieri and Light agreed. Besides acne products, according to the FDA, hand sanitizers, aerosol antiperspirants, and sunscreen sprays have been recalled because of benzene concerns.

Empowering Patients

Meanwhile, clinicians can advise patients to take a number of steps to minimize the risk for benzene exposure, according to Barbieri and Light.

Discarding expired products or those that have been exposed to high temperatures — such as being left in a hot car — is one recommendation. Replacing products every 10-12 weeks is also probably wise, Barbieri said, but he concedes that more data is needed about the stability of the products at room temperature. Whether refrigerating the products is better than keeping them at room temperature hasn’t been fully researched, he noted.

Lowering the temperature does help with benzene formation, Light said. In his studies, he found that a single acne product incubated at 158 °C, similar to a hot car, released benzene at concentrations about 1270 times higher than the US Environmental Protection Agency threshold for cancer risk via long-term inhalation. He also cautions against storing the products in the bathroom medicine cabinet because of the higher temperatures.

In addition, consumers shouldn’t rely on “best products” lists based on analyses of benzene levels, Barbieri told Medscape Medical News, because the same product could have been purchased in different ways — such as picking it up from the store directly or ordering it online and then having it sit on a hot doorstep for hours. Be cautious using online retailers and pharmacies, he said, for those reasons — the products could have had potentially higher temperature exposure during shipping.

Ultraviolet exposure is similar to heat in its effects, Light pointed out. Barbieri said those who use leave-on products should consider sun protection, which, he added, is a useful general recommendation for acne management in general.

Looking Forward: Getting to Zero

While progress has been made, and awareness of the risks has increased, there’s work to be done, experts agreed. “It’s still an important and relevant issue,” Barbieri said. “We want to be doing as much as we can to mitigate the risk as much as possible. Even if the risk is 0.00001, if we can make it zero, we should make it zero.”

Barbieri and Bunick have reported no relevant disclosures. Light has filed patents related to the prevention of the formation of impurities, including benzene, in drug products, such as benzoyl peroxide products. The Journal of Investigative Dermatology study published in May 2025 was funded by Valisure.

Kathleen Doheny is a freelance journalist in Los Angeles.