Benzene in consumer products

By Emily Margosian, Assistant Editor, April 1, 2025

From dry shampoo to acne medication — benzene, a known human carcinogen, has been detected in multiple cosmetic and cutaneous products over the past several years.

The International Agency for Research on Cancer — a division of the World Health Organization (WHO) — classifies benzene as a group 1 carcinogen (known to cause cancer in humans), placing it in the same category as asbestos, radiation, and formaldehyde. Its detected presence in a wide range of consumer products has raised alarm bells among consumers, regulators, and the scientific community.

Recently, reports have emerged that certain acne products containing benzoyl peroxide have been found to contain elevated levels of benzene. These reports have raised questions — and concerns — from both dermatologists and patients about the safety of benzoyl peroxide and how to interpret the recent findings.

Ringing the alarm: A timeline of benzene’s detection in consumer products

In May 2021, Connecticut testing laboratory Valisure reported the presence of benzene in 69 different brands of sunscreen and after-sun care products. Many popular brands subsequently issued voluntary product recalls.

In October 2022, a citizen petition to the FDA on benzene in dry shampoos was filed after 148 batches of dry shampoo across 34 unique brands were found to show short-term benzene levels of 1,600 parts per million (ppm) — 90 times higher than the EPA threshold for increased cancer risk.

Many products containing benzene were pulled from shelves and voluntarily recalled following news reports in 2023 and 2024. A complete list of product recalls is available on the FDA website.

In March 2024, the “BPO bombshell” was dropped when an unsafe level of benzene was reported in a range of anti-acne skin care treatments. Valisure filed a petition with the FDA calling for an investigation and recall of the affected products, all of which contained benzoyl peroxide (BPO).

Benzene in acne products

Per Valisure’s testing, certain acne products that contain benzoyl peroxide were found to produce high levels of benzene when exposed to extreme heat. It has been suggested that this process can occur during manufacturing, shipping, and storage as products are exposed to a range of temperatures.

“These findings are potentially concerning as benzoyl peroxide use is so widespread,” said Shari Lipner, MD, PhD, FAAD, associate professor of clinical dermatology and associate attending physician at New York-Presbyterian Hospital/Weill Cornell Medical Center.

In October 2024, a subsequent study conducted by Valisure found that dozens of over-the-counter BPO acne products had detectable levels of benzene, even when taken directly from store shelves (doi: 10.1016/j.jid.2024.09.009).

“It is concerning if there are meaningful levels of benzene in benzoyl peroxide products being used by patients with acne or other skin diseases,” said John Barbieri, MD, MBA, FAAD, director of the Advanced Acne Therapeutics Clinic at Brigham and Women’s Hospital and instructor in dermatology at Harvard Medical School. “The Valisure Citizen’s petition and publication in Environmental Health Perspectives highlighted that benzoyl peroxide products can develop very high levels of benzene at 50 degrees celsius and more modest levels of benzene when incubated at 37 degrees celsius. Their more recent publication in the Journal of Investigative Dermatology also found low levels of benzene in some products even at the time of purchase, with substantial heterogeneity between products and brands.”

“There are many things in this world that change chemistry if you cook them. It’s an artificial situation, because people aren’t going to take their acne medication and put it in the oven.”

According to the 2024 JID study, among 111 benzoyl peroxide (BPO) products purchased from various U.S. retailers, 34% had benzene above the conditionally restricted FDA limit of 2 ppm. Concentrations ranged from 0.16 ppm to 35.3 ppm. Researchers claim that cold storage significantly reduces benzene formation, suggesting the need to recommend refrigeration until alternate BPO formulations are developed.

In response to the new research published in JID, in November 2024, the AADA asked the FDA to update the public on the study’s findings. The FDA released its findings on March 11, indicating that more than 90% of tested products contained undetectable or extremely low levels of benzene. However, some products did show elevated levels, leading to voluntary recalls. The FDA also announced that it will publish the full results of its testing in peer-reviewed journals in the coming months.

Regardless, questions persist about the findings released by Valisure.

“Valisure’s findings are subject to important limitations. We do not know when the benzoyl peroxide products were originally manufactured, and if they expired. The products were also exposed to conditions that likely are not replicated in real-life use,” said Dr. Lipner.

“Products have a very specific temperature range for use that ensures the stability of ingredients,” said Zoe Diana Draelos, MD, FAAD, from Dermatology Consulting Services, PLLC. “To take a tube of acne medicine and expose it to high heat violates the conditions under which the product is known to be stable. There are many things in this world that change chemistry if you cook them. It’s an artificial situation, because people aren’t going to take their acne medication and put it in the oven.”

“Valisure has yet to provide any evidence of meaningful benzene formation with appropriate storage at room temperature or cooler conditions,” added Dr. Barbieri. “While the recent Journal of Investigative Dermatology publication has been framed as demonstrating benzene formation at room temperature, we do not know whether the benzene identified in these products might instead have occurred due to higher temperature exposure during formulation or distribution.”

Safe storage of benzoyl peroxide products

Experts recommend storing acne products that contain BPO in a cool, dry environment and not exposing them to excessive heat.

“It may be prudent to keep these products in the refrigerator, and keep them out of the bathroom, car trunk, or glove compartment,” said Dr. Lipner. “We do not know if benzene can be released from benzoyl peroxide during real-world use without doing formal well-controlled experiments. However, based on the available evidence, it is prudent to recommend that patients keep their products at room temperature or below for the time being.”

Dr. Draelos also recommends patients keep their BPO products appropriately sealed in addition to cool storage. “They should always be stored with a lid screwed on because the ingredients — especially benzoyl peroxide — can oxidize. Patients should also discontinue use of any products after the expiration date. Expired medicines aren’t safe, and if they haven’t been cared for under the proper environmental conditions, they’re not safe either.”

“We should also be thoughtful about acne products that are mailed to patients, such as those from online retailers, as these might be exposed to higher temperatures during shipping or if they sit outdoors in hot weather after delivery,” added Dr. Barbieri.

Addressing patient concerns

While the manipulation of benzoyl peroxide via extreme heat does result in the release of benzene, under typical usage conditions it is unlikely that significant benzene release will occur, new research suggests.

A recent JAMA Derm study found no meaningful association between time stored at room temperature, as determined by how close products were to their expiration date, and benzene formation. They estimated that for each 100 days of storage at room temperature benzene levels would rise by <1ppm (doi:10.1001/jamadermatol.2024.6443).

Likewise, despite benzene exposure’s well-documented association with various cancers, a retrospective study published in JAAD found no association between benzoyl peroxide use and higher cancer risk (doi: 10.1016/j.jaad.2024.07.1504).

Another recent study using data from the National Health and Nutrition Examination Survey showed no evidence for an association between benzoyl peroxide use and increased blood benzene levels (doi: 10.1016/j.jaad.2024.06.050). According to Dr. Barbieri, one of the study’s authors, these results should provide reassurance to patients in the safety of standard-of-care BPO use. “It is important to keep in mind that transdermal absorption of benzene is minimal, so the expected risk would be due to aerosolization and inhalation. Our work using the National Health and Nutrition Examination Survey (NHANES) does not show any link between benzoyl peroxide use and increased blood benzene levels. In addition, our work using TriNetX does not support any risk of hematologic or solid organ malignancy with benzoyl peroxide use. From a practical standpoint, even if benzene is present at some of the highest levels detected by Valisure in their recent study published in the Journal of Investigative Dermatology, it is unlikely that the absolute exposure is going to be clinically significant in the context of other benzene exposures in our daily lives.”

“In the absence of more data around harm or safety risk, dermatologists should reassure patients about the likely safety of benzoyl peroxide products when used correctly and emphasize the importance of proper storage.”

Patients who are concerned about the safety of benzoyl peroxide may be offered alternatives, such as topical retinoids, salicylic acid, or azelaic acid. However, a true substitution is elusive. “This is a big challenge. There is no direct alternative to benzoyl peroxide and if we are not using benzoyl peroxide, we also should not really be using topical antibiotics either due to the risk of antibiotic resistance. While topical retinoids, clascoterone, salicylic acid, and azelaic acid are other topical acne treatments that could be used instead of benzoyl peroxide, often multimodal therapy is required to achieve clear skin and these alone might not be enough for many with acne,” said Dr. Barbieri. “This ultimately means that we will be using more systemic treatments like oral antibiotics, spironolactone, and isotretinoin that have their own risks — including cancer — that must be weighed when evaluating the risks and benefits of using versus avoiding benzoyl peroxide.”

“While there are many topical acne ingredients, there really isn’t a perfect alternative to benzoyl peroxide,” agreed Dr. Lipner. “The advantage of benzoyl peroxide is that its efficacy has been proven in well-controlled clinical trials, and it effectively prevents antibiotic resistance to topical and oral antibiotics.”

The Academy provides talking points for discussing this issue with patients. Access key messages for discussing benzene found in acne products.

Benzoyl peroxide and acne management

Experts advise that it is not necessary to avoid BPO in the management of acne at this time. “While Valisure’s findings warrant further investigation and should be taken seriously, dermatologists should carefully weigh the current lack of conclusive evidence linking benzoyl peroxide use to health risks with its well-established efficacy in acne treatment,” said Dr. Barbieri. “I don’t think it is practical or necessary to avoid benzoyl peroxide at this time, but we must continue to monitor this issue as more data become available.”

“I think we should focus on counseling patients about correct storage of benzoyl peroxide products at room temperature or refrigerated,” said Dr. Lipner. “Expiration dates should also be checked, and anything past the expiration date should be discarded. If we use benzoyl peroxide responsibly, then it continues to have an important role in the acne treatment armamentarium.”

Academy response: What’s next?

The AADA continues to closely track this issue. “We have requested that the agency keep us informed with regular updates on its investigation into Valisure’s claims, especially given the frequent prescribing of benzoyl peroxide products by dermatologists for acne treatment,” said Jillian Winans, AADA associate director of health policy and payment.

“It is our responsibility to explain the Valisure data in a manner that our patients will understand. I tell my patients that there is evidence showing that benzene can be found in heated benzoyl peroxide products,” said Dr. Lipner. “However, there are small amounts of benzene in the environment at baseline and high benzene levels are unlikely if benzoyl peroxide is stored at room temperature or below.”

“In the absence of more data around harm or safety risk, dermatologists should reassure patients about the likely safety of benzoyl peroxide products when used correctly and emphasize the importance of proper storage. We also should advocate for ongoing research to identify the best formulation, storage, and distribution practices, which can then be used to set industry standards to improve the safety of benzoyl peroxide-containing products,” advised Dr. Barbieri.

Additional DermWorld Resources