Benzoyl Peroxide Acne Drugs Lack Stability and Degrade into Carcinogenic Benzene Including When Kept at Room Temperature, New Study Finds

Investigators have determined that a substantial portion of topical benzoyl peroxide (BPO) acne and rosacea treatments currently on the market are unstable and contain unacceptably high levels of benzene, a known human carcinogen. Degradation of these products and formation of benzene appear to occur when sitting on shelves at room temperature, at elevated temperatures, and when exposed to ultraviolet (UV) levels representative of sunlight. Drug stabilization techniques like encapsulation do not appear to prevent the formation of benzene in BPO drug products. Groundbreaking research opens in new tab/window in the Journal of Investigative Dermatology opens in new tab/window, published by Elsevier, details the findings of this study.

The study also showed that in addition to elevated temperatures expected during use and transportation, exposure to UV light at outdoor levels is another concerning mechanism through which BPO drug products degrade into benzene, and one that appears to occur more rapidly than heated storage and transportation conditions. These products are frequently used by consumers over extended periods of time, thereby likely increasing their exposure to benzene; there is no safe level or duration of exposure to benzene.

Co-investigator Christopher G. Bunick, MD, PhD, Department of Dermatology and Program in Translational Biomedicine, Yale University School of Medicine, New Haven, CT, explains, “The potential degradation of BPO into benzene has been a topic of concern in dermatology. Our research demonstrates that BPO products can generate benzene at typical room and store shelf temperatures, while cold storage significantly reduces this formation. These findings suggest a need to recommend refrigeration of BPO products throughout the supply chain—from manufacturing to patient use—to limit benzene exposure. Until formulations are developed to prevent benzene formation, refrigeration may serve as a practical solution to minimize unnecessary exposure. Additionally, dermatologists should continue to advise patients on the appropriate use of BPO, including potential risks associated with UV exposure.”

BPO is a diacyl peroxide with bactericidal activity used in topical drug products up to 10% concentration available through prescription or over the counter for treatment of acne and rosacea. Acne drug products can also be formulated as a combination of drug products including BPO. Product types include wash-away cleansers and topical creams, gels, and lotions that are left on the skin for long periods of time.

Mass spectrometry methods were used to detect benzene in 111 new, unopened products stored at room temperature on shelves of major US retailers, and the air surrounding them with and without UV exposure. It is the first time BPO drug products have been shown to degrade into benzene via a mechanism other than heat, and furthermore, it shows that benzene formation can occur independently of the starting benzene concentration in new or cold temperature stored BPO drug products.

Lead investigator David Light, Co-Founder and President of Valisure, LLC, New Haven, CT, and Affiliate Professor at Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Long Island, NY, notes, "The discovery of benzene formation in benzoyl peroxide acne treatments presents a potentially serious public health risk. Our research demonstrates that these products, widely used by consumers of all ages, can potentially contain or generate concerningly high levels of benzene, particularly under common environmental conditions. This issue highlights the critical importance of rigorous independent testing of drug products to help protect consumers from harmful contaminants or degradation products."

Noted expert Richard L. Gallo, MD, PhD, Department of Dermatology, University of California San Diego, CA adds, “This carefully done analysis should put to rest the question of whether benzene is present in skin care products that contain BPO. It is now important that further studies be conducted to determine if the presence of this potential carcinogen in drugs with BPO translates into any increased risk of cancer.

Commenting on the study, Steve Xu MD MSc, Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, notes, “As the first dermatologist to publish on consumer complaints related to personal care products submitted to the Food and Drug Administration’s Center for Food Safety and Applied Nutrition’s Adverse Event Reporting System, I have long been concerned about the public health safety of these lightly regulated products available in retailers worldwide. BPO products for acne are now the newest addition to a growing list of products that have been recalled or raise safety concerns joining formaldehyde releasing hair care products, benzene contaminated deodorants, and phthalates in shampoos.”

Notes for editors

The article is “Evaluation of Benzene Presence and Formation in Benzoyl Peroxide Drug Products,” by Kaury Kucera, Nicola Zenzola, Amber Hudspeth, Mara Dubnicka, Wolfgang Hinz, Christopher G. Bunick, Michael Girardi, Arash Dabestani, and David Y. Light (https://www.doi.org/10.1016/j.jid.2024.09.009 opens in new tab/window). It appears online in the Journal of Investigative Dermatology, published by Elsevier.

The article is openly available for 60 days at https://www.jidonline.org/article/S0022-202X(24)02155-9/fulltext opens in new tab/window.

The full text of the article is also available to credentialed journalists upon request; contact Theresa Monturano at +1 215 239 3711 or [email protected] opens in new tab/window. Journalists wishing to interview the authors should contact Colleen Moriarty, MS, Director, Media Relations, Yale School of Medicine, Office of Communications, at +1 203 376 4237 (mobile), [email protected] opens in new tab/window, or Karrah Goldberg, MPS, Chief of Staff, Valisure, at [email protected] opens in new tab/window.

The work and analysis described in this study were funded and resourced by Valisure, LLC including the use of Valisure’s proprietary database. Valisure, LLC or its wholly owned subsidiaries are contracted as consulting experts for matters related to carcinogenic impurities and have filed patents related to quality scoring drug products in which impurities are a factor, independent certification of drug products where impurities are a factor and prevention of formation of impurities, including benzene, in drug products that include benzoyl peroxide.

About the Journal of Investigative Dermatology

The Journal of Investigative Dermatology opens in new tab/window (JID) is the official journal of the Society of Investigative Dermatology and the European Society for Dermatological Research. JID publishes high impact reports describing original research related to all aspects of cutaneous biology and skin diseases. Descriptions of important findings that result from basic, translational, or clinical research are published. Clinical research can include, but is not limited to, interventional trials, genetics studies, epidemiology, and health services research. www.jidonline.org opens in new tab/window

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