Benzoyl Peroxide Acne Treatments May Degrade into Carcinogenic Benzene: Study

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 benzoyl peroxide drug products. Recent research in the

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Journal of Investigative Dermatology, 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 benzoyl peroxide 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 benzoyl peroxide into benzene has been a topic of concern in dermatology. Our research demonstrates that benzoyl peroxide 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 benzoyl peroxide 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 benzoyl peroxide, including potential risks associated with UV exposure.”

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 benzoyl peroxide 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 benzoyl peroxide drug products.

Reference: Evaluation of Benzene Presence and Formation in Benzoyl Peroxide Drug Products Kucera, Kaury et al. Journal of Investigative Dermatology, Volume 0, Issue 0