Benzene Formation in Benzoyl Peroxide: What Dermatologists Need to Know in 2025, with John Barbieri, MD, MBA

The risk of benzene in products containing benzoyl peroxide was a hot topic of discussion in dermatology for 2024, primarily as the result of a report from independent testing company Valisure suggesting the known human carcinogen could form at high levels in many common acne products.1

According to the March 2024 report from Valisure, tests indicated on-market benzoyl peroxide products can form over 800 times the conditionally restricted FDA concentration limit of 2 parts per million for benzene and suggested this problem applies broadly to benzoyl peroxide products on the market at the time. Additionally, a release from Valisure suggested high levels of benzene were also detected in the air around incubated benzoyl peroxide products. This report, released 2 days before the 2024 American Academy of Dermatology (AAD) annual meeting, was thrust into the spotlight of the dermatology community.1

Less than a month before the 2025 AAD annual meeting, John Barbieri, MD, MBA, and colleagues published new data in JAMA Dermatology detailing variation in benzene levels between products and brands based on formulation characteristics as well as other factors that might influence benzene formation.2

The study assessed 111 over-the-counter benzoyl peroxide products tested by Valisure. Products were categorized by use (leave-on vs. wash), benzoyl peroxide concentration, product age (days until expiration), and formulation factors, including hot processing, antioxidants, and acidity.2

Results indicated that leave-on products had significantly lower benzene concentrations (coefficient, -5.83; 95% CI, -8.15 to -3.51). There was no significant link between benzoyl peroxide concentration and benzene levels, but a weak association was noted with product age (coefficient, -0.010; 95% CI, -0.019 to -0.001). Study results suggested hot processing increased benzene concentrations (coefficient, 7.34; 95% CI, 5.04 to 9.64), while butylated hydroxytoluene was associated with decreased benzene levels (coefficient, -8.15; 95% CI, -13.03 to -3.26). Additionally, benzoic acid showed a trend toward lower benzene concentrations but was not statistically significant (coefficient, -5.16; 95% CI, -10.54 to 0.23).2

Following the release of this publication, we sat down with Barbieri to learn more about the potential risk of benzene formation in benzoyl peroxide products, how dermatologists should navigate patient concerns, and what the community has learned from this experience.

Relevant disclosures for Barbieri include Dexcel Pharma and Honeydew Care.

References:

1. Valisure. VALISURE detects benzene in benzoyl peroxide. Valisure. March 6, 2024. Accessed March 2, 2025. https://www.valisure.com/valisure-newsroom/valisure-detects-benzene-in-benzoyl-peroxide.

2. Barbieri JS, Rubin CB, Pham JP, Wong M. The Role of Formulation in Benzene Formation in Benzoyl Peroxide Products. JAMA Dermatol. Published online February 12, 2025. doi:10.1001/jamadermatol.2024.6443.