Evaluation of Benzene Presence and Formation in Benzoyl Peroxide Drug Products

Journal of Investigative Dermatology

Clinical Summary

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What was studied

Laboratory testing of benzene in 111 over‑the‑counter benzoyl peroxide (BPO) products at room temperature by GC–MS, stability of a prescription‑encapsulated BPO at 2 °C and 50 °C, and airborne benzene during simulated face application with and without sub‑peak UV.

Key findings

Benzene ranged from 0.16 to 35.30 ppm in 111 OTC BPO products kept at room temperature. An encapsulated prescription BPO showed no apparent benzene at 2 °C but high formation at 50 °C, and benzene was detectable in air during use and rose substantially under UV below peak sunlight.

Study limitations

Airborne benzene concentrations and exposure durations were not quantified in the abstract, limiting exposure assessment. The face model used polymethyl methacrylate plates rather than human skin, and only one encapsulated prescription product was tested.

Clinical implications

BPO products can contain and generate benzene at room temperature and during use, with UV and heat boosting formation. Cold storage reduced formation in testing, while encapsulation alone may not prevent it; starting benzene content may not predict exposure.