Acne treatments bought off the shelf contained high levels of benzene

Dozens of over-the-counter acne products had very high levels of benzene, a known carcinogen, even when they were removed from store shelves, researchers found.

Among 111 benzoyl peroxide (BPO) products purchased from various retailers in the United States, approximately one-third (34%) contained benzene above the FDA’s “conditionally restricted” limit of 2 ppm, reported Kaury Kucera, PhD, of Valisure, an independent laboratory in New Haven, Connecticut, and colleagues.

Concentrations varied widely — from 0.16 ppm to 35.3 ppm — and studies showed that there is “no safe level of exposure to benzene,” they noted in the report. Journal of Investigative Dermatology.

Additionally, researchers found that the products rapidly degraded benzene when exposed to UV levels similar to sunlight, at a rate of approximately 4.36 ppb per hour. “This suggests that reasonable levels of UV exposure can generate significantly more benzene than the high temperature reasonably expected in transport,” they wrote.

They also performed cold testing on a prescription product – 5% Benzoyl Peroxide Cream (Epsolay), the first BPO cream approved by the FDA to treat rosacea – which “supports the expectation that the Cold storage stabilizes BPO formulations and supports the American Acne and Rosacea Society’s interim guidelines that suggest refrigerated storage of BPO products.

“Our research demonstrates that BPO products can generate benzene at typical ambient and storage temperatures, while cold storage significantly reduces this formation,” said co-author Christopher Bunick, MD, PhD, of the University from Yale in New Haven, Connecticut, in a statement. .

“These results suggest the need to recommend refrigeration of BPO products throughout the supply chain – from manufacturing to patient use – to limit exposure to benzene,” Bunick continued. “Until formulations are developed to prevent benzene formation, refrigeration may provide a practical solution to minimize unnecessary exposure.”

He added that dermatologists “should continue to advise patients on the appropriate use of BPO, including the potential risks associated with UV exposure.”

Valisure has previously reported the presence of benzene in BPO products at body temperature and at expected higher temperatures during storage and transportation. Based on these findings, the company sent the FDA a citizen petition calling on the agency to take actions such as revising industry guidelines, requesting recalls, and suspending them.

This current study goes further by performing analysis at room temperature and testing UV light conditions. It was also found that with the prescription cream, benzene formed linearly over time when tested at temperatures of 50ºC (122ºF).

This is despite the fact that this product is encapsulated – a method used to stabilize BPO products – which however suggests it may not work, they reported.

The instability of BPO products is similar to the case of ranitidine products, the researchers said, for which Valisure had previously shown high levels of nitrosodimethylamine (NDMA) degraded on store shelves or after exposure to heat .

Valisure also discovered that some metformin products degraded to NDMA, leading to recalls. It has detected benzene in other consumer health products, including hand sanitizers, sunscreens, deodorants and dry shampoos.

Richard Gallo, MD, PhD, of the University of California, San Diego, who was not involved in the study, said in a press release that the research was “carefully conducted” and “should bring to an end to the question of whether benzene is present in skin care products containing BPO.

“It is now important that further studies are conducted to determine whether the presence of this potential carcinogen in BPO-containing medications translates into an increased risk of cancer,” Gallo said.