Study shows benzoyl peroxide products on store shelves may already contain benzene
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Key takeaways:
- A total of 111 benzoyl peroxide products stored at room temperature were substantially contaminated with benzene.
- 38 of the 111 products contained benzene concentrations that exceeded the FDA’s limit.
A new study confirmed previous findings that acne products containing benzoyl peroxide have high levels of cancer-causing benzene which are not stabilized by encapsulation techniques.
In March, an independent laboratory called Valisure released a report stating that acne treatments containing benzoyl peroxide (BPO) developed high levels of benzene, a known carcinogen, when handled or stored at higher temperatures.
Acne products containing benzoyl peroxide have high levels of cancer-causing benzene which are not stabilized by encapsulation techniques. Image: Adobe Stock.
The report detailed that both over-the-counter and prescription acne products with BPO can form more than 800 times the restricted FDA concentration limit of 2 parts per million (ppm) for benzene, raising high levels of concern among dermatology practitioners.
On Oct. 7, a new study published in The Journal of Investigative Dermatology by Kaury Kucera, PhD, of the Arnold & Marie Schwartz College of Pharmacy and Health Sciences at Long Island University, as well as other researchers including those from Valisure, confirmed these findings.
After investigating the native levels of benzene in sealed products stored at room temperature, the researchers of the study found that 111 BPO drug products “appear to be substantially contaminated with benzene when tested shortly after being acquired off the shelf,” the authors wrote.
The benzene levels found in these products ranged from 0.16 ppm ± 6% to 35.3 ppm ± 2% with 38 of the 111 products containing benzene concentrations that exceeded the FDA’s 2 ppm limit.
Since neither the source region nor the age of the products contributed to the presence of benzene, and certain brands as well as product types within those certain brands consistently had higher amounts of benzene than others, the authors believed that the formulation itself is to blame. However, they also wrote that this observation is anecdotal due to the small sample size of the study.
The study also investigated how effective encapsulation of the BPO products was in preventing the formulation of benzene. The authors evaluated this by incubating Epsolay (Galderma), a topical BPO acne cream, in both cold and hot temperatures.
Results showed that BPO was stabilized when stored in cold temperatures but not when stored in hot temperatures. When stored for 2 weeks in 50°C temperatures, Epsolay formed about 9 ppm of benzene per day, reaching 2 ppm within approximately 5 hours. After 2 weeks of being incubated at 50°C, Epsolay contained 130 ppm of benzene.
Using a face model experiment, the study also evaluated how BPO topicals react to the environment, including ultraviolet (UV) exposure.
In the first face model experiment, the researchers thinly spread 50 mg to 55 mg of Proactiv Renewing Cleanser (Alchemee/Taro Pharmaceutical Industries) with 2.5% BPO on 12 dermatology plates and incubated these plates in a dark chamber heated at a body temperature of 37°C and containing fans to regulate air flow for 24 hours.
Results showed that the average benzene concentration rose 1.96 parts per billion (ppb) in the first 15 minutes and 4.31 ppb in the last 15 minutes. This finding led the authors to conclude that approximately a total of 6 ppm of benzene evaporates from 630 mg of contaminated BPO products.
In the second face model experiment, the researchers spread 54.5 mg of a BPO drug product on a single plate and incubated the sample for 2.5 hours at 37°C with a UVA/B lamp. The lamp was turned on after 15 minutes and remained on for 135 minutes, simulating approximately one-third of peak ambient sun exposure.
Results showed that about 4.36 ppb of benzene is generated per hour of UVA/B exposure, which equals 269 ppm of benzene being evaporated into the air after 2 hours.
According to the authors, all these findings are concerning considering the elevated temperatures that these products encounter during transportation and the UV exposure they experience when applied to the skin.
“In the interest of public health, further study and regulatory and industry actions, such as recalls, are warranted,” they concluded.
Perspective
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This is an important issue that we should take seriously; however, we also must not overreact.
BPO is a foundational acne treatment without any clear alternative and there is currently no evidence to support that routine use of BPO-containing products for acne is associated with meaningful risk of benzene in the blood or increased risk of cancer, according to two recent studies published in JAAD.
It is important to note that we do not know how the tested products were produced, transported or stored and Valisure has not provided any additional data to suggest that benzoyl peroxide products form meaningful levels of benzene if stored in refrigerated or room temperature conditions.
In their report, most products tested by Valisure had almost no detectable benzene. These findings are a cause for optimism as they highlight that it is possible to safely use BPO-containing products with appropriate formulation and handling. However, there was substantial heterogeneity, with some products having potentially meaningful levels of benzene, which highlights the importance of improving the supply chain to ensure patient safety.
BPO manufacturers must be thoughtful about the production, distribution and storage of BPO-containing products to mitigate the potential risk of BPO products breaking down into benzene prior to use.
In addition, the potential exposures from BPO products need to be contextualized with respect to other exposures in our daily life. While we of course want to minimize benzene exposure as much as possible, it is not clear that these levels are a clinically meaningful incremental risk in the setting of an acne cream or wash. There is minimal absorption of benzene through the skin, and it is uncertain how much benzene goes into the air with routine use, particularly for washes which are not left on the skin.
Additionally, the “face model” experiment exploring the effects of UV radiation is challenging to interpret and likely not generalizable. Although little details are provided about how they decided which product to test, Valisure evaluated one of the products with the highest concentrations of benzene at baseline (second worst in their testing), which might not reflect typical products.
In addition, the limited volume of their testing conditions likely does not reflect outdoor environments, which are where UV light would typically be encountered. For those who are concerned, these theoretical issues could likely be avoided by using a BPO wash, rather than a leave-on product.
We also need more transparency and independent replication of Valisure’s results to evaluate whether these findings are generalizable and reproducible, particularly given potential conflicts of interest. More prospective studies of the effects of routine use of BPO on blood benzene levels and risk of cancer are also needed, including whether formulation or duration of use influence these outcomes.
Overall, BPO products should be stored at room temperature or refrigerated and discarded after a few months or if expired. I look forward to hearing from the FDA for its input on this important matter.
References:
Reynolds RV, et al. J Am Acad Dermatol. 2024;doi:10.1016/j.jaad.2023.12.017.
Sadr N, et al. J Am Acad Dermatol. 2024;doi:10.1016/j.jaad.2024.06.050.
Garate D, et al. J Am Acad Dermatol. 2024;doi:10.1016/j.jaad.2024.07.011.
Barbieri J, et al. J Am Acad Dermatol. 2024;doi: 10.1016/j.jaad.2024.05.093.
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