Disinfecting wipes. Antibacterial sprays. The cleaners we reach for without a second thought are part of our daily routines at home, at school, and at work. But new research is showing that these familiar products may come with hidden risks.
Libin Xu, associate professor of medicinal chemistry at the University of Washington School of Pharmacy, studies quaternary ammonium compounds—or “QACs”—a class of chemicals found in many disinfectants, particularly benzalkonium chlorides. His team has found that exposure to QACs is nearly universal.
“Almost every human sample measured so far has certain amounts of this compound, from very low to, occasionally, pretty high amounts,” Xu says. Traces have been detected in human blood, urine, feces, and breast milk, and even in the house dust—underscoring how easily these chemicals become part of our everyday lives.
Why does this matter? Recent studies by the Xu Lab found that QACs could affect cholesterol biosynthesis and lipid metabolism in neonatal mouse brains during the critical embryonic development period and disrupt gut microbiome homeostasis and metabolism in a mouse exposure model.1, 2 These compounds can be taken up via oral exposure or inhalation. The Xu Lab further found that QACs can be metabolized by human cytochrome P450 enzymes,3, 4 but they can accumulate in certain organs, such as the kidney and lung. Collaboration between the Xu Lab and Joanne Wang’s Lab found that while some QACs can be transported by transporters, they are not excreted efficiently,5 which may contribute to their accumulation in certain organs, such as the kidney. Furthermore, evidence suggests that QACs are preferentially excreted into the GI tract, hence the impact on the gut microbiome, which has been found to have numerous beneficial effects on human health. The figure below illustrates the fate of QACs in the human body based on the current knowledge.
While abundant studies in animals have demonstrated the potential detrimental effects of QACs, more research is needed to understand their effects on people. The Xu Lab’s ongoing projects funded by the National Institutes of Health (R01ES031927 and R01ES035021) aim to address the mechanistic gaps of QAC toxicity and their impact on human health.
“We’re not saying to stop cleaning,” Xu notes. “But it’s worth being aware of the potential health impact and choosing safer alternatives when you can.”
Simple changes—like checking labels, improving ventilation while cleaning, or using soap and water—can reduce your exposure without sacrificing safety. Because when it comes to protecting our health, knowledge is one of the most powerful tools we have.
1. Herron, J. M.; Hines, K. M.; Tomita, H.; Seguin, R. P.; Cui, J. Y.; Xu, L., Multiomics investigation reveals benzalkonium chloride disinfectants alter sterol and lipid homeostasis in the mouse neonatal brain. Toxicol. Sci. 2019, 171, 32-45.
2. Lopez, V. A.; Lim, J. L.; Seguin, R. P.; Dempsey, J. L.; Kunzman, G.; Cui, J. Y.; Xu, L., Oral Exposure to Benzalkonium Chlorides in Male and Female Mice Reveals Alteration of the Gut Microbiome and Bile Acid Profile. Tox. Sci. 2024, 202 (2), 265–277.
3. Seguin, R. P.; Herron, J. M.; Lopez, V.; Dempsey, J. L.; Xu, L., Metabolism of Benzalkonium Chlorides by Human Hepatic Cytochromes P450. Chem. Res. Toxicol. 2019, 32 (12), 2466-2478.
4. Nguyen, R.; Seguin, R. P.; Ross, D. H.; Chen, P.; Richardson, S.; Liem, J.; Lin, Y. S.; Xu, L., Development and Application of a Multidimensional Database for the Detection of Quaternary Ammonium Compounds and Their Phase I Hepatic Metabolites in Humans. Environ Sci Technol 2024, 58 (14), 6236-6249.
5. Vieira, L. S.; Seguin, R. P.; Xu, L.; Wang, J., Interaction and Transport of Benzalkonium Chlorides by the Organic Cation and Multidrug and Toxin Extrusion Transporters. Drug Metab Dispos 2024, 52 (4), 312-321.