Researchers at Brown University's School of Public Health found that children exposed to higher levels of triclosan may be more likely to develop eczema and allergy symptoms.
PROVIDENCE, R.I. [Brown University] - Triclosan is an antimicrobial chemical that was for decades added to everyday items like soap, toothpaste, cosmetics and even kitchen utensils and athletic wear, until concerns about potential health risks led manufacturers to phase it out of some products.
New research suggests there may be even more reason for concern.
A study led by scientists at Brown University and the University of Massachusetts Amherst found that children with higher levels of triclosan in their bodies were more likely to have allergy-related health issues, with young boys appearing most affected.
Published in Environmental Health Perspectives, the study followed 347 mothers and their children from pregnancy through the kids' 12th birthdays. As part of the Cincinnati-based Health Outcomes and Measures of the Environment Study, researchers analyzed urine samples collected up to 10 times over that period to assess triclosan exposure in children.
They found that children with higher levels of the chemical were more likely to develop allergic conditions like eczema and hay fever, a common allergy that causes sneezing, congestion and itchy eyes.
"The research showed a clear connection between this chemical and the allergic conditions we looked at," said study senior author Joseph Braun, a professor of epidemiology and director of the Center for Climate, Environment and Health at Brown University's School of Public Health. "What that all means is antimicrobial chemical exposure during susceptible periods of life, childhood in this case, might increase the risk of allergic disease."
The study found that children with twice the level of triclosan in their urine were 23% more likely to report eczema symptoms. This risk increased to nearly 40% by the time they were 8 to 12 years old. Similarly, children with twice the level of triclosan were 12% more likely to have symptoms of hay fever. Boys whose mothers had higher levels of triclosan during pregnancy were more likely than girls to show allergy symptoms.
The same reasons that make triclosan a health concern are in part what made it popular, said Hannah Laue, lead author of the study and an assistant epidemiology professor at UMass Amherst.
"Triclosan is effective at killing many bacteria, fungi and viruses," Laue said. "While that's useful for extending product shelf life or reducing odors in athletic wear, it can be harmful to humans. Our bodies rely on beneficial microbes to aid digestion and protect against pathogens. Exposure to triclosan may disrupt that healthy balance, leaving us more vulnerable to disease."
Laue added that triclosan can also interfere with hormonal systems.
"Some chemicals, including triclosan, can mimic or block hormones, potentially throwing essential systems into overdrive or shutting them down," she said. "Triclosan has also been linked to reduced thyroid hormone levels, which are critical for healthy growth and development."
A persistent antimicrobial
The U.S. Food and Drug Administration banned triclosan from over-the-counter hand soaps in 2016. Since then, many companies have voluntarily removed it from toothpaste and other products. Yet the chemical is still found in some consumer goods, including antimicrobial cutting boards, personal care items and clothing. Manufacturers are not required to list triclosan on product labels.
The new study is part of an effort by Braun's team to understand how antimicrobial chemicals affect children's health. Working with Laue and others, the group has focused on the health effects of triclosan for the last three years, and they plan to track the young study participants into adulthood. The researchers are especially interested in how triclosan might disrupt the gut microbiome, which helps regulate immune responses, and what that means for adolescent and long-term health outcomes.
Braun and Laue hope this body of research will encourage both consumers and manufacturers to make safer choices.
"People can reduce their triclosan exposure by doing what they can to avoid products that contain it," Braun said. "We also hope that this will prompt companies to consider using safer antimicrobial chemicals or avoiding them altogether in their products."
The study was supported by the National Institute of Environmental Health Sciences and the National Center for Advancing Translational Sciences. Additional Brown University authors included Elvira Fleury, who earned a master of public health from Brown in 2024 and is now a doctoral student at Harvard University.
