Concerns have swirled around the popular antibacterial chemical triclosan for years, linking the chemical to health implications such as impaired thyroid function and liver toxicity. And a new study adds to these concerns with the finding that triclosan may also impair muscle function.

The new study, led by researchers at the University of California Davis, concluded that triclosan may hinder muscle function in both animals and humans. The study, published recently in the Proceedings of the National Academy of Sciences, looked at the effects of triclosan in humans and found that it impairs human muscle contractions at the cellular level. Exposure to triclosan actually disrupted the cell communication that is necessary for muscles to function properly. This caused failure in both the heart and skeletal muscle cells.

Researchers also evaluated triclosan's effect on fish and mice and found that it inhibited normal muscle functioning in both. In the mice, triclosan exposure reduced proper heart function by as much as 25 percent while grip strength was reduced by as much as 18 percent. For the fish, minnows were exposed to concentrations of triclosan similar to those found in the wild for seven days. After exposure, the minnows were significantly worse swimmers than those who were not exposed to the chemical and were also less efficient in swimming tests that evaluated their proficiency at evading a predator.

Like it or not, triclosan is ubiquitous in the marketplace. According to the Environmental Working Group's Guide to Triclosan, more than 140 household products — everything from antibacterial soaps to deodorant to toothpaste to vacuum bags — contain triclosan. The guide also notes that wastewater treatment does not remove all of the chemical, so triclosan ends up in lakes, rivers and water sources, making it ubiquitous in the environment as well.

The study's authors argue that the pervasiveness of triclosan adds to the concern about its health implications. "These findings provide strong evidence that the chemical is of concern to both human and environmental health," noted the study's lead author, Isaac Pessah.

Want to limit your family's exposure to triclosan? MNN's home blogger Matt Hickman has some great tips in his post on getting triclosan out of your home.

More bad news about triclosan
New study links triclosan to impaired muscle function in tests on humans and animals.