Washing hands with some antibacterial soap (Photo: Laura Holder via Flickr/Creative Commons)

Scientists in Colorado and California say in a study recently published online by the Proceedings of the National Academy of Sciences that they have found that a chemical used in some antibacterial soaps and similar products can obstruct muscle contractions.

They say that at a cellular level, the chemical can slow a fish’s swimming abilities and it reduces muscular strength in mice.

The chemical, called triclosan is an antimicrobial agent and its uses in the U.S. are regulated by both the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA).  Triclosan can be found in products such as soaps, deodorants, mouthwashes, toothpaste, bedding, clothes, carpets, toys and trash bags.

It should be noted that most hand sanitizers however use alcohol and do not contain triclosan.

According to researchers, a 1998 estimate by the EPA found more than 454 metric tons of triclosan is produced each year in the U.S.  The chemical was found in human urine, blood and breast milk. It was also found in various waterways and marine life including algae, fish and dolphins.

To assess the effects of triclosan on muscle activity, the scientists performed several experiments on mice and fish. They used doses of the chemical similar to what people and animals could be exposed to during everyday life.

“The effects of triclosan on cardiac function were really dramatic,” said study co-author Nipavan Chiamvimonvat, MD. “Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models.”

Dr. Chiamvimonvat cautioned that taking the results of their experiments with animal models to humans would be a large step and that further study is needed.  But researchers said the fact that the effects of the chemical were so striking in their experiments, provides strong evidence that triclosan could have effects on animal and human health at current levels of exposure.

Other experts are said to have also expressed concern that the overuse of antibacterial products could lead to the development of resistant bacterial strains.

The U.S. Food and Drug Administration said that although triclosan is not currently known to be hazardous to humans, they’re continuing to review it because of several scientific studies that have come out since the product was last reviewed.

“Triclosan can be useful in some instances,” noted Bruce Hammock, the study’s co-author, “however it has become a ubiquitous ‘value-added’ marketing factor that actually could be more harmful than helpful. At the very least, our findings call for a dramatic reduction in its use.”