Your Antibacterial Soap Could Be Harming You

Illustration for article titled Your Antibacterial Soap Could Be Harming You

Every time you wash your hands using antibacterial soap you probably feel good because you're not spreading bugs. But check the bottle and you'll probably find the soap contains triclosan—a chemical that has just been shown to impair muscle function in humans.


Research published in the Proceedings of the National Academy of Sciences suggests that triclosan hinders human muscle contractions at the cellular level, as well as inhibiting muscle function in both fish and mice. Isaac Pessah, one of the researchers, told Smithsonian:

"Triclosan is found in virtually everyone's home and is pervasive in the environment. These findings provide strong evidence that the chemical is of concern to both human and environmental health."

The study investigated how triclosan affected human heart and skeletal muscle cells in the lab. They found that it disrupted communication between proteins which allow the muscles to function, in turn causing failure of both types of cells. They backed up those experiments with tests on fish and mice. The mice showed reductions in heart muscle function by as much as 25 percent, and a reduction of grip strength of 18 percent. The fish became less effective swimmers after exposure to triclosan.

So what's to do? There's no denying that the chemical has some negative effects on muscle function, and the researchers are genuinely concerned about the health risks it poses. Nipavan Chiamvimonvat, another of the researchers, explained to Smithsonian:

"The effects of triclosan on cardiac function were really dramatic. Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models."

Meanwhile, the FDA has declared that there's no evidence to suggest that using antibac soaps with triclosan offer any health benefits over just washing with conventional soap and water. So, for now at least, it might pay to ditch your fancy handwash. [PNAS via Smithsonian]

Image by SCA Svenska Cellulosa Aktiebolaget under Creative Commons license




In my career in ion channel function research, I'm rarely surprised when I find that a polycyclic hydrocarbon blocks a channel at high enough concentrations, though the 0.520 micromolar they cite for significant effects isn't necessarily what I'd call 'high' for some pharmacologic effects. If that's the low end of the concentration-response curve, the numbers that generally are used to describe how potent something (EC50) is are probably 'high'.

The concentration listed in the abstract is 12.5 mg/kg for effects in mice. The concentration in soap is about 0.2%. If you do the math you'd have to inject the amount of triclosan found in about 0.5 to 1.5 lbs of soap all at once into your abdomen to reproduce that effect in a humans. This is probably their minimum effective dose. I'd question whether you'd find that concentration in any living thing or even the environment.