If you're an antibacterial-soap junkie, it might be time to cut back. A three-part study suggests triclosan, a common chemical found in such products, slows muscle function in both human and animals. A paper published yesterday outlines the experiments: Scientists exposed human heart and skeletal muscle cells to levels of triclosan on par with what we typically encounter on a daily basis. An electrical stimulus was then applied to force the cells to contract—which should have happened immediately. But triclosan interfered with the proteins that enable this muscle function, leading to what Smithsonian Magazine describes as "failure." And that could spell trouble for people who have heart problems.
The study also turned to animals, and found that the grip strength in mice sank up to 18% after being exposed to one dose of triclosan; minnows who spent a week being exposed to the chemical couldn't swim as well. It's not just in soap, either. The ingredient is used in everything from toothpaste to bedding to cooking utensils. As the study's co-author explains, it "has become a ubiquitous 'value added' marketing factor that actually could be more harmful than helpful." Smithsonian notes that the FDA says that regular soap and water are equally as effective as antibacterial soaps containing triclosan; the FDA is currently reviewing the chemical. (Read more soap stories.)