It's a no-brainer, especially during cold and flu season: When you use the bathroom, you wash your hands afterward. You just got home after holding onto a subway pole for dear life. You wash your hands. You're about to eat a sandwich. You wash your hands. It's become second nature.
But an alarming new study published in Proceedings of the National Academy of Sciences says that washing your hands might be doing more harm than good if you're not paying attention to what kind of soap you use.
Triclosan, a common microbial found in antibacterial personal hygiene products like soap, toothpaste, shampoo, and cosmetics, has been found to cause liver fibrosis and cancer in mice. Mice exposed to triclosan for six months — the equivalent of 18 human years — were more susceptible to liver tumors, and their tumors were larger than those in mice who were not exposed to the chemical. And the molecular mechanisms by which the triclosan causes these conditions affects humans similarly.
"Triclosan's increasing detection in environmental samples and its increasingly broad use in consumer products may overcome its moderate benefit and present a very real risk of liver toxicity for people, as it does in mice, particularly when combined with other compounds with similar action," said lead author Robert H. Tukey in a UC San Diego press release.
Past studies have found traces of triclosan in 97% of breast milk samples from lactating women and in the urine of nearly 75% of people tested, according to a press release for the current study, which could make it the most commonly used consumer antibacterial.
But don't fret just yet: The mice in the study were eating and drinking the triclosan in their food and water at "super high concentrations" for six months, which isn't comparable to the amount used in hand or hair washing.
The study's co-author, Bruce D. Hammock, advocates banning triclosan in hygiene products such as liquid hand soaps, but concedes that triclosan levels in toothpaste is too minimal to be dangerous. Clearly, more research needs to be done to find out how the chemical could affect us in lower doses.
Until then, it's up to consumers to decide if using triclosan is worth the potential risk. For those who want to go triclosan-free, read a product's ingredient label before use, and stay away from antibacterial soaps, which apparently don't prevent illness any better than regular soaps anyway.
One thing's for sure: You should definitely keep washing your hands. No one likes a bacteria-packed handshake.