According to a new study by University of California researchers published in the Proceedings of the National Academy of Sciences , the active chemical in most antibacterial soaps, triclosan, which gives most antibacterial soaps and hygiene products their antibacterial properties causes liver fibrosis and promotes cancerous liver tumors.
"Although animal studies require higher chemical concentrations than predicted for human exposure, this study demonstrates that [triclosan] acts as a ... tumor promoter and that the mechanism of [triclosan]-induced mouse liver pathology may be relevant to humans," the study concludes.
Developed for use in hospitals in the 1970s, triclosan has become nearly ubiquitous, a popular additive in soaps, shampoos, toothpastes, mouthwash, cleaning supplies, and even kitchen tools and children's toys. But in the last decade, some studies have questioned its effectiveness (one 2007 study found triclosan antibacterial soap is no more effective at killing bacteria than regular soap) while others have raised alarms about triclosan seeping into tap water and mothers' breast milk. It's been found to harm waterborne life, and interfere with the normal functioning of the endocrine system, the thyroid, and testosterone. Because of all the questions about the value of the triclosan soaps, the FDA has given manufacturers until next year to prove they do more good than harm. Until then, the researchers suggest washing thoroughly for 20 seconds or more with plain old soap and water.
"We don't see a little bit of tumors," study author Robert Tukey tells ABC News about his findings on soaps containing triclosan. "We see very full blown tumorigenesis. It's on the extreme end of a tumor promoter and it does it very rapidly."