Dear EarthTalk: I heard about a supposed dangerous chemical called "triclosan" that is in many personal care and other consumer products. Can you enlighten?
—Carl Stoneman, Richland, WA
Triclosan is a synthetic chemical compound added to many personal and household care products to inhibit illness by preventing bacterial infection. It works by breaking down the biochemical pathways that bacteria use to keep their cell walls intact, and as such kills potentially harmful germs if used in strong enough formulations. First developed as a surgical scrub back in 1972, triclosan is now used in upwards of 700 different consumer-oriented products, many of which people use more than once a day. They include hand soaps, deodorants, toothpastes, kids" toys, yoga mats and, of course, hand sanitizers.
Whether triclosan is actually as effective as advertised, especially in the small doses found in consumer products, is a topic of much debate. Manufacturers insist that the product helps reduce infections. But researchers from the University of Michigan’s School of Public Health found, after surveying 27 different studies conducted between 1980 and 2006 on the effectiveness of antibacterial soaps, that washing hands with products containing triclosan was no more effective in preventing infectious illness—and did not remove any more bacteria—than plain soaps. The analysis, "Consumer Antibacterial Soaps: Effective or Just Risky?" was published in 2007 in the peer-reviewed journal, Clinical Infectious Diseases. According to lead researcher Allison Aiello, triclosan—because of the way it reacts in living cells—may cause some bacteria exposed to it to become resistant to amoxicillin and other commonly used antibacterial drugs, but she adds that more research is needed to bear out this hypothesis.