Soap companies don't seem to think soap really gets people, or dishes, clean. About half the liquid soaps they sell in the United States are fortified with bacteria-killing chemicals.
Soap companies say an abundance of evidence shows that these products kill more germs than ordinary soap does. That's debatable, but it's not even the point. There's no benefit to killing germs unless the result is less illness. And there is no good evidence that antimicrobials protect people's health. And increasing evidence suggests they may help make germs more powerful.
Over the next year, soapmakers will have to either prove their germ-killing products are safe and effective or else take them off the market, the Food and Drug Administration has ruled. This mandate comes decades later than it should have; the FDA first drafted the order 35 years ago. It took a lawsuit from the Natural Resources Defense Council to force the agency's hand. Still, it is the right move.
The research so far suggests that soapmakers have an uphill climb to meet the FDA's demand. In a 2007 survey of multiple studies, not a single one of four trials showed a significant reduction in illness symptoms in households that used antimicrobial soap.
The survey also cast doubt on the idea that these products are superior germ killers. In five of nine studies, those who washed with an antimicrobial had significantly fewer bacteria on their hands. Yet in four of those trials, the biocide used was two to 10 times as concentrated as is typical in consumer soaps. In the fifth study, the reduction in bacteria was achieved only when volunteers washed their hands for 30 seconds 18 times a day.
To continue selling antimicrobials, the soap industry will also have to address new indications that some of these products may be harmful.
The most common agent in antimicrobial soaps is triclosan, a chemical that is structurally similar to thyroid hormones and has been shown in animal studies to alter hormone regulation. Other studies suggest that triclosan and the related agent triclocarban may contribute to antibiotic resistance in bacteria that cause disease in humans. More than 2 million people fall ill with antibiotic-resistant infections in the U.S. each year, and at least 23,000 die. Research has shown that triclosan can enter the food chain through wastewater. It's become so ubiquitous, 72 percent of Americans have triclosan residue in their urine.
These are hardly risks worth taking, absent strong evidence that antibacterial soaps make people healthier. If soap companies can't prove their products work, the FDA should ban them.