There's no evidence antibacterial soap is more effective

And that, says the U.S. Food and Drug Administration, is a problem. Antibacterial soap products contain potentially harmful ingredients you won't find in regular soaps – and the risks of those ingredients could outweigh antibacterial products' unproven benefits.

Top photo by siljegarshol via Flickr.

The FDA called the safety of over-the-counter antibacterial soap products into question yesterday, with the release of this "Consumer Update" statement. The agency's line of reasoning is simple: Many of us buy antibacterial soaps with the expectation that they are more effective at killing germs, and therefore reduce our likelihood of contracting illnesses or spreading them to others. But antibacterial soaps also contain ingredients like triclosan and triclocarban, "which may carry unnecessary risks given that their benefits are unproven":

...there currently is no evidence that over-the-counter (OTC) antibacterial soap products are any more effective at preventing illness than washing with plain soap and water, says Colleen Rogers, Ph.D., a lead microbiologist at FDA.

"New data suggest that the risks associated with long-term, daily use of antibacterial soaps may outweigh the benefits," Rogers says. There are indications that certain ingredients in these soaps [including triclosan and triclocarban] may contribute to bacterial resistance to antibiotics, and may have unanticipated hormonal effects that are of concern to FDA.

In light of these data, the agency issued a proposed rule on Dec. 16, 2013 that would require manufacturers to provide more substantial data to demonstrate the safety and effectiveness of antibacterial soaps. The proposed rule covers only those consumer antibacterial soaps and body washes that are used with water. It does not apply to hand sanitizers, hand wipes or antibacterial soaps that are used in health care settings such as hospitals.

Manufacturers will be required to demonstrate that their substances are safe and effective, or face removing them from their products altogether.

Triclosan and Triclocarban

Findings from studies on ingredients like triclosan and triclocarban are something of a mixed bag. A preliminary study on the latter found it to augment testosterone activity in rats, albeit only following exposure to very high concentrations of the substance. Triclosan, on the other hand, has been singled out as an endocrine disruptor in several studies, and is hypothesized to interfere with thyroid signaling by mimicking the natural hormone and blocking its receptor sites. Last year,scientists published research linking triclosan to muscle impairment. It's also used in agricultural applications as a pesticide, which obviously rubs some people the wrong way. One of the few human trials involving triclosan found the agent hand no discernible effect on the concentrations of thyroid hormone in its subjects – however the test subjects in this study were all adults; as the FDA notes on page 76454 of a rule published today in the Federal Register:

Because consumer antiseptic washes are chronic use products and are used by sensitive populations such as children and pregnant women, evaluation of the potential for chronic toxicity and effects on reproduction and development should be included in the safety assessment... The potential of hormonally active antiseptic active ingredients to cause developmental or reproductive effects raises particular concerns for the safe use of these ingredients on children.

Speaking on triclosan, specifically, the FDA said it would team up with the Environmental Protection Agency in order to "review [its] effects from two different perspectives":

EPA regulates the use of triclosan as a pesticide, and is in the process of updating its assessment of the effects of triclosan when it is used in pesticides. FDA's focus is on the effects of triclosan when it is used by consumers on a regular basis in hand soaps and body washes. By sharing information, the two agencies will be better able to measure the exposure and effects of triclosan and how these differing uses of triclosan may affect human health.

Antibiotic Resistance

In the rule published today in the Federal Register, the FDA also calls attention to the fact that antibiotic products could be contributing to antibiotic resistance in microbial organisms. From the middle column of page 76454 of the rule (my emphasis):

Given the increasing evidence about the magnitude of the antibiotic resistance problem and the speed with which new antibiotic resistant organisms are emerging, it is important to assess this potential consequence of consumer antiseptic use.

The joint Committee recommended that FDA work with industry to establish surveillance mechanisms to address antiseptic and antibiotic resistance. At the October 2005 [Nonprescription Drugs Advisory Committee] meeting on antiseptics for consumer use, however, some NDAC members expressed concern about the societal consequences of the pervasive use of consumer antiseptic wash products, including the potential for antiseptic use to lead to changes in bacterial susceptibilities to clinically important antibiotics.

For more info, see the the FDA's full statement and the agency's full rule in the Federal Register.