FDA Calls for More Data on Antibacterial Soap Benefits

by Shannon Trepka

If you’re in the soap business, you might occasionally catch yourself geeking out over things that most people wouldn’t concern themselves with.  A discussion on the merits of antibacterial ingredients in personal care products is something that soap makers and ordinary people alike should be concerned with.

The main focus here is on the ingredient Triclosan, an antibacterial agent found in everything from toothpaste to toys, and in most liquid soaps labeled as “antibacterial”.  “Antibacterial” sounds like a good thing, but the FDA raises the possibility that the costs may outweigh the benefits, and with such widespread proliferation of triclosan (and triclocarban, a related ingredient often found in antibacterial bar soaps), the agency has asked for additional study of this ingredient, effectively asking companies producing antibacterial products to prove their efficacy and safety.  The problem is a lack of compelling evidence either way.  While some studies show clear benefits, others raise possible environmental and health concerns.

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What’s Good About Triclosan?

Triclosan is a broad-spectrum antimicrobial agent, meaning that it is effective against a wide range of microbes.  It works by disrupting cell membranes in bacteria, but apparently not in humans.  Cell membranes are essential to life, allowing oxygen and nutrients to enter, and allowing wastes to exit.  
Troclosan’s potency means that it can be used in fairly small concentrations, commonly between 0.1% and 0.45% weight/volume.  The FDA specifically recognizes its efficacy as an ingredient in toothpaste in preventing gingivitis.  Studies have shown that soaps containing triclosan significantly reduce the amount of bacteria on hands compared to plain soap, as well as the transfer of bacteria from hands to other objects after washing.  However, in the grand tradition of some scientific studies conflicting others, a University of Michigan study showed consumer-grade antibacterial soaps to be no more effective than plain soap and water in preventing illness.

What’s Bad About Triclosan

Biological and environmental concerns abound.  Much like antibiotic resistance, there is worry about bacteria growing resistant to triclosan.  Though certain studies have shown no significant development of such resistance in the short term, long-term adaptation of bacteria is still a concern, especially since traces of triclosan are left behind, unlike substances like ethyl alcohol that evaporate quickly and completely.

The environmental impact is also of concern, though again, results appear to be a mixed bag.  Significant amounts of chemicals like triclosan seem to survive wastewater treatment, and chemicals created by the breakdown of triclosan appear to remain in the environment for some time.  The chemicals of concern are dioxins and chloroform, both potentially carcinogens.  The amount of chloroform produced seems to be relatively small, less than is ordinarily found in chlorinated drinking water.  The dioxins produced do not appear to be of the type that is dangerous to birds, mammals, and fish.  However, triclosan negatively impacts the ability of diatom algae to accomplish photosynthesis, which is potentially bad for those of us that breathe oxygen.

The negative impact on the health of humans is in question.  Some studies show that it can be absorbed into the bloodstream, and may cause an increase in susceptibility to allergies in humans.  However, the EPA does not appear consider triclosan to be a serious health threat to humans based on our everyday exposure.  Studies involving animals have shown endocrine disruption in bullfrogs and impairment of muscle function in mice.  Despite these results, the FDA states directly that triclosan is not known to be dangerous to humans, and that negative impacts shown in animals do not necessary mean that such results can be replicated in humans.

What Conclusions Can We Draw?

Well, if you were thinking that the blog of a small artisanal soap maker was going to succeed where the FDA has so far failed, you were sadly mistaken.  The information we have isn’t better than theirs.  The unfortunate answer at this time is that there doesn’t appear to be a clear answer.

We’re inclined to believe that for everyday handwashing, ordinary soap and water will do.  In an interesting review of available studies on the efficacy and impact of triclosan, Tufts university researchers reached a similar conclusion.  Although they acknowledged a need for further research, they concluded there is cause for the FDA to review the situation, and that “Soaps containing triclosan at concentrations used in the community setting (0.2% or 0.3% wt/vol) were generally no more efficacious than plain soap at preventing infectious illness symptoms and reducing bacterial levels on the hands.”  Read more about the Tufts study here (pdf).