Is Antibacterial Soap Bad For You? (Part 1)

by David on February 25, 2013

It seems like everything is antibacterial these days, from soaps and lotions to mattress pads and pizza cutters, which really makes you wonder how the world got along before the discovery of Triclosan. Ah, Triclosan, the miracle-working active ingredient in antibacterial soaps, toothpastes, and a galaxy of other consumer products: this unassuming antibacterial compound has infiltrated nearly every aspect of our lives. In my posts for this week and the next I’ll be exploring the profound effects Triclosan has on human health, the environment, and antibiotic resistance, all to answer the (deceptively) simple question: is antibacterial soap bad for you? (The short answer is yes - but not for the reasons you might suspect!)

Bacteria are attacking our pizza? IS NOTHING SACRED


What is Triclosan, and why is it in Pizza cutters?

Triclosan was developed as a broad-spectrum antibiotic (that is, to kill a wide range of bacteria) and has been used in clinical settings since the late ‘60s to help prevent nosocomial (that is, hospital-borne) infections. The first commercial uses of Triclosan appeared during the ‘70s, when it gained popularity as a component of deodorants – no underarm bacteria meant no stinky armpits. In the last few decades, marketers have capitalized on the power of science as an advertising tool and vilified bacteria so successfully that – in addition to deodorants – you can now purchase thousands of products (including pizza cutters) brimming with bacteriocidal Triclosan.

“Out, damn’d spot! out, I say!” – Lady Macbeth, who never used Triclosan

On the importance of hand washing

You’re most likely to notice Triclosan as a component of antibacterial hand soap, and here at MTSG, we take hand washing very seriously. Unfortunately, there is very weak evidence to suggest that the general public is likely to benefit from the addition of Triclosan to hand soap. Although one literature review found antibacterial soaps to be slightly more effective than normal soaps, there is still the matter of a massive epidemiological study that found no significant practical difference between the two. Of course, what you use to wash your hands doesn’t really matter if you dry them off by wiping them off on your pants or using a dirty rag – there’s plenty of evidence that how you choose to dry your hands can enhance or negate the effects of washing them, rendering your choice of soap a moot point.

Heck, just wash your hands with the garden hose and dry ‘em off on a grizzly bear, it’s all the same.

Antibiotic resistance, Problems with

In addition to driving up the cost of hand soap, the inclusion of Triclosan into myriad consumer products appears to be increasing levels of antibiotic resistance in all kinds of bacterial species. It’s a fairly straightforward process: no matter how well you wash your hands, you’re never going to clean off all of the bacteria, and there will always be some that survive the deluge of soap, Triclosan, and water. Often, these bugs survive because they have mutations in their DNA that change some aspect of their biology that prevents the Triclosan from doing what it’s supposed to do. Sometimes, bacteria can exchange these mutated genes (when they confer resistance to antibacterial compounds, we call them “resistance genes”) with one another on little rings of DNA called plasmids. By trading these plasmids like baseball cards, different species of bacteria can pick up all kinds of resistance genes, making infections harder to treat and increasing the number of hospital-borne infections. Of particular concern is that one of the most popular mutations for Triclosan resistance also confers resistance to Isoniazid – an antibiotic used to treat tuberculosis.

They’re useless against TB now, but at least they’re raspberry-flavored!

Human toxicity?

For most of its life, Triclosan has been thought to pose little toxicological risk to humans at the concentrations at which it is normally encountered, but a slew of recent studies have called this safety into question. Researchers have found that Triclosan can potentially mess with sex hormonal activity and seems to exacerbate immune hypersensitivity disorders like allergies and asthma. One study even found that Triclosan could weaken cardiac and skeletal muscles! Granted, the doses involved in these studies are generally fairly high so these findings should be taken with a grain of salt. Even so, when you consider how much of this stuff we’re exposed to on a daily basis, and the fact that Triclosan is easily detected in blood, urine, and breast milk, you may start to wonder about the cumulative effects of all that exposure…

It was then that Anthony realized his mistake. He frolicked not in snow, but pure powdered Triclosan.

Taken together, all of this means that for the average person antibacterial soaps are probably not any more likely to improve their health outcome than washing with boring old regular soap. This is not to say that Triclosan doesn’t have a use, only that its proper use isn’t in consumer products.  When used judiciously, it’s tremendously effective at controlling the spread of microbial disease and nosocomial infections, but when used imprudently, Triclosan may ultimately cause more health problems than it solves.

Tune in next week for part two: Triclosan in the environment!

mike February 25, 2013 at 12:34 pm

Triclosan is very similar chemically to hexachlorophene which was severely restricted in the 1970′s due to its toxicity.

David February 25, 2013 at 11:25 pm

It’s also some what similar to BPA – they’re both bisphenolic compounds!

Travis February 25, 2013 at 12:58 pm

Mike, while I think we may agree that antibiotic soaps are bad, I feel like the term “chemically similar” is devoid of meaning. Even compounds that have only slight differences can have vastly different effects.

In that vein, consider that elemental sodium and elemental chlorine are generally toxic to humans, but together they make salt.

David February 25, 2013 at 11:32 pm

Thanks for the comment, Travis, and you are right to be skeptical of “chemical similarity,” but there are occasions when it scientists do make use of the idea. For example, in the practice of Risk Assessment, one may be required to predict the hazard posed by a compound for which there is very little exposure data available. In these circumstances, it is not uncommon to draw on data available from a STRUCTURALLY similar compound when attempting to predict the properties of an unknown entity.

Jocelyn February 25, 2013 at 12:59 pm

Agh! I was unaware that Triclosan is now violating pizza cutters as well! Avoiding this stuff is becoming a rather difficult proposition… Excellent post! :)

David February 25, 2013 at 11:33 pm

It is indeed! I’m glad you enjoyed the post! :)

Eve February 25, 2013 at 5:34 pm

Great post, very informative…but my favorite part is definitely the captions!

“It was then that Anthony realized his mistake…”

David February 25, 2013 at 11:33 pm

The captions are definitely the most enjoyable part of writing the posts :)

Robb February 26, 2013 at 2:06 pm

Well said. If only the drawbacks from anti-bacterial soap were better understood by the general public.

David March 1, 2013 at 2:07 pm

I’m glad you liked it! Thanks for the comment.

Doug February 27, 2013 at 5:41 pm

Referring to triclosan as an “antibiotic” pushes rather beyond the limits of the generally-accepted definition. In the linked “thousands” paper, the phrase “… to both triclosan and to antibiotics” appears. This language would be very unlikely if triclosan were generally considered an antibiotic.

Interesting that triclosan is derived from good ol’ carbolic acid, the first known disinfectant.

David March 1, 2013 at 2:20 pm

Good catch, Doug. You’re right, the terminology can get a bit sticky when translating from the extremely precise parlance of scientific writing to to a diction more suitable for non-scientists. While I agree that triclosan isn’t an antibiotic in the way that most people think about antibiotics – that is, a pill that you take when you’re sick – it by its mode of action and use an antibiotic. I think that the government document that I cited is accounting for this subtle difference in usage when it refers to triclosan separately from antibiotics – specifically, the types of antibiotics that a doctor would prescribe – because most readers would also make that distinction, even though many scientists wouldn’t.

Altogether, you raise an excellent point about the conventions of scientific communication and how they differ from the conventions of normal speech. Thanks for the comment!

Mrs. Stephen February 27, 2013 at 8:46 pm

Sorry, this is a test. #SPX9

Robert March 1, 2013 at 1:08 am

Just wanted to follow this series.

David March 1, 2013 at 2:08 pm

Stay tuned for part 2, coming Monday morning!

Virginia March 1, 2013 at 11:49 pm

This warning is appreciated. Your research and post will save money . When my gift bottle of antibacterial is depleted I shall abstain. Is the FDA looking into this?

David March 3, 2013 at 11:54 pm

Thanks, Virginia! Yes, the FDA is taking an interest (http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm205999.htm) but they haven’t released any updated evaluations yet, because there is still a lot of research to be done.

Angela March 3, 2013 at 7:31 pm

Great topic! I used to work as a carer and a chef, and in both places, people were obsessed with anti-bacterial stuff. I didn’t feel comfortable at all with the stuff, especially coming from a country where many people still clean with vinegar and other ‘old-fashioned’ means.
I may have mentioned this before as a comment, but it made me think again of a study we read about during food hygiene training, where one house was cleaned with drug-store bought anti-bacterial products, and the other house was cleaned with vinegar and baking soda. If I remember correctly, no difference was found in the amount of surviving bacteria. Don’t know about the difference in the type of bacteria, though…

David March 4, 2013 at 12:25 am

Hi Angela. I’m glad you enjoyed the post! I’m not sure which study you refer to, but I think that it might be this one? http://www.aciscience.org/docs/alternative_hard_surface_cleaners.pdf

In any case, you raise an excellent point about the efficacy of cleaning measures that don’t use powerful antibacterial agents – namely that normal soaps or vinegar are probably sufficient for everyday cleaning needs. In terms of the types of bacteria involved, much like normal soaps or vinegar, most industrial-strength anti-bacterial compounds aren’t more specific for bacteria that might harm humans than for benign or even helpful bacteria – they just kill them all.

Angela March 4, 2013 at 6:42 am

Yes, I think that’s the one! We were given a summary of it. Thanks for finding it!

Erin March 4, 2013 at 8:51 am

As a soap maker, I field many questions involving triclosan, antibacterial soaps, and ordinary soap’s germ fighting ability. The general public has been lead to believe that antibacterial products are better for, and even necessary in preventing and eliminating germs. While antibacterials certainly have their place, I don’t feel the average home should be mounting such a powerful offense against microbial invaders. It’s especially compelling that even after years of study, scientific evidence continues to support soap and water as simple, yet effective weapons in maintaining good health. No triclosan, hormone disruption, or river/lake pollution necessary!

David March 24, 2013 at 3:59 pm

That’s great! Thanks for the comment, Erin!

Jimmy April 30, 2013 at 1:42 pm

Ha, I just switched from regular soap to antibacterial soap. Im not obssesed with antibacterial products in my home so I’m not sure of how much exposure I’m getting to triclosan, but would having antibacterial soap to wash my hands and shower really pose a health risk for me?

David May 4, 2013 at 9:31 pm

Hi Jimmy, thanks for the question! The short answer is: No, it’s not necessarily the case that it will pose a health risk for you in the immediate term – although a few studies (as linked in the post) have suggested that low doses of triclosan products applied to the skin might (in chronic use scenarios) exacerbate allergies. (a lot more research needs to be done on the topic)

Important questions to consider are: What is the benefit of using antibacterial products containing triclosan? How do you need to use these products to attain this benefit? Are you able to use the products consistently and properly such that you can ensure that you will receive the benefit? While antibacterial soaps containing triclosan have demonstrated use in hospital settings, the soap formulations in these scenarios use a much higher concentration of triclosan than is present in most consumer products. Also, health care professionals in hospital settings are trained to laboriously wash and scrub their hands with the antibacterial soap – it’s not likely that most consumers will be as fastidious about their everyday hand-washing habits. (but then, maybe you are! if so, good for you!) Finally, a meta-analysis of hand DRYING literature reveals that it doesn’t really matter how good of a job you do washing your hands if you don’t dry them properly using a sanitary drying device. The hand towels that most people keep in their bathrooms and change out every week or so? Not at all sanitary.

Finally, while your personal use and exposure to antibacterial soaps containing triclosan may not necessarily lead to any problems for you, when millions of people use triclosan-containing products, much of that triclosan gets washed down the drain, and ends up contaminating the environment and (rather ominously) potentially our own water supply! (as indicated in my follow-up triclosan post: http://www.mindthesciencegap.org/2013/03/04/is-antibacterial-soap-bad-for-you-part-2/) There’s also that whole Antibiotic-resistant Tuberculosis thing that seems to be related to low dose triclosan exposures (low doses like those found commonly in consumer products).

In sum: the only FDA-approved indication for triclosan is as a toothpaste additive (it helps reduce bacterial loads in the mouth and also has anti-inflammatory properties), so it’s kind of strange that it’s showing up in soaps anyway… Personally, I blame the vilification of bacteria, which, as I describe in another post (http://www.mindthesciencegap.org/2013/03/11/what-are-probiotics-an-ode-to-the-microbiome/) are not all bad, and are actually quite important for our health!

Thanks for reading!

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