How do antibacterial agents in clothing work?

December 5, 2012 7:50 AM

I just bought some HEATTECH long undies from Uniqlo. They claim to have a "special antibacterial agent" in them to minimize odors. Lots of other products these days make similar claims. How does this work? Is it basically a pesticide embedded in the fabric? If so, why doesn't it wash out? What exactly would it be? Are there health concerns?
posted by HotToddy to clothing, beauty, & fashion (10 answers total)

I don't know what's in those clothes, specifically, but a lot of such clothing includes nano particles of silver. They do wash out over time, but slowly. There are general health concerns with nano particles (because they're so small that they can more readily do things like cross the blood-brain barrier and some nano carbon tubes act like asbestos), and there's a lot of research being done. I don't know of concerns specifically from nano silver for human health; I have heard concerns about the nano silver in waste water being a problem for ecological receptors.
posted by ldthomps at 7:55 AM on December 5, 2012 [5 favorites]

I have some yoga stuff made with something similar, called SilverLight or something, I think? From what I can tell (although it admittedly might be something weird with my body chemistry) it does fuckall except impart a weird/unpleasant odor to the fabric once you've sweated in it that lingers relentlessly unless you wash it on the hottest setting possible by your machine. I do not get this weird stink in all the other non-SilverLight items of clothing in which I sweat mightily.
posted by elizardbits at 8:27 AM on December 5, 2012

It's not necessarily silver or something toxic. Lanolin in wool has natural antibacterial properties, for example. There is also some research into attaching enzymes (lysozyme) that can lyse (basically explode) bacterial cells without harming human cells to fabrics, such as here. The use of enzymes in regular old products is not new either, proteases have been used in laundry detergent for decades to break down stains that have a lot of protein (i.e. blood).

I searched a bit and couldn't find what supposedly "antibacterial" technique Uniqlo uses for their Heattech line, other than the milk proteins that are supposed to trap heat. I wouldn't worry too much about it... I've been wearing heattech undershirts for years now and I am not dead yet! datapoint = 1.
posted by permiechickie at 8:32 AM on December 5, 2012

I think it's the rayon fibre. Bamboo fibres are now labelled as rayon, and bamboo is antibacterial.
posted by veids at 8:37 AM on December 5, 2012

Bamboo is not antibacterial. Source in a previous comment of mine. Rayon is not antibacterial unless it's been treated with something else; permiechickie is correct that it could be some benign enzyme.
posted by clavicle at 8:57 AM on December 5, 2012 [2 favorites]

In general, the anti-bacterial agent you might want to be concerned about is Triclosan. Its safety is under review but it's still found in a wide range of products.
posted by Dansaman at 10:13 AM on December 5, 2012 [1 favorite]

They might be referring to chitin.
posted by en forme de poire at 11:16 AM on December 5, 2012

Not endorsing that page or the claims made there, BTW, just linking it as an example of using chitin in clothing materials as a (potentially?) antimicrobial material.
posted by en forme de poire at 11:20 AM on December 5, 2012

If so, why doesn't it wash out?

I dunno whether it washes out or not, but my Uniqlo Heattech top has started smelling quite dreadfully after just a few hours of wear, even if I am freshly showered and deodoranted.
I bought it in October last year and wore it obsessively tho, so it did last a while.
posted by ClarissaWAM at 12:11 PM on December 5, 2012 [1 favorite]

There's no way to know the answers to your questions without knowing specifically what the "antibacterial agent" in their fabric is, and their website isn't telling us that. The only possible way to get better information would be to call or write the company and see if they will tell you. (heh -- good luck with that).

It seems that claims for antibacterial action are being made for lots of fabrics that are considered to have wicking properties superior to cotton, but which don't have any other special properties or ingredients. I've seen these claims for silk, linen, rayon, wool, polypropylene, and others. If that's the basis of the claim, I wouldn't be very impressed by it but I wouldn't have any concerns about using the fabric.

This opinion isn't based on any special expertise, but I've decided not to buy any textiles that claim to be "antibacterial" based on the use of silver or some whiz-bang new technology. Our skin has lots of beneficial bacteria that are there for important reasons -- if some new fabric really does have effective antibacterial properties, I'm not so sure I want to be wearing it next to my skin on a regular basis. If my clothes start to get smelly, washing and drying them seems to be sufficient, and safe, and a good idea anyway.
posted by Corvid at 12:40 PM on December 5, 2012