CrossFit in Stink-Free clothing and the sweaty athlete

Silver nanoparticle anti-microbial shirt
CrossFit in antimicrobial shirt by Lulu Lemon.  Research at UNTHSC.

Silver nanoparticles are used to create stink-free athletic clothing.    i.e. Clothing with anti-microbial properties.  Silver has low toxicity for people, but is able to kill bacteria.  How it kills bacteria is not completely understood, but it is believed to cause oxidative stress.  Oxidative stress is harmful for us as well, but bacteria can be killed at lower levels.  Still, oxidative stress is not good.  That’s why anti-oxidants are protective against cancer and cell damage.  

So, is it a good idea to put silver nanoparticles in clothes? No one knows the answer to this question.  But there are a few concerns. 

Do Silver nanoparticles come off the fabrics in which they are embedded? Apparently they do, but different fabrics lose nanoparticles at different rates, at least during the wash cycle.


Can silver nanoparticles be absorbed through people’s skin?  Silver nanoparticles are being used as a topical anti-biotic in burn patients.  Infection is a major, major factor in recovery (and mortality) for burn patients.  However, they may not have skin.  So this is probably not that relevant a point.  


How long do silver nanoparticles stay in a person once they get there?  This is an important question.  If they stay around a long time, they can do damage for a long time.  If they leave quickly they would be less dangerous.  Same thing goes for a lot of other substances.  The answer to this question appears to be unknown.


Are there any known health effects if silver nanoparticles are absorbed? Silver nanoparticles appear to have harmful effects on some human (and animal) cells.  (Comparative in vitro cytotoxicity study of silver nanoparticle on two mammalian cell lines)  While its been demonstrated that the particles can harm cells, tissues or organs we don’t know how much would be needed to cause harm to people when looking at them as a single unit.  The amount of silver nano-particles absorbed from clothing may not be high enough to matter.  Its an unanswered question.  One question that might be easy to answer is “how badly do you smell?”  Ask under different conditions.  Normal day.  After workout.  After workout and not having showered for 12 hours.  Not having bathed for a week.  Not having bathed for a month or more.  Young children will usually give a pretty frank answer.  

 References 

Lim DH, Jang J, Kim S, Kang T, Lee K, & Choi IH (2012).. Biomaterials, 33 (18), 4690-9 PMID:22459196.  Silver nanoparticles appear to have harmful effects on some human (and animal) cells.  (Comparative in vitro cytotoxicity study of silver nanoparticle on two mammalian cell lines).

Brandt O, Mildner M, Egger AE, Groessl M, Rix U, Posch M, Keppler BK, Strupp C, Mueller B, & Stingl G (2012). Nanoscalic silver possesses broad-spectrum antimicrobial activities and exhibits fewer toxicological side effects than silver sulfadiazine. Nanomedicine : nanotechnology, biology, and medicine, 8 (4), 478-88 PMID: 21839058

Benn TM, & Westerhoff P (2008). Nanoparticle silver released into water from commercially available sock fabrics. Environmental science & technology, 42 (11), 4133-9 PMID: 18589977

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