Silver nanoparticles are added to all sorts of products from toys to textiles for their antimicrobial properties. (Bacteria cause the stink in your clothes; antimicrobial agents kill it.) While fixed nanostructured materials, like those found in microchip electronics, are believed to be benign, detachable nanoparticles like those found in some cosmetics and textiles are linked to adverse health effects. Sweat can dislodge nanoparticles in your workout clothes, so they fall into the potentially toxic site category, which leads to your question: Can you get a harmful dose of silver nanoparticles from your workout clothes? Unfortunately, its impossible to give you a straightforward answer, as researchers are still figuring out what constitutes a harmful dose. How youre exposed to the nanoparticles also matters, however. In that case, a Swiss study suggests that exposure to silver nanoparticles through workout clothes may warrant less concern than exposure through other products applied directly to the skin, like hand creams, or products that are taken orally, as oral absorption of silver nanoparticles is believed to be much more efficient than absorption through the skin. Also, the Swiss researchers assumed in their study that all of the silver nanoparticles released into sweat would be deposited on the skin. In real-life conditions, thats probably not true.