The silver ion inhibits bacterial growth on the skin. I wear the socks almost year-round if I'm wearing pants as they actually help REDUCE FOOT ODOR, and are the MOST comfortable socks I've ever worn. If I could find them in a footie sock, I'd wear those the rest of the time. The theory only works when you start w/ good hygiene, and build from there. I wear the base layers and socks, I'm not sure that any of the OTHER stuff would really be that effective as it's not AGAINST THE SKIN, but the base layers and socks ARE as good as advertised in my opinion.