After lots of googling, I initially bought this for a friend who does heavy labor in the sun and would sometimes get home and just sit in his car because he was in such pain from muscle cramps. He used it for a couple months and he told me he was only cramping up rarely, and not nearly as severe. Then my brother mentioned that his feet were cramping, and I knew that he also does not hydrate properly (and depletes his electrolytes) so I got some for him, as well. When we took a family vacation in Florida, we were all putting this in our water the whole week. I was able to tolerate the heat so much better, and my brother's feet weren't cramping up anymore. Even if it's a placebo effect (though I don't think it is), it's absolutely worth the few cents a day to add this to your water! It provides a lot more than electrolyte drinks you pick up at the convenience store, what with the magnesium and potassium content. I even read somewhere that some people successfully use this to ease their hangover misery - don't ask me where, because I don't remember.
Rating: [5 of 5 Stars!]