I have tried Prokarin, and it didnt do much for me personally. However, other swear by it. I think I read somewhere once that it has a tendency to help those that are heat sensitive, more.
It is pretty expensive, but if it works for you, its pretty cheap.
You can read more at links off this web site: http://www.healthwatcher.net/Quackerywatch/MS/
Even though its a "Quakery watch" web site, it has some good links to both sides of the argument.