Natalie, it works for me just that way. Except I have to take twice what you do. If anyone tries it at 400 mg and it doesn't help enough, try twice as much. Some of us seem to use up magnesium at an unusual rate. Of course there's always the danger of diarrhea, and this is made less troublesome by using any form of mag other than citrate. I use Oxide,
and have used Taurate, Asparotate, and several others in combinations. My neuro said to try anything that does not cause diarrhea. If I get diarrhea I eat blackberries. That works so well that I must be careful not to go too far the other way. Feel like a test tube. I AM a test tube.