Magnesium works for me for those awful leg cramps at night! I take two tablets a day of "Doctor's Best High Absorption 100% Chelated Magnesium," though I suspect there are other effective brands as well. I tried cutting back to one tablet per day, but that didn't work, so I'm back to two. The directions say that one can even take 2 tablets twice daily, so that might be required for some people to get the relief they need.