Magnesium deficiency does seem to be the culprit. However, for me I am up to about 5g of magnesium glycinate per day and the spasm are still occurring (however they're not as severe). I can also notice a difference about 20 min after oral supplementation, but it seems to only suppress the symptoms for 1-2 hours before I have to take more Mg. At high doses it does cause diarrhea and I've recently been trying transdermal supplementation (which seems to be helping as well). I'm also looking into IM shots of magnesium, but need a doctor script.

Does anyone know how long these symptoms last after stopping the cycle while continuing Mg supplementation?