I have problems with limbs going to sleep. I think it is all caused by the poor blood circulation or as my Dr. told me that I had low blood volume so that I just don't have enough to have good circulation. I drink lots of water, walk 2 miles most everyday and also take magnesium. Like you, I have recently found that I have to take even more to get the same results, but I think that for me it is because of the defoliant that they are spraying on the cotton fields where I live-everyone has problems during this time, not just us sick people! You might be getting exposed to something that is causing you to need even more (mg helps with detox pathway)

Also, magnesium helps with the twitching as that is a mild muscle spasm.