memento’s suggestion to use magnesium sulfate as a magnesium supplement has worked out fine. I started taking it a couple of weeks ago after running out of magnesium oxide tablets. I apparently tolerate magnesium supplements well; as with the oxide, I have had no noticeable reaction to the sulfate.
The oxide was 500mg tablets. I cut them in half and spread the daily dose. I’m not sure how much sulfate I’m taking; it’s in coarse crystals like beach sand, and I just loaded up a bag full of leftover “0#” size capsules I had left over from disassembling some supplements to get at the contents. I just scooped them full from a bowl of magnesium sulfate and pushed the caps on, so I don’t know the weight of the dose. I have a precision laboratory scale out in the shop, but round tuits have been short lately.
Normal capsules have a compressed fill. I have a loading device for #3 capsules, which are much smaller than #0s. I’ll weigh a compressed load in a #3 as well, since that’s the size I’ll be using after I run out of the #0s. Each capsule size has to have its own loader tool.
Just in case you’re wondering, the smaller capsules generally cost more than the large ones. I suspect it’s because the large ones seem to be the most popular, and there are economies of scale at work.