Here is a good monograph on magnesium.

http://lpi.oregonstate.edu/infocente...als/magnesium/

About 70% of people are low in this mineral intake, because of poor eating habits in US.

Your goal for dosing should be 50% of the RDA. The RDA is in elemental form, not total weight.

Your label should explain how much elemental is in your product.

For SlowMag it is about 64mg/tablet. Taking 2 a day of these, gives 120mg and your RDA is about 350mg. So no you cannot harm yourself on this low dose.

Not all of any mineral is completely absorbed either, some remains in the bowel and is excreted. Calcium (when no Vit D is there) can be about 20-25% absorbed for example. I don't have the magnesium numbers, but when it is not absorbed, it causes loose stools (laxative) and tells you not all is getting absorbed.

The most dangerous way to poison yourself with magnesium is by enema. Overuse of enemas like Fleets, may poison a person with low kidney functions or infants. The last time I looked the stats on this are about 20 people/year. It is just not common, and only happens when people misuse products on the market.

People getting Chemo can require very high doses of magnesium, thru special IVs given with the chemo agent-- The rate of administration of those is very slow so the kidneys to not get overwhelmed. Usually it takes almost a day, for those special situations to be administered. Also other high dose administration with lower amounts than chemo IV are given to women with eclampsia of pregnancy. These amounts are huge, and never seen OTC.