Magnesium Chloride is absorbed into the body really well. I bought a 10 kilo bag of it online. I use this in my baths and also put it in my drinking water.
Magnesium chloride draws water like crazy. Just try it: put some on a saucer and leave it for an hour. Depending on the humidity, the magnesium flakes will be wet or even completely dissolved into the water they attracted.
MgCl2 flakes hold about 47% MgCl2 (from here).
Molecular weight of Mg is 2430500 g/mol
Molecular weight of Cl– is 35453 g/mol, so of Cl2 about twice that: 70906 g/mol
Together, the molecular weight of MgCl2 is about 2430500 + 70906 = 2501406 g/mol
One cup of MgCl2 flakes holds about 51 gram of flakes
Now for the calculations:
- Mg in MgCl2: 2430500 / 2501406 * 100 = 97.165%
- There is 51 * 0,47 * 0,97165 = 23.29 g of Mg / cup MgCl2
- There are 250 / 5 = 50 teaspoons in a cup
- There is 23.59 / 50 = 0.466 g = 466 mg of Mg / tsp MgCl2
I usually put 1/16 teaspoon into half a liter of water to drink. I do this several times a day. 1/16 teaspoon would then hold about 466 / 16 = 29 mg of elemental Mg.