Here is the trick the industry runs, and how to catch it. Magnesium glycinate is a compound: magnesium bound to the amino acid glycine. Only about 14% of a fully-reacted magnesium glycinate powder is elemental magnesium — the part your body actually uses. The rest is the glycine carrier.
So a label can say "Magnesium Glycinate 400 mg" and be telling the truth about the powder while delivering only ~56 mg of usable magnesium — roughly one-seventh of a real dose. That gap is where fairy-dusting hides. To actually deliver 400 mg of elemental magnesium, you have to put in about 2,800 mg of glycinate powder. We do. Here's the whole stick, shown the honest way:
Figures reflect the target formula and are finalized against each batch's Certificate of Analysis below. Elemental-magnesium percentage varies slightly by supplier and reaction completeness; the COA is the source of truth, not this table.