Human body needs adequate amounts of Magnesium in order to absorb calcium and it also needs adequate amounts of Calcium to utilize Magnesium. Vitamin D-3 is also included because it is necessary for both the absorption and utilization of Calcium. [url=http://www.angstrom-mineral.com/angstrom-minerals/angstrom-calcium-magnesium.html]Calcium Magnesium[/url]