Rae
Magnesium should always be taken with Calcium 500-1000mg. Calcium Citrate or Carbonate WITH double the amount of Magnesium....preferably Magnesium Oxide. Magnesium is not only good for excellent heart function, circulation, but together WITH Calcium allows for maxium bone health...i.e. allows the Calcium to absorb into the bones....not just "onto" the bones when calcium is taken alone. It has no adverse effect on the kidneys & liver...and loose bowel movements are generally a result of "too much" calcium....but does no harm. Too much Vit. C can also cause loose bowels....not harmful...just inconvenient! RW