Calcium Carbonate

Calcium carbonate is one of the oldest and most widely used mineral supplements in clinical medicine. It’s essentially a salt of calcium derived from natural sources like limestone, marble, or oyster shells, but in the pharmaceutical world, we look at it as a reliable, high-density source of elemental calcium. For context, calcium carbonate contains about 40% elemental calcium by weight, which is significantly higher than calcium citrate (21%) or calcium gluconate (9%).