Calcium + Vitamin D3 Provides the highest amount of elemental calcium (400mg out of 800mg calcium carbonate) and 200 IU vitamin D3 to promote calcium absorption. Calcium + vitamin D3 ensures optimal muscle, bone and dental health Carefully balanced calcium dosage (no more than 500 mg per serving) for efficient absorption (no elimination from the body). Calcium + Vitamin D3 is a dietary supplement recommended as an additional source of calcium and vitamin D3. The product contains calcium in the form of carbonate (its composition contains 40% elemental calcium) and vitamin D3 (cholecalciferol), which promotes the absorption of calcium in the intestines and its storage in the bones. The use of calcium and vitamin D3 prevents an increase in the production of parathyroid hormone, which is a stimulator of increased resorption bones and bone destruction.