Geri-Care® Joint Health Supplement Calcium / Vitamin D 500 mg - 200 IU Strength Tablet 1,000 per Bottle (556970_BT) 1/BTOyster shell calcium and vitamin D work together to keep osteopenia in check or prevent it altogether. In one tablet, there are 500 milligrams of calcium and 200 IU of vitamin D. Compare to active ingredients in Os Cal 500+D Calcium Supplement with Vitamin D a registered trademark of Aventis Holdings. There are 1,000 tablets per bottle.