Calcium with Vitamin D Supplement. Oyster shell. Essential for strong bones and teeth. Compare to the ingredients of OsCal 500 + D. Here are some very good reasons to choose this product: Calcium helps maintain bone health. Meets USP dissolution standards; It has Vitamin D, which aids in calcium absorption. Osteoporosis Information: Adequate calcium and vitamin D throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis. Each caplet provides 500 mg of elemental calcium. (These statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any diseases.)