Adequate calcium and vitamin D throughout life as part of a well-balanced diet may reduce the risk of osteoporosis. Adequate calcium is also important for teens and young adults and post-menopausal women. In just one tablet Nature Made Calcium 600 mg with Vitamin D provides 600 mg of calcium and 400IU (10 mcg) of vitamin D3 to help meet your daily need for calcium. Calcium and vitamin D help support strong bones and teeth. Vitamin D helps improves calcium absorption. Two tablets provide 1200 mg of calcium for those with a higher recommended daily allowance such as adults 50+.