Cal-6 + Mg.?, provided by Douglas Laboratories, is a special chelate complex of 6 sources of calcium with magnesium and other ingredients to assist the body in maintaining healthy bone structure. Calcium is a primary mineral for building the strong structure of bones and teeth. Cal-6 + Mg.? may be a useful dietary supplement for those who wish to increase their intake of calcium and other nutritional factors for maintaining the function and structure of their bones. The adult human body contains approximately 1,200 g of calcium, about 99% of which is present in the skeleton, and 20-30 g of magnesium with about 60% located in bone. Bone is constantly turning over, a continuous process of formation and resorption. In children and adolescents, the rate of formation of bone mineral predominates over the rate of resorption. In later life, resorption predominates over formation. Therefore, in normal aging, there is a gradual loss of bone. Intestinal calcium absorption ranges from 15 to 75% of ingested calcium. Vitamin D is a key regulatory hormone for calcium and bone metabolism. Adequate Vitamin D status is essential for ensuring normal calcium absorption and maintenance of healthy calcium plasma levels. Magnesium absorption is independent of Vitamin D status and ranges from 30 to 60% of ingested magnesium. Osteoporosis, a condition of reduced bone mineral density that can increase risk of fractures, affects a large proportion of the elderly in developed countries. Caucasian and Asian women typically have low peak bone densities, and therefore, are at the greatest risk of developing osteoporosis. It is generally accepted that obtaining enough dietary calcium throughout life can significantly decrease the risk of developing osteoporosis. Among other factors, such as regular exercise, gender and race, calcium supplementation during childhood and adolescence appears to be a prerequisite for maintaining adequate bone density later in life. But even elderly osteoporo