Calcium and magnesium have become synonymous with bone health. And as two of the most important nutrients we can feed our body, NOW Calcium-Magnesium Capsules are formulated with a synergistic blend of vitamin D and trace minerals that allow them to work in a highly proficient manner. Derived from the finest grade of calcium carbonate, this source offers more milligrams of calcium per volume than any other commercially available form. Its high bioavailability and perfectly balanced blend make this is one of our most popular calcium products.