Calcium and magnesium work together in several key physiological processes including the regulation of blood pressure and healthy muscle function. Magnesium is an essential mineral, playing a key role in over 300 enzymatic and metabolic reactions including helping to deposit and maintain calcium in the bones. Calcium is perhaps best known for its role in the formation and structure of bones and teeth, and it is also integral to nerve transmission, muscle movement and several enzyme systems. Source Naturals Mag/Cal 2:1 supports the body's ability to retain both of the minerals in the bones, muscular tissues and in circulation. The 2:1 ratio of magnesium to calcium is thought by many researchers to be optimal for bone and mineral health, and compliments the average diet that can be low in magnesium-rich foods.