Bio-Avail Calcium provides four unique forms of highly-absorbed calcium to ensure maximum absorption of this important macromineral. While most calcium supplements use only a single source of calcium, which can easily overwhelm a single pathway of absorption and limit uptake, this calcium takes advantage of four unique pathways of absorption by providing calcium in the hydroxyapatite, di-calcium malate, calcium citrate, and glycinate forms. In addition, Bio-Avail Calcium includes vitamin D and phosphorus, both critical nutrients for bone mineralization and remodeling. Calcium is required for strong bones, heart health, muscle function, nerve transmission, intracellular signaling, and hormonal secretion.