Reacted Calcium provides three unique forms of highlyabsorbed 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, Reacted Calcium takes advantage of three unique pathways of absorption by providing calcium in the hydroxyapatite, di-calcium malate, and glycinate forms. In addition, Reacted Calcium includes vitamin D and phosphorus, both critical nutrients for bone mineralization and remodeling.