GNC Calcium Plus is enriched with potent calcium and also has the goodness of vitamin D3 and magnesium, both of which are needed for proper calcium absorption and better metabolism. Magnesium and vitamin D3 work in synergy for optimum calcium absorption. Magnesium helps in conversion of Vitamin D in its active form known as Calcitriol, which in turn plays a major role in improving the concentration of Calcium. GNC Calcium has been formulated to meet the Indian body needs, and it has combined three powerful ingredients clinically researched and documented to work better together.