Did you know? 99% of total body calcium is found in the bones and teeth. Itâs not just restricted to women but calcium is important to even men and required right from your birth. Along with Calcium Magnesium and Vitamin D are essential for bone & joint health and promote healthy muscles. 1.GNC Calcium Citrate Plus With Magnesium & Vitamin D3 capsules are formulated with vitamin D and magnesium. 2. GNC Calcium Citrate Plus With Magnesium & Vitamin D3 is a dietary supplement that supports bone health. 3. Vitamin D intake aids calcium absorption while the magnesium helps vitamin D function properly.