Calfovit D3 Powder Sachets Calfovit D3 is a calcium & vitamin D3 supplement for the treatment of certain bone conditions in the elderly. Both calcium & vitamin D are found in the diet & vitamin D is also produced in the skin following exposure to the sun.A lack of vitamin D & calcium may lead to reduced bone density & bone fractures. Calfovit D3 may be taken to make up for this deficiency of calcium & vitamin D.