NOW combines two nutrients widely studied for their contribution to the health of bones, teeth and the cardiovascular system. Vitamin D3 promotes the transport and absorption of calcium. Recent studies indicate that vitamin D3 may play a role in the proper action of insulin and glucose metabolism and has an important function within the immune system. Vitamin K is essential for the formation of a healthy and strong bone matrix. Vitamin K's role in arterial health revolves around its ability to support efficient calcium metabolism in vascular structures. Vitamin K2 is an active and biologically available form of vitamin K.