Vitamin D is one of the most important vitamins, essential for the normal functioning of the body. The active form of vitamin D3 in this supplement activates the immune system, regulates the central nervous system, stimulates calcium absorption, and supports cognitive functions. Five drops of Grassberg Vitamin D3 Drops contain 50 mcg of vitamin D or 2000 units of vitamin D. Vitamin D3 was discovered almost a century ago, but we continue to learn about its numerous health benefits. In addition to its primary function of ensuring bone mineralization and the normal development of bones and joints, vitamin D3 is very important for the health of hair, nails, and teeth. Vitamin D3 stimulates calcium absorption, improves coagulation, and strengthens the immune system.