B Complex Vitamins are important for overall health and proper functioning of the body. B Complex Vitamins can not only help the body produce energy, they also can improve appearance of hair and skin. They can speed up chemical reactions in cells, and they can help to fight off infection and protect the body from disease as well. Vitamin B Complex is needed for the proper functioning of almost every process in the body. The B Vitamins all work very closely together, so a deficiency in one may lead to poor functioning of others if not all of them are in good supply. B Vitamins are water-soluble; any excess will be excreted through urine, therefore they need to be replenished on a daily basis.