Vitamin B12 (or vitamin B-12) is also called cobalamin. It has a key role in the normal functioning of the brain and nervous system, and in the formation of blood. It is one of the eight B vitamins.
B12 is normally involved in the metabolism of every cell of the human body, especially DNA synthesis and regulation, but also fatty acid and amino acid metabolism.Fungi, plants and animals (including humans) cannot produce vitamin B12. Only bacteria and archaea have enzymes for its synthesis, although animals can convert it to the version they need.