There is an organic compound called vitamin B12.
A vitamin is an organic compound and a vital nutrient that an organism requires in limited amounts . Vitamin B12 . It is one of eight B vitamins . B12 is the largest and most structurally complicated vitamin and can be produced industrially only through bacterial fermentation synthesis , typically used to manufacture B12 for fortified foods and supplements . The vitamer is produced by bacteria as hydroxocobalamin , but conversion between different forms of the vitamin occurs in the body after consumption .