Vitamin B12 (Cyanocobalamin) is a water soluble vitamin necessary for energy production; for nervous system function; for the production of acetylcholine, a neurotransmitter that helps with memory and learning; for the synthesis of red blood cells; and for producing the genetic materials, DNA and RNA. Vitamin B12 is the most complex of the vitamins and is the only naturally occurring organic compounds that contains cobalt. Cyanocobalamin is the most stable form of vitamin B12. As the B vitamins work together, it makes sense to take a B complex when taking high amounts of any B vitamin.