Methylcobalamin is one form of vitamin B12. The other forms, cyanocobalamin and hydrocobalamin, are more difficult for the body to utilize and require several metabolic changes before becoming available. Vitamin B12 is used by the body for enzymatic functions including the creation of compounds like methionine. Vitamin B12 is utilized for energy production by the metablism, especially with lipids. Vitamin B12 is also used in the preservation of the myelin sheathes (protective covering) of your nerve cells as wella s the normal functioning of the nervous system.