What is vitamin b12 vitamin b12 is a premium quality supplement containing 1000mg of vitamin b12 a vitamin that plays a key role in a number of functions within the body why use vitamin b12 vitamin b12 contributes to many important roles within the body such as macronutrient metabolism immune system function and reduction of tiredness and fatigue vitamin b12 also supports normal psychological nervous functions and normal red blood cell formulation who can benefit this convenient o