Even though the food we take is rich in all nutrients, we may end up getting some in excess and some lower than the required amount. In a normal person these symptoms might not be so dramatically visible, but in some severe cases they turn fatal. To fight the deficiency, these supplements are provided to meet the bodies’ needs. The dose is always determined by the doctors. Some times in administered cases the patient might end up taking an overdose. Just as excess of anything is bad, vitamin b12 overdose is also harmful. Though it might be known as energy booster, it is not good to have excess of it. We shall understand why.