Vitamin B12 is a water-soluble vitamin that plays an important role in many functions of the body such as DNA synthesis and red blood cell formation. It is found in many food sources however supplementing with vitamin B12 is now very common due to the widespread deficiency. Deficiency is more prevalent in people with vegan or vegetarian diets as vitamin B12 is mainly found in animal products such as fish, meat and dairy. Available supplements come in the forms of liquids, tablets and injections however the latter is preferred as it is absorbed directly into the bloodstream.
There is no upper limit for the consumption of B12 as the risk of toxicity is extremely low.