While vitamin B12 is best known for combating fatigue, it has many other critical functions in the body. In fact, many people who lack B12 do not even have significant fatigue, according to a report in Mother Earth News. Perhaps most importantly, B12 is also responsible for forming myelin, which insulates nerve fibers and produces neurotransmitters. A deficiency of B12, therefore, may lead to a whole bunch of problems with the nervous system. Fortunately, supplementation can help maintain normal blood levels. B12 in the form of methylcobalamin, at 2,000 mcg per day, is recommended for oral use.
Source: Mother Earth News