Vitamin B12 has been firmly established as an essential nutrient that plays a key role in the creation and maintenance of the body’s cells. Most of the time Vitamin B12 shots are prescribed for people whose natural ability to absorb the nutrient has been compromised since a deficiency can result in many serious health problems. However, since Vitamin B12 is generally safe and excess amounts are either stored in the body of safely excreted, it has become one of the most popular supplements on the market today. While many of the claims related to the positive benefits of a Vitamin B12 shot do have at least some clinical evidence supporting the basic contention, other claims are more far-fetched. The idea of Vitamin B12 serving as a mood enhancer is one of these claims for which there is little actual evidence, though many users still claim that the nutrient, taken as a supplement, does improve their mood.
The basis of the claim is the relationship between Vitamin B12 and S-adenosyl-L-methionine (SAMe), which is also sold as a supplement. SAMe is not a neurotransmitter and does not directly affect mood, but it does improve transmethylation reactions, which in turn, improves the effectiveness of the brain’s neurotransmitters. Vitamin B12 enters the picture because it is a necessary substance for the creation of SAMe, therefore people with B12 deficiencies frequently create less SAMe, which results in decreased neurotransmitter effectiveness. As is apparent, Vitamin B12 is far removed from any actual mood enhancing the process, which is governed by neurotransmitters in the brain. It is certainly true that there can be a mood enhancement effect for people suffering from a Vitamin B12 deficiency, but realistically this is uncommon among most well-nourished people.
The general consensus among medical professionals is that taking supplemental Vitamin B12 plays no real role in mood enhancement and that people reporting this effect receive it from the placebo effect. Further, since SAMe is directly available as a supplement in its own right, Vitamin B12 is probably superfluous for most people. Nevertheless, it can not be denied that many people do report mood enhancement resulting from Vitamin B12 shots, so it is impossible to say that this is not a real effect of taking the supplement.