Vitamin B12 Fact Sheet

Your body's cells require a nutrient called cyanocobalamin for proper metabolic functioning. Also known as vitamin B12, this chemical is not associated as much with possible alternative health uses, although it is sometimes marketed as a weight loss aid in addition to a few other possible benefits. Also, too little of it can cause a serious anemic condition that can be further complicated by interaction with a different member of the vitamin B family.

Vitamin B12 is used in a complicated process of molecule exchange as part of the metabolism of cells, extracting energy from fat and protein. It is absorbed from food by a chemical in the stomach called "intrinsic factor," and people who have had stomach problems or medications that may have affected their ability to create enough intrinsic factor are in danger of being deficient in B12.

A defiency in B12 can lead to a dangerous condition called "pernicious anemia," which mimics normal anemia but can only be cured with a vitamin B12 supplement. Symptoms of anemia usually include weakness and fatigue, as well as a pale look and shortness of breath. The anemia itself can actually be a useful flag for more serious problems, but may be "compromised" by supplementation with vitamin B9.

For more information, read our article on vitamin B12 deficiency.

Vitamin B12 is often marketed as an aid to weight loss, and many weight loss clinics offer B12 injections as part of their programs. However, research is scare on this despite positive results from personal reviews. Does it actually help with weight loss? Is there any evidence at all? Well, B12 is also often touted as an energy booster, so some theorize it may help increase the ability and motivation to exercise.

Using vitamin B12 as a weight loss supplement may be acceptable as it has no known side effects or longterm dangers. A few people may have some allergic reactions to it, sometimes to the point of needing treatment. And there is a possible unsafe situation that can arise if folic acid is being taken as a supplement without also taking B12.

Overall, vitamin B12 is useful primarily for those who are deficient in it, such as the elderly and vegetarians who do not eat dairy. If you are a person who is possibly lacking in B12, or you have some symptoms of anemia, please see your doctor before starting any supplementation. B12 for weight loss may or may not be helpful, and it is up to you to decide if it's something you want to try. Before buying a supplement, please see our section on what factors to look for in a vitamin B12 supplement.