Vitamin B12 Information

Vitamin B12 is a water-soluble vitamin that is essential for healthy blood and nerve cells. It is bound to protein in food and is released by stomach acid and absorbed into the bloodstream. People who are unable to absorb it into the bloodstream may have vitamin B12 deficiency, which can lead to serious problems, such as anemia or severe nerve damage.
To overcome these absorption problems, vitamin B12 injections are often used. The vitamin is also available in tablet, nasal spray, capsule, oral liquid, and patch form. Most people taking these supplements do not experience side effects, even at high doses. However, a few rare side effects were reported in clinical trials, such as diarrhea, rash, and blood clots in the legs.
(For more information, including safety issues to discuss with your healthcare provider, click Vitamin B12.)
Last reviewed by: Arthur Schoenstadt, MD