Julie M. Sease, PharmD, BCPS, CDE, Senior Associate Dean at the College of Pharmacy at the University of South Carolina, argues that vitamin B12 supplements do not improve chronic fatigue syndrome symptoms.
Does Vitamin B12 Help Relieve Fatigue?
Julie M. Sease, Pharm D, BCPS, CDE
January 05, 2009
Question
What does the medical literature state about the effectiveness of vitamin B12 for the treatment of fatigue in patients without vitamin B12 deficiency?
Response from Julie M. Sease, PharmD, BCPS, CDE
A Google search using the terms "fatigue" and "vitamin B12" (cyanocobalamin) generates about 439,000 results. Many of these are links to alternative or complementary medicine Web sites that suggest cyanocobalamin as a treatment for fatigue and tiredness. It is no wonder, then, that patients present to their doctors' offices or pharmacies requesting vitamin B12 and further information about the usefulness of this vitamin for fatigue.
Vitamin B12 is usually supplied as either hydroxycobalamin (preferred in parts of Europe) or cyanocobalamin (used most frequently in the United States).[1] Cyanocobalamin maintenance therapy is often administered orally at 1,000 mcg daily or intramuscularly (IM) at 1,000 mcg monthly. There is evidence that patients have been prescribed vitamin B12 injections without documented B12 deficiency,[2] and the likelihood of a physician treating a patient without assessing for B12 deficiency seems to increase with the patient's age. So, what is the clinical trial evidence to support the use of vitamin B12 for fatigue in the absence of vitamin B12 deficiency?
Claims that vitamin B12 supplementation improves well-being in patients who are not deficient in the vitamin can be found in the literature dating as far back as 1952.[3] It was not until 1973, however, that a controlled trial evaluating this claim was published.[4] In this small study, 29 subjects with a normal baseline vitamin B12 level were enrolled into a crossover within-subject study. Subjects were randomized to receive either hydroxycobalamin 5 mg by IM injection twice weekly or matching placebo for 2 consecutive weeks. After a 2-week washout period, each subject received the opposite treatment for the remaining 2 weeks of the 6-week trial. Response was determined using self-assessment cards with questions about appetite, general feeling of well-being, mood, fatigue, sleep, and the effect of injections. If the score was higher for an item while the patient was receiving hydroxycobalamin, it was determined that the patient preferred hydroxycobalamin. The converse was true for placebo.
