From the Guidelines
The recommended dosage of vitamin B12 for treating deficiency is hydroxocobalamin 1 mg intramuscularly, with the frequency depending on the presence of neurological involvement, as outlined in the British Obesity and Metabolic Surgery Society guidelines 1. For patients with vitamin B12 deficiency and possible neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered on alternate days until there is no further improvement, then hydroxocobalamin 1 mg intramuscularly every 2 months 1. In cases without neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months for life 1. Key points to consider when treating vitamin B12 deficiency include:
- Immediate treatment is essential, especially in cases with possible neurological involvement, to prevent further complications 1.
- Folic acid supplementation should not be initiated before treating vitamin B12 deficiency, as it may mask underlying vitamin B12 deficiency and precipitate subacute combined degeneration of the spinal cord 1.
- Maintenance treatment is crucial to prevent recurrence of deficiency and should be administered lifelong 1.
From the FDA Drug Label
1 mg per day may result in hematologic remission in patients with vitamin B12 deficiency. Doses of cyanocobalamin exceeding 10 mcg daily may produce hematologic response in patients with folate deficiency. Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives. The need for vitamin B12 is increased by pregnancy and lactation. Amounts of vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for pregnant women (4 mcg daily) should be consumed during pregnancy. Amounts of vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for lactating women (4 mcg daily) should be consumed during lactation. Intake in children should be in the amount (0.5 to 3 mcg daily) recommended by the Food and Nutrition Board, National Academy of Science-National Research Council.
The recommended dosage of vitamin B12 varies depending on the condition and patient population:
- For patients with vitamin B12 deficiency, a dose of 1 mg per day may be used.
- For patients with folate deficiency, doses exceeding 10 mcg daily may produce a hematologic response.
- For pregnant women, the recommended daily dose is 4 mcg.
- For lactating women, the recommended daily dose is 4 mcg.
- For children, the recommended daily dose is 0.5 to 3 mcg.
- For patients with pernicious anemia, monthly injections of vitamin B12 are required for the remainder of their lives 2.
From the Research
Dosage of Vitamin B12
- The recommended dosage of vitamin B12 varies depending on the individual's condition and the severity of the deficiency 3, 4, 5.
- For patients with vitamin B12 deficiency, oral administration of high-dose vitamin B12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms 3.
- A study on patients with Crohn's disease found that oral cyanocobalamin at a dose of 1 mg/day was effective in treating vitamin B12 deficiency and maintaining correct cobalamin levels in the long term 4.
- Another study suggested that the lowest dose of oral cyanocobalamin required to normalize mild vitamin B12 deficiency is more than 200 times greater than the recommended dietary allowance, which is approximately 3 μg daily 6.
- Experts agree that high-dose oral B12 at different frequencies may be considered for long-term treatment, and prophylactic B12 supplementation should be considered for specific high-risk groups 5.
- The use of vitamin B12 in patients with elevated serum homocysteine levels and cardiovascular disease does not reduce the risk of myocardial infarction or stroke, or alter cognitive decline 3.
Specific Dosage Recommendations
- Patients who have had bariatric surgery should receive 1 mg of oral vitamin B12 per day indefinitely 3.
- Daily doses of 647 to 1032 μg of cyanocobalamin were associated with 80% to 90% of the estimated maximum reduction in the plasma methylmalonic acid concentration 6.
- Supplementation with cyanocobalamin in daily oral doses of 2.5,100,250,500, and 1000 μg was associated with mean reductions in plasma methylmalonic acid concentrations of 16%, 16%, 23%, 33%, and 33%, respectively 6.