From the Guidelines
The standard oral Vitamin B12 dose for treating Vitamin B12 deficiency is 250-350 μg/d or 1000 μg/wk sublingual, as recommended by the most recent guidelines 1. When treating Vitamin B12 deficiency, it is essential to consider the severity of the deficiency and the patient's ability to absorb the vitamin.
- For mild deficiencies, a dose of 250-350 μg/d may be sufficient, while more severe cases may require higher doses of up to 1000 μg/d sublingually or even intramuscular injections 1.
- The sublingual form of Vitamin B12 is preferred for oral supplementation, as it allows for better absorption and can be more effective in treating deficiencies 1.
- It is crucial to monitor the patient's Vitamin B12 levels regularly during treatment to ensure an adequate response and adjust the dose as needed 1.
- Underlying causes of the deficiency, such as pernicious anemia or gastric surgery, should also be addressed simultaneously to prevent further deficiencies 1.
- High oral doses of Vitamin B12 can be effective in treating most deficiencies due to the passive diffusion mechanism in the intestines, which allows approximately 1% of the dose to be absorbed even without intrinsic factor 1.
From the Research
Standard Oral Vitamin B12 Dose
The standard oral Vitamin B12 (Cobalamin) dose for Vitamin B12 deficiency can vary, but several studies provide guidance on effective dosing.
- A 1994 study 2 suggests that oral therapy with 300-1000 micrograms per day may be therapeutically equivalent to parenteral therapy.
- A 2017 study 3 recommends oral administration of high-dose vitamin B12 (1 to 2 mg daily) for correcting anemia and neurologic symptoms.
- A 2009 study 4 recommends prescribing 1000 microg/day vitamin B12 orally for patients with vitamin B12 deficiency, unless they have problems with swallowing or treatment compliance or have severe clinical symptoms.
- A 2015 study 5 suggests an oral vitamin B12 dose of 1 mg daily for a month, and then a maintenance dose of 125 to 250 µg for patients with dietary insufficiency and 1 mg daily for those with pernicious anaemia.
- A 2017 study 6 found that oral cyanocobalamin at a dose of 1 mg/day was effective in treating vitamin B12 deficiency in patients with Crohn's disease.
Key Findings
- Oral vitamin B12 supplementation can be as effective as parenteral administration for correcting vitamin B12 deficiency 3, 4, 6.
- The effective oral dose of vitamin B12 can range from 300-2000 micrograms per day 2, 3, 4.
- Higher doses (1-2 mg daily) may be necessary for patients with severe deficiency or severe neurologic symptoms 3.