Vitamin b12 dosage recommendations
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General Vitamin B12 Dosage Recommendations
Current general recommendations for vitamin B12 intake in healthy adults range from 1.4 to 3.0 micrograms (µg) per day, which is based on the amount needed to maintain normal blood and body stores and to compensate for daily losses of the vitamin 39. However, some research suggests that daily losses may be higher, and intakes between 3.8 and 20.7 µg may be needed to fully compensate for these losses, especially in older adults .
Vitamin B12 Supplementation for Deficiency
For individuals with vitamin B12 deficiency, higher doses are required. Initial oral therapy often involves 500 µg per day for 4–6 weeks, or intramuscular injections of 1000–1500 µg per day for 6–8 weeks. After this initial phase, maintenance therapy depends on the cause of deficiency: 250–500 µg per day orally for diet-related deficiency, and up to 1000 µg per day orally or 1000 µg per month by injection for absorption disorders . Oral doses of 1000 µg daily are also effective for treating pernicious anemia and are considered a suitable alternative to injections .
Special Populations and High-Risk Groups
Older adults, vegans, vegetarians, and people with absorption issues (such as those who have had bariatric surgery or have gastrointestinal disorders) are at higher risk for deficiency. For these groups, supplementation is recommended: adults over 50 and those with restricted diets should consume fortified foods or take supplements . After bariatric surgery, daily oral doses of 1000 µg are generally sufficient to prevent deficiency, while lower doses (≤15 µg) are inadequate . In bariatric patients, doses of 350–1000 µg daily are commonly used, with 1000 µg being most effective 46.
Dosage in Food Supplements and Safety
For the general population, food supplements providing up to 20 µg of vitamin B12 daily are unlikely to cause pharmacological effects, while higher doses (≥200 µg/day) may be considered medicinal and are used to correct deficiency and related symptoms . Doses of 50 µg may help correct biochemical markers in some deficient patients, and special medical foods for those with absorption problems may contain 100–150 µg per day .
Vitamin B12 Dosage for Specific Conditions
- Stroke Prevention: Combined supplementation with vitamin B12 (≤0.4 mg or 400 µg per day) along with folic acid and vitamin B6 has been shown to reduce stroke risk in areas without folic acid fortification .
- Recurrent Aphthous Stomatitis: A daily sublingual dose of 1000 µg for six months has shown benefits in reducing outbreaks and symptoms, though more research is needed .
Conclusion
Vitamin B12 dosage recommendations vary based on age, health status, and risk factors. For healthy adults, 1.4–3.0 µg per day is generally sufficient, but higher doses are needed for those with deficiency or absorption issues. Oral supplementation of 1000 µg daily is effective for most deficiency cases, including after bariatric surgery and in pernicious anemia. Supplementation is especially important for older adults, vegans, and those with gastrointestinal disorders. For the general population, food supplements should not exceed 20 µg daily unless treating a diagnosed deficiency.
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