While megadoses of up to 2,000 mcg are considered safe in treating B12 deficiency, it’s always best to avoid excessive amounts of any vitamin, especially when it’s not needed. If you think you ...

and you will need injections. Your body stores 1,000-2,000 times as much vitamin B12 as you'd eat in a day, so it can take many years to see symptoms of vitamin B12 deficiency. If you think you ...

For deficiency, 1,000–2,000 mcg daily is required ... Higher doses may be needed for severe vitamin B12 deficiency. 3. Sublingual (under the tongue) or injections are better for those with ...