Dear I.F.: The DV (a replacement for what we used to call the recommended daily allowance, or RDA) for vitamin B12 is 2.4 mcg ...

Though doses of up to 2,000 mcg of vitamin B12 are considered safe, it’s best to speak with a doctor to find out whether taking a supplement is necessary. Most people can fulfill their B12 needs ...

For deficiency, 1,000–2,000 mcg daily is required. On the other hand, 250–500 mcg daily is good for maintenance. Higher doses may be needed for severe vitamin B12 deficiency .

The absorption of vitamin B12 is about 2% at doses of 500 mcg or 1.3% at a dose of 1,000 mcg. Therefore, if someone consumes vitamin B12 less frequently, they will need a higher total amount to ...

Low vitamin B12 can have neurological and psychiatric manifestations. If your neurologist or oncologist was worried about pernicious anemia, they would recommend oral doses of 1,000-2,000 mcg ...