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 ...

Higher doses of up to 1,000 mcg, or 1 milligram (mg), may be necessary for some (13 Trusted Source). Pregnant people. ... Vitamin B12 injections may lead to skin conditions, ...

However, the neurologist told me to take 2,000 mcg of B12 daily. My multivitamin ... for vitamin B12 is 2.4 mcg. (There are 1,000 micrograms in a ... or they would prescribe B12 injections.