The recommended intake of vitamin B12 for people older than 14 is 2.4 micrograms a day. People who follow a vegetarian or vegan diet may need vitamin B12 supplements. Vitamin B12 injections can treat ...

You cannot overdose on vitamin B12 because any excess you simply pee out. If you get b12 shots, you may experience side effects like dizziness, nausea, and fatigue. It is possible to have elevated B12 ...