can vitamin b12 injection cause fever Shots at Home: How, Where & How Often to Inject Yourself Best Vitamin B12 Injection Site:

For someone with mild fatigue and slightly low blood levels, a conservative approach of one injection every four weeks might be sufficient

Related reading What Is Vitamin B12 and Why Does the Body Need It

The main thing is to keep up with treatment and watch closely for the best results

It is important to note that when fat cells grow larger, they release nicotinamide N-methyltransferase (NNMT), which slows down metabolism and further leads to weight gain

You could be told you don't need to take the tablets once your levels return to normal and you improved a poor diet - but vegans may need vitamin B12 tablets for life

If I have any of this wrong, feel free to correct me (addressing more experienced members of this forum) The problem with a retest at this point is that after 6 injections, the B12 level will likely be elevated and it will be very difficult to know what the original value would have been