B12 generally has mild discomfort only and nothing else much.

Hello there.  I can understand your concern.  Most of the injections pain just for one second like how a mosquito bites or a pinch. Thats it. It wont be painful and after 5 minutes you wont even know anything has happened. You could also take tab. Neurobion forte once a day after food for a month for better results.  Best regards. Dr. Anil kumar jain. Bangalore.

Not really, its just like other injections. In case you have fear about injections, B12 deficiency can be effectively corrected with tablets alone (T. Meconerve) albeit slowly. It occurs more commonly in strict vegetarians. Rare in people who eat animal based foods unless they have B12 absorption defect in intestines.