B12 Shots - Best place to shoot

My GYN told me to take my B12 shots in my thigh but my surgeon said I could take them in my stomach.  Where is the best place to take the shot and why? Thanks!

B12 should be intramuscular, and that means your thigh.  Subcutaneous would mean your stomach.  

Into a MUSCLE. Likely not your stomach unless you have the 'six-pack' abs. You can use your upper arm or thigh...

Thanks, Sara!  Just curious but can you tell me why?