It does nothing unless your B-12 deficient... I tried the injections years ago and had a routine blood test come back with very high red blood cell count... That was fun.
What did work to help increase my appetite was a can of diet coke 30 minutes before I was due to eat? Strange... but it worked for me.
I picked that trick up by watching fat chicks at maccas haha

As stated B-12 doesn't do a whole lot for your appetite. It's great for energy and nerve function though. I'm a little jealous of those prices you guys mentioned. I thought I had the hookup, but I am way over paying. Guess I will need to comparison shop.

I love differing opinions. B12 does nothing for my appetit. It does give me a boost in energy which is noticeable but nothing crazy. These days I only use it for 1 thing and that is to cut test suspension.

i use it its cheap for me 10ml for 4 bucks

I love the shit outa my b12 complex, it has b1 b6 b12 d-panthenol. Its pretty cheap at $4 for 8 2ml vials. I notice a good appitite increas as well as energy and its suppose to help with focus.