1. He already has b12 tabs.
2. Not everyone uses injectable B12.
3. When you add b12 you are injecting more volume, and that can lead to more pain/discomfort.
4. Air is free and available to everyone.
5. Injectable B12 is water based. Oil floats on top of water so to have the B12 at the plunger end the injection must be done upside down.
6. Because injectable B12 is water based it can actually help some esters to crystallize, and that hurts.
7. B12 wont do anything to help keep the juice from leaking out of the injection site, air will.
If you want more reasons I can probably come up with some.
