Instruction Guide for Intramuscular (IM) Self injection of B12 Methylcobalamin 1mg 5mg Lets do my first B12 injection together This is something Ive been nervous about for a long time, but today I finally did itand it honestly wasnt bad at all. I used the Union Medico needle guide Injections are a fast, effective way to deliver medications, nutrients, and vaccines directly into the bodybut not all injections are the same. There are five main types. Intramuscular (IM) injections deliver B12 Injections for Energy: Benefits and How It Works AZ IV Medics