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 Buy Vitamin B12 Injections, 2000mcg Vitamin B12 Direct 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 Vitamin B12 Injection Side Effects and Safety