Best Vitamin B12 Injection Sites MedHealth 360 Best Vitamin B12 Injection Site: Administering B12 Shots Not all shots are the same here's a guide Injections are a fast, effective way to deliver medications, nutrients, and vaccines directly into the bodybut not all injections are the Injection Techniques Step by Step Guide 1. Intramuscular Injection (IM) 90 Angle Needle Position: Perpendicular to the skin (90 angle) Target Site: Muscle layer Common Sites: Deltoid, Vastus Lateralis,