How to Give a B12 Injection: Step By Step Instructions How to Give a B12 Injection: Step By Step Instructions 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 body but not all injections are the same. Subcutanous injection self administration South Tees Hospitals NHS Foundation Trust B 12 (Methylcobalamin) Therapy MedClub by Dr Jenn