Dr. prescribed B12 injections. Pharmacy only gave me vials. Where do you get your needles and syringes? What size?? Where do I inject? : r B12_Deficiency How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust B12 Injection sites + How to use B12 Shots Safely How to self administer subcutaneous B12 injection., 1. Withdraw proper dosage from vial into an insulin syringe, 2. Clean site of injection (abdomen or other proper site), 3. Pinch the skin where you