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 Cyanocobalamin (b12) Injection 2,000 mcg mL 30mL Conquer Pharma Intrav My Store What Happens If You Inject B12 Into Fat? PA Relief A Retired RN About Vitamin B12 Injections Not All Shots Are Created Equal Your Quick Guide to Injection Types , Ever wondered why some shots go in your arm muscle and others just under the skin? Heres the breakdown:, Intramuscular (IM)