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) 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 Common Injections Cheat Sheet Save for Ward Rounds! Insulin Diabetes Subcut 0.51 unit kg Vitamin B12 Deficiency Neuropathy IM 1001000 mcg Tetanus Toxoid