B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust CYANOCOBALAMIN INJECTION, USP 30000 mcg 30 mL (1000 mcg mL) 30 mL VIAL If you have a low vitamin B12 level, injections can go a long way toward improving your health and well being. But if your B12 level is normal, don't fall for claims that