Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta analysis Irish Journal of Medical Science (1971 ) B12 Injections at Home Safety Guide for Self Administration Infusion For Health Understanding the 4 main types of injections makes medical knowledge simple and clear. Intramuscular, Subcutaneous, Intradermal & Intravenous each one plays a different role in treatment. Stay informed, stay safe! Best Vitamin B12 Injection Site: Administering B12 Shots Cyanocobalamin (B12) Products American Regent 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)