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! Types of Injections Injections are a common medical procedure used to administer medications or vaccines. Here are some common types: # 1. Intramuscular (IM) Injections Injected into a muscle, usually Cyanocobalamin: Package Insert Prescribing Information Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief What Happens If You Inject B12 Into Fat? PA Relief 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 )