Not all shots are the same here's a guide Injections are a fast, effective way to deliver medications, nutrients, and vaccines directly into the bodybut not all injections are the B12 vitamin Store Intramuscular vs Subcutaneous Injections for vitamin B12 supplements. Types of injections explained! Understanding the angles: intramuscular (im) : injects deep into the muscle at 90. subcutaneous (sc) : goes under the skin at 45. intravenous (iv) : 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!