B12 vitamin Store How to inject B12 in your arm Why do nurses and doctors prefer giving injections on the buttocks? How to Give a B12 Injection: Step By Step Instructions Common sites for intramuscular injections Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief Safe intramuscular (IM) injection in the gluteal region is given in the upper outer quadrant to avoid sciatic nerve injury. Incorrect site selection (inner, lower, or medial areas) increases the risk of