Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief Treating Severe Vitamin B12 Deficiency B12 IM Injection 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 How to self administer subcutaneous B12 injection., 1. Withdraw proper dosage from vial into an insulin syringe, 2. Clean site of injection (abdomen or other proper site), 3. Pinch the skin where you