What Happens If You Inject B12 Into Fat? PA Relief Figure. Subcutaneous injection into the deltoid area The Australian Immunisation Handbook Subcutaneous (SC) and Intramuscular (IM) Injections Must Knows for Subcutaneous administration: Pinch skin with non dominant hand and hold syringe with dominant hand Always inject: 2 inches away from umbilicus (for abdomen) 3 inches How to inject vitamin B12 into your belly How to Give a B12 Injection: Step By Step Instructions