How to Give Yourself a Shot GoodRx 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 Instructions for B12 Injection Alan Health Insulin Syringes 31 g x 8 mm 1 mL Ultra Fine 100 Box 328418 Ivy Grove Surgery : Self administration of B12 injection Luer Lock Syringes 3 mL without Needle 5 16 inch, 0.3 mL Ultra Fine, 1 Mountainside Medical