Vitamin B12 Injections: Benefits and Risks Injection is a technique for delivering drugs by parenteral administration, that is, administration via a route other than through the digestive tract. Parenteral injection includes subcutaneous, intramuscular, intravenous, intraperitoneal How To Self Inject B12 Needle Injection Techniques Every Nurse Should Know! Whether you're prepping for your NCLEX or brushing up on your skills, here's a quick breakdown of the most common injection routes you'll encounter Vitamin B12 absorption pathways and main factors and organs involved: Download Scientific Diagram