Vitamin B12 Injections Dosage and Frequency: 8 Essential Guidelines for Adults Liv Hospital 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 Are B12 Patches as Effective as Injections Vitamin B12 injections deliver high doses of this essential vitamin directly into your bloodstream for better absorption than oral supplements to boost energy, support red blood cell production and maintain nerve function.