B12 vitamin Store Intramuscular vs Subcutaneous Injections for vitamin B12 supplements. B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Is It Okay To Use A B12 Injection With Insulin Syringes? 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