Vitamin B12 Screen Dublin Health Screening If you have a low vitamin B12 level, injections can go a long way toward improving your health and well being. But if your B12 level is normal, don't fall for claims that Beyond the Needle: Unpacking Vitamin Injections and Your Body Weight B12 Injection sites + How to use B12 Shots Safely Benefits of B12 Shots for Energy and Focus What does a B12 shot do, and how does it affect the body?