B12 Shots Benefits & How to Use Them For Weight Loss How Long Does A Vitamin B12 Shot Last How Often Should I Get a B12 Shot? An Expert Guide How Long Does It Take For B12 Injections To Work? Main benefits of B12 injections 1) Increased energy & reduced fatigue B12 helps convert food into usable energy Deficiency often causes tiredness, weakness, and low stamina 2) Healthy red blood cells Prevents B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics