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 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 Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief Benefits of B12 Shots for Energy and Focus How Often Will I Need Vitamin B Complex Injections? How Often Should I Take Vitamin B12 Injections