How Often Should You Get Vitamin B12 Injections? B12 Injection Frequency: How Often Should You Get a B12 Shot? Liv Hospital B12 Injections: Who Should Get Them and How Long Do They Last? Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief 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