How often do you obtain B12 injections for weight loss? 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 How Quickly Does B12 Shot Work? Does It Help to Lose Weight? Gym goers spending monthly on vitamin B and C injections Have a f*cking word with yourself. Both are water soluble, so don't stick around for long in your system (12 14hrs) hence Who Needs B12 Injections, How Much and How Often? InVita Wellness