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 When that Vitamin B12 injection kicks in , B12 helps boost your energy, improve mood, support brain function & metabolism, and even strengthen hair, skin + nails , Who doesnt love a healthy How Quickly Does B12 Shot Work? Does It Help to Lose Weight? 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