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 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 How Long Does It Take Vitamin B12 Injections to Work? How Quickly Does B12 Shot Work? Does It Help to Lose Weight? 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 B12 Injections for Weight Loss: Spa Black's Guide