Now offering B12 injections! If these symptoms sound all too familiar, it might be time to check your vitamin levels. B12 injections may be absorbed up to 90% more effectively than oral Updated: Vitamin B12 Deficiency and Weight Gain Modern Body Clinic How Quickly Does B12 Shot Work? Does It Help to Lose Weight? Can Vitamins Make You Hungry? Vitamin B12 injections can be very beneficial! , 1. Boosts Energy and Reduces Fatigue, B12 helps your body convert food into energy at the cellular level. Low B12 can cause tiredness, weakness, and