Does B12 Help You Lose Weight? Kansas City Med Spa Still taking vitamin B12 injections? Move over shot. A pill may be just as good. Dr. Leslie Greenberg's Blog Vitamin B12 Deficiency Vitamin B12 deficiency happens when the body does not have enough vitamin B12. Vitamin B12 is important for making healthy red blood cells and keeping nerves Do You Have A Vitamin B12 Deficiency? {symptoms & a simple solution}