Vitamin B12 (cobalamin) is a nutrient that helps keep your body's blood and nerve cells healthy and helps make DNA, the genetic material in all of your cells. Vitamin B12 also helps prevent megaloblastic anemia, a blood condition that makes people tired and weak. This supplement is the activated form of b12 (it has already been methylated), making it more available for your body to utilize! Many B12 supplements use cyanocobalamin, which is the artificial form and not found in nature. We use the already methylated and activated form, methylcobalamin.