Vitamin B12, also known as cyanocobalamin helps your body use nutrients - carbohydrates and fats for energy. It also is important for normal blood cell and nerve function.
Most people get Vitamin B12 from their diet but certain conditions can impede that e.g. poor nutrition, certain medications, stomach/intestinal problems, infection, cancer.
Serious Vitamin B12 deficiency may result in anemia, stomach problems and nerve damage.
Vitamin B12 injections allow for quicker absorption into the body and you feel the effects (increased energy, focus, improved sleep) within 48 - 72 hours and the effects last for about 1 week.