For the past few years I have been administering B12 injections weekly. Your body needs B12 for healthy cell growth and function. It improves brain function (which I need desperately), memory, nervous system, and so on. It also gives you a boost of energy and alertness. B12 tablets are not absorbed very efficiently in the body and injections gives your body the best ability to absorb it. I may turned into a bit of a junkie because I have used it during periods of fatigue induced by my RA. It may be psychological, but I feel it helps with my energy levels. You can't overdose on B12 and your body doesn't store excess. I am curious to know if any of you take B12 injections or have in the past.