There is a trick to using this product: taking it on an empty stomach helps it gets into your blood system faster. And personally, two tablets is a better dose for me. Here is what you need to know.
I am retired now, but still use it occasionally. For myself, as well as for the many colleagues I have shared this product with, we worked hard and would find ourselves dog tired and swearing we could not make it through the entire day. But once we took this product, the day started going smoothly and the exhaustion miraculously vanished. It works gradually, not suddenly. It kind of sneaks up on you, so you really don't realize the effect until you notice you are functioning well.
My husband also takes it when he finds himself driving, already tired, and still looking at a long day ahead. He swears by it.
The other nice thing we have noticed about taking this product is, by evening, you will have no problem sleeping. Unlike caffeinated drinks, you will not notice any rapid heart beat, and as it wears off, there will be no "low" while you come down.
Good product.