Beyond taking a vitamin and mineral supplement, I think most people are better off saving the cash from GNC purchases and making better quality purchases at the supermarket. Vegetables seem to be more expensive than meat, for some reason, which I know from being a vegetarian! A good quality diet, sensible exercise and adequate sleep and no-one should have problems with energy levels unless depression or illness get in the way.
Besides, I think you are either a pill taker or you aren't. I havce made purchases of such regimens at GNC in the past, and never persisted beyond about a week fo actually taking them.
Decidedly, I am a non-pill taker!
Clare