We dislikes GNC, peddlers of high-priced nonsense. It's hard to believe you would be sensitive to that amount of caffeine or B12, but the other odd botanical ingredients are suspect. One should avoid shotgun products (things that contain lots of different ingredients) generally. If you are looking for boosted energy for the workout, some fruit plus maybe a Red Bull-equivalent drink (generally containing caffeine and taurine, and look for the sugar-free variety. many to choose from) might work. An hour beforehand is about right.