So I went to GNC today because I've been wanting something to boost my workouts. I want to be able to go the extra mile. I got talked into Pump-HD. It has as much caffeine as three cups of coffee. It's supposed to act like Gatorade mixed with an energy drink. It was my first day using it. I got a lot of energy but It didn't help my workout. I'll keep trying it to see if it improves.