I was looking for a good pre-workout supplement and was surprised to learn that Hyper FX had De-Aspartic Acid (DAA) in it. I decided to give it a shot after hearing all about the wonders of DAA. In terms of energy, Hyper FX gave me exactly what I expected: a nice physical boost and increased mental sharpness. I didn't feel jittery or over-caffeinated either, so that was nice. Overall a very good product.