I recently started using jack3d after trying a long list of pre-workout supps. such as superpump 250, santight, purple wrath, no-xplode, ect. Either they made me nautious, gave me a bad migrane, made me feel jittery or nothing at all. I finally tried jack3d and this is hands down the best supp I have used. I am a 34 yr. old female in case your wondering. No jitters, no headache, no upset stomache. Just pure energy. I swear my legs feel like I could run or ride my bike for hours. Don't even mention weights! I feel awesome lifting when I use my Jack3d. Started with 1/2 a scoop 3 times a week, that was for two weeks, now I am up to 1 scoop. I love it and will continue to buy it when i run out.
Good luck with Jack3d!!!