I have used a couple pre workouts in the past and out of all the only one I would recommend is MusclePharms Assault. It has been a few years since I used it but I am sure they have only improved the formula. First time I took it I worked out for four hours and I felt Euphoric for the rest of the day. I made great gains off this product and in addition it saved me from some horrendous hangovers. Whether you are looking for a great pump, hulk like energy, or something that will spare you from a hangover I highly recommend this product. Never felt a crash, mini heart attack, or sick from this product. Finally the ingredients in Assault are of high standard (No sketchy ingredients).