Like everyone said its the 1,3 that causes ED.. pre workous like jack3d are the worst pre workout you can ever take, lets put the health risk aside.. The only damn thing these stimulant pre workouts do is get you a buzz, thats all they do.., They dont do a damn thing in increasing performance, they actually decrease blood flow to the muscle so you get less nutrient during your workouts, less muscle pump which is counterproductive if you want to build muscle and increase strength..The only reason ppl take these crap is to get a buzz thinking the shit is working, not to mention they are filled with cheap and dangerous ingredients.. I would go with a respectable company like Gaspari, AST ON etc..