zinc can and does cause stomach aches if it's taken on an empty stomach. (similar to taking a heavy duty multivit on an empty stomach.) this is probably your problem. if it's bloating you feel, then it's probably not the zma but your cheap ass protein, or too much carbs, or not getting enough pussy. for me, zma keeps me from sleeping. basically, everything keeps me from sleeping, but for some retarded reason, zma compounds it.