depends on the test. If they're doing a simple panel test, say a state or federal probation urine test, they're most likely going to check for pot, coke, opiates, and the obvious. If its a pre-employment screening, I've heard of a computer guy getting the results of his test showing the creatine he was supplementing...but that's a really specific more expensive test. So, the answer is it depends who's testing you and how much they want to know.