I don't think they can detect minoxidil in the Urine or Blood. But I know for a fact Propecia is banned in professional sports because it can be used to mask the use of steroids. Which personally I think is VERY harsh. Basically a sportsman has to make a decision of his hair or carreer in the professional arena. It can can definately be detected in the urine and blood. As for minoxidil, im not so sure sorry. But my guess is no. At lesat not in the Urine. Possibly the blood or hair.