My DS will be a member of the CO 2018, and I have a question about supplements. He plays baseball and many players take GNC products, like shakes and Creatine powders. I told my son he wasn't allowed to take anything and I got the "Mom" look. Does anyone on this forum know if there is a listing somewhere of banned supplements or supplements that can give false positive results on tests? I am just assuming all supplements would be banned but I want to give him correct, factual information that isn't just Mom-based. I don't want some question raised on R Day just because he drank GNC shakes during baseball season. Thank you!