If the league has the power to suspend these guys, then they ought also to have the responsibility of providing them with a web site/hot line where they can get definitive answers about any particular substance.
There is a lot of info/resources out there. Among the problems though is that the lists change, and manufacturers 'adapt.' The maker of Jack3d doesn't list methylhexanamine as a substance, rather lists it by its more technical name, "1,3-dimethylamylamine."
After the recent rash of positives for methylhexanamine MiLB has sent a warning to clubs about Jack3d. Unfortunately a tad late for 8 or so of the kids.
Will Carrol (I know, but still) and Maury Brown have both written decent article on methylhexanamine and/or resources/policies, and are worth a look if you're interested in the subject.
Carroll
LINK; Brown
LINK.