yes they do. I have not used GH or slin, but based on my extensive reading, the evidence is there that if you do your research you will grow like a mofo, although it is too bad you cannot us AS because of the testing. Are you d1 players tested in the offseason as well? If not, and you can start immediately, look to AS that you can use in conjuction with the GH slin that have short detection half lives. I'll go ahead at let the experienced guys chime in now.