I have had no problems in the past carrying opened bottles of prohormones, various supplements, and protein powders in my checked baggage. Funny story, the last time I visited my family I was on a cycle of anabolics and when I was visiting I lost my wallet with all of my identification and credit cards. So, when I tried to get on the plane to fly back home I was interrogated exstensively, searched and scrutinized about everything I had, and the like. It probably didn't help that I had a gnarley black eye and half of my face was covered in road rash from a bicycle accident that looked more like I got into a scuffle. And they didn't take my prohormones or other supplements which I thought they might since the bottles were opened and it could have been anything in there. This was a domestic flight FWIW.