Sheff has a somewhat believable story

about being prescribed stuff by Victor Conte (head guy at Balco) to deal with his post surgery recovery (creams, etc.) and not taking anything heavier than that. He also only worked out with Barry a few weeks before they had a falling out (not hard to believe) and says that he didn't do anything out of the ordinary. This is backed up by Conte.

Now, I had thought that there was something else there but perhaps I am mistaken.

Alex, on the other hand, is just a total fucking liar and was the whole time.