One drawback to Brennan’s study is that, unlike Kouri’s, there was evidence of attempted deception. Several people had to be excluded from the non-users’ group because they were either definitely on steroids (they failed the urine test), or probably on steroids (in the researchers’ words, they had “implausibly high muscularity and low body fat despite denial of AAS use”). However, even if a couple of users slipped in, they probably didn’t skew the data too much. The sample size for nonusers was big enough (131 people) that a few bad apples wouldn’t spoil the whole bunch, and the researchers were excluding suspiciously jacked people anyways, so if a few users did slip in, they apparently weren’t swole enough to raise any red flags.
This is the scenario: a guy, say age 21, becomes serious about gaining muscle. He’s 5′ 10″, 7″ wrists, 9″ ankles, average genetics for muscle size-and-proportioned. He’s played sports, but never done more than an occasional resistance workout. Now, he begins a good training-eating-and-resting program. With his genetics, he has the potential for naturally gaining 45 pounds of lean mass if he stays consistent with progressive training/proper eating for a continuous 3 to 4 years.
But, about three months after beginning his training, he starts taking steroids. He does three steroid cycles in the following 18 months, and includes proper post-cycle therapy. That entire time, he’s continuing to consistently train and eat properly. Before the end of two years, he’s gained 45 pounds of lean mass (which with steroids, by the way, is not necessarily typical but neither improbable). At that point, he permanently quits using steroids, but he does continue properly training and eating for another two years. At the end of four years, he carries the same 45 pounds of lean mass.