Steroids used for athletics have two functions: androgenic and anabolic. Androgenic signifies that it increases male sexual characteristics, and anabolic that it builds muscle. Steroids are essentially testosterone mimics with qualities that athletes want, such as longer half-life, more potent anabolic effects, and so on.
How does testosterone itself perform in that regard? Pretty well.
In a study of testosterone replacement therapy in hypogonadal men – that is, they had low T – they had an average 20% gain in muscle mass over 6 months. In other words, huge. Even better, they also had a loss of fat mass of 11%.
So, maybe testoserone’s anabolic affects have an upper limit, that is, what about supraphysiologic doses in men who already have normal T? Yes, that works too: The Effects of Supraphysiologic Doses of Testosterone on Muscle Size and Strength in Normal Men. In this study, young men were given high doses of T, a 600 mg injection once weekly. They also did resistance training 3 days a week, and ate a diet with enough protein to support optimal muscle growth, 1.5 grams per kilogram body weight, or about 0.7 grams/lb.
Results: those in the T + exercise group gained 6 kg, or over 13 pounds, over 12 weeks, and it was all muscle. But to show the power of T: even those who did not lift weights gained 3.2 kg of muscle.
One lesson here is that if you’re having difficulties in the gym with putting on muscle, a test for your T level would seem to be in order, whether you’re young or old. Should your T levels be suboptimal, then comes the harder part: convincing your doctor to prescribe T for you. Granted, if you’re youngish and in good health, some other strategies may work for increasing T, such as fat loss, ensuring adequate zinc in your system, and certain posture exercises, as shown here. Weightlifting itself, as well as a HIT exercise program, also improve T levels, so keep at it.