Common. Measurable. Treatable. Low testosterone.

Testosterone is highest in the morning and falls through the day, so an afternoon sample can read low in a man who is fine and normal in a man who is not. A standard panel usually measures total testosterone and nothing else, but much of it is bound up and unavailable to your body. And “normal” is a wide range built from a population, not from you.

Total testosterone. Free testosterone. SHBG. Prolactin. Oestrogen. PSA. Hb and haematocrit. Seven markers, one draw.

No, and the difference is the whole point. Anabolic steroid use means large doses that push levels far above normal, usually without a diagnosis. Testosterone therapy means restoring a measured deficiency back to a normal range, at a dose your doctor sets from your blood results.

If you have prostate or breast cancer, untreated severe sleep apnoea, an already raised red cell count, or if you are trying to conceive. And if your blood tests do not support the diagnosis.

A lot of men have thought about it. Every risk is managed by measuring something and then acting on it, and if you buy it yourself nobody measures anything. Testosterone is a Schedule 5 medicine in South Africa - it is scheduled because it needs a doctor.