Testosterone (TRT): a treatment for a diagnosis, not an upgrade

Testosterone therapy sits at an awkward intersection of real medicine and marketing. On one side, hypogonadism is a genuine clinical condition with a real treatment. On the other, “low T” has been sold to healthy middle-aged men as an anti-aging upgrade — a way to reclaim energy, libido, and muscle. The gap between those two framings is where most of the confusion, and most of the inappropriate prescribing, lives.

The honest starting point is what hypogonadism actually is. It’s not a single lab value. Diagnosis requires both consistent symptoms — low libido, erectile problems, fatigue, loss of muscle, low mood — and repeatedly low morning testosterone measured on more than one occasion, because levels are highest in the morning and swing day to day. A man with clear symptoms but normal, or even low-normal, morning testosterone usually does not have a testosterone problem, and giving him testosterone usually doesn’t fix what’s wrong.

What the evidence shows

For men who genuinely meet the diagnosis, TRT reliably raises testosterone into the normal range and can improve libido, sexual function, and some symptoms. The magnitude for things like mood and energy is more modest and more variable than the marketing implies, which is part of why the overall evidence here is graded B rather than A: the benefit is real but bounded, and it depends heavily on selecting the right patient.

The biggest recent contribution is TRAVERSE, a large randomized safety trial in hypogonadal men who were at high cardiovascular risk. It was designed to settle a decade of worry that testosterone might cause heart attacks and strokes. The result: TRT was noninferior to placebo for major adverse cardiac events. That’s genuinely reassuring — but read it precisely. It tested treatment of diagnosed hypogonadism, not enhancement in men with normal levels, and it did flag more atrial fibrillation and a few other events in the testosterone group. Safety-in-the-indicated-population is not the same as “harmless for anyone who wants it.”

The adult context

The trade-offs are predictable endocrinology, not surprises.

• Fertility suppression and testicular atrophy. Exogenous testosterone shuts down the body’s own hormonal signaling, which drops sperm production and shrinks the testes. For a man who wants children in the foreseeable future, this is a serious consideration, and guidelines advise against starting TRT in that situation.
• Erythrocytosis. Testosterone thickens the blood by raising hematocrit, more so in older men. It needs monitoring, and therapy isn’t started when hematocrit is already high.
• Monitoring generally. Testosterone level, hematocrit, and prostate assessment on a schedule — TRT is an ongoing relationship, not a prescription you set and forget.

Which brings the whole thing back to selection. The single most common mistake is treating “low-normal testosterone with fatigue” as a testosterone problem. Fatigue in a normal-range man is far more often about sleep, training, body composition, stress, alcohol, or an unrelated medical issue — the actual foundations — and TRT there means accepting fertility suppression and lifelong monitoring to chase a fix that testosterone probably won’t deliver.

The honest bottom line: TRT is appropriate, useful, and — per TRAVERSE — reasonably safe for diagnosed hypogonadism. It is not an anti-aging tool for men with normal levels, and the diagnosis has to come before the prescription. Both belong in a clinician’s hands.