TRT: the pros and cons, honestly

Testosterone replacement therapy is prescribed for men with hypogonadism, clinically low testosterone confirmed by blood testing, together with symptoms. That qualifier does most of the work in this article, because it is the thing most often skipped.

What the big trial found

TRAVERSE was designed to answer the cardiovascular safety question directly. It enrolled middle-aged and older men with documented hypogonadism who either had cardiovascular disease or were at high risk of it: the population where the concern was greatest.

The primary result: major adverse cardiovascular events occurred in 7.0% of men on testosterone against 7.3% on placebo, a hazard ratio of 0.96. Testosterone was not associated with increased cardiovascular risk in this group.

This was a genuine change in the evidence base, and it prompted a regulatory one. In February 2025 the FDA updated testosterone product labelling, removing the boxed-warning language about increased cardiovascular risk while keeping existing restrictions around age-related use.

What the same trial also found

This is the part that gets left out of the marketing, and it comes from the same dataset:

• Higher rates of non-fatal cardiac arrhythmias in the testosterone group.
• Higher rates of venous thromboembolism, blood clots.
• Higher rates of fractures, which was unexpected and remains under investigation.

So the honest summary is not “TRT is safe.” It is: in men with confirmed hypogonadism, testosterone did not raise the risk of heart attack and stroke, and did raise some other risks. Both halves of that sentence come from the same trial.

The realistic benefits

For men who are genuinely deficient, treatment can improve sexual desire and function, energy, mood, bone mineral density, and body composition, more lean mass and less fat mass.

Two caveats worth holding on to. Benefits are largest in men who were actually deficient, and shrink toward nothing as baseline levels approach normal. And in the sexual-function domain specifically, TRT is not a treatment for erectile dysfunction in men with normal testosterone; if the levels are normal, this is not the answer.

The other trade-offs

Fertility. Exogenous testosterone suppresses the body’s own production and can substantially reduce sperm count, sometimes lastingly. If you may want children, raise this before starting, not after. Alternative approaches exist that do not carry the same effect.

Testicular volume typically decreases.

Red blood cell count commonly rises and requires monitoring; it is one of the main reasons for regular bloods.

Prostate monitoring is standard practice during treatment.

It is generally lifelong. Natural production does not simply resume on stopping, and symptoms usually return.

The diagnosis is the whole thing

Testosterone falls gradually with age in most men. That decline is not by itself hypogonadism, and treating a normal age-related level is not what the evidence above supports.

A proper diagnosis needs at least two morning blood samples on separate days, because levels vary substantially through the day, along with related hormone tests to establish where the problem originates and to rule out other causes of the same symptoms, thyroid disease, sleep apnoea, depression and iron overload all produce overlapping presentations and have entirely different treatments.

A service that prescribes testosterone without pre-treatment bloods, or without a plan for ongoing monitoring, is not practising to any recognised standard. Testosterone is a Schedule III controlled substance in the United States, which is a reasonable proxy for how seriously it should be handled.

Who it suits

Reasonable: men with symptoms plus confirmed low testosterone on repeat testing, who understand the fertility implications and will attend monitoring.

Not reasonable: men with normal levels seeking a performance or physique effect, men who want children in the near future, men with untreated sleep apnoea or an active prostate concern, and anyone offered it without blood work.