Is TRT safe long term?

For men with properly diagnosed low testosterone, current evidence suggests TRT is reasonably safe long term — but it's a medical therapy that needs monitoring, not a shortcut for already-normal levels.

The biggest question about testosterone replacement therapy has always been the heart. For years, conflicting studies left men unsure whether TRT raised cardiovascular risk. That changed with TRAVERSE, published in the New England Journal of Medicine in 2023 — the largest trial to date, following more than 5,000 men with low testosterone and existing heart risk for around two years. It found testosterone therapy did not increase the rate of major cardiac events compared with placebo. That's reassuring, and it's why TRT is prescribed with more confidence today.

But “reasonably safe” isn't the same as “risk-free.” Long-term TRT can thicken the blood by raising your haematocrit, which is why regular blood tests matter. It commonly reduces fertility by shutting down your own sperm production — a serious consideration if you still want children. It also requires ongoing prostate monitoring. And because TRT suppresses your natural testosterone, it usually becomes a lifelong commitment; coming off it can leave you worse than before until your own production recovers, which can take months.

There's also a misuse problem worth naming. TRT is a legitimate treatment for diagnosed low testosterone under medical supervision — it is not a performance enhancer or an anti-ageing fix for men whose levels are already normal. Used that way, the risk-to-benefit balance shifts the wrong way and the TRT side effects start to outweigh any benefit.

What to do: if you have genuine symptoms and two low morning blood tests, TRT can be life-changing — but do it properly. That means a proper diagnosis, regular monitoring of blood count, PSA and hormones, and an honest conversation about fertility before you start. Many men should also try optimising sleep, body fat, and training first, since that's free and reversible.