Can TRT make you infertile?

Yes — testosterone replacement therapy commonly reduces fertility, and in some men it can stop sperm production almost entirely. It's one of the most important things to understand before starting.

The reason is a feedback loop. When you take external testosterone, your brain senses there's plenty and switches off the signals (LH and FSH) that tell your testes to make their own testosterone and sperm. Sperm production depends on those signals and on very high testosterone levels inside the testes specifically — which, paradoxically, TRT lowers. The result is that many men on TRT see their sperm count drop sharply, sometimes to zero.

The good news is that this is usually reversible: after stopping, fertility often recovers over several months to a year or more — though not always fully, especially after long-term use. For men who want to protect fertility while treating low testosterone, doctors have options: medications like hCG, clomiphene, or enclomiphene that raise testosterone without shutting down sperm production, or banking sperm beforehand.

What to do: if you might want children — now or later — raise fertility before starting TRT, not after. Ask your doctor about fertility-sparing alternatives, and consider sperm banking as insurance. TRT can be life-changing for the right man, but going in informed about the fertility trade-off is essential.