Do you insist on rising at five to run each morning, even when your back is aching, black ice coats the streets, and your wife beseeches you to stay in bed? Do you only feel good when you’re training for triathlons? Is eating merely a way to replenish for the next race? Then you, my Spandex-clad friend, may have an exercise addiction.
But if you want to have children, there's one downside to TRT you should know about. It gives you back your sex life, but it might also reduce your ability to father children as long as you're on it.
"Testosterone replacement therapy has a profound impact on a man's reproductive potential," says urologist Michael Eisenberg, MD. He's director of male reproductive medicine and surgery at Stanford Hospital and Clinics in Palo Alto, Calif.
Testosterone plays an important role in making sperm.
Eisenberg describes the relationship between testosterone and sperm production as part of a "feedback loop." Here's how the system works.
Your brain makes special hormones, called gonadotropin-releasing hormones (GnRH). These hormones signal the testes to make more testosterone, vital for a healthy sperm count.
When you're getting testosterone replacement therapy, testosterone is added into the bloodstream by patches, gels, or other treatment methods.
Your brain interprets this rise in testosterone levels as a sign that you now have enough testosterone. So it stops sending signals to the testes to make more testosterone. But when your testes don't make more testosterone, your sperm production goes down.
"If you have any kind of reproductive goal, you should not be using TRT," says Eisenberg.
Endocrinologist Spyros Mezitis, MD, PhD, agrees. "You want to increase the patient's own testosterone production in order to get an appropriate sperm sample for pregnancy," says Mezitis, who practices at Lenox Hill Hospital in New York City. "When testosterone comes from the outside, it suppresses the body's production of sperm."