“I see people who've been doing things in the gym and they've never been told that it can shut off your own production and it can also irreversibly lower your sperm count,” says Roked. “These are all quite serious issues that even though they may be rare if it happened to you it would cause a big impact on your life, so I'd say it's always best to do things with a specialist, but also for anyone it's not a great idea to take things that aren't needed."
So what is this Big T, anyway? Derived from cholesterol, testosterone is a steroid hormone—called an androgen—that causes the development and maintenance of masculine characteristics. It's mainly secreted by the testicles in males, although the adrenal cortex and ovaries in females also secrete testosterone—though only about one-tenth the amount as in healthy males.
Testosterone levels generally peak during adolescence and early adulthood. As you get older, your testosterone level gradually declines — typically about 1 percent a year after age 30 or 40. It is important to determine in older men if a low testosterone level is simply due to the decline of normal aging or if it is due to a disease (hypogonadism).