From underwear ads featuring young muscular models to the latest superhero film starring an actor with a newly buff physique, the pressure to look a particular way or attain a certain level of fitness can be immense.
And for those guys who may feel they haven’t reached (or are no longer at) their peak potential, there are plenty of products marketed to help them reach that goal. These can include drugs or hormonal supplements to help gain bigger muscles, increase energy levels, or improve their libido.
However, what some men may not know is that several of these chemical and hormonal supplements can also increase their risk of infertility.
As Dr. Brian Levine, founding partner and practice director of CCRM New York, puts it, “taking testosterone is almost male contraception.”
The use of testosterone or anabolic steroids to gain muscles mass, and thus appear more fertile, while actually increasing one’s likelihood of infertility, is now known as the Mossman-Pacey paradox, named after the two researchers who first described it, as the BBC and other outlets recently reported.
It pits two different points of a man’s search for a mate: the short-term gains of appearing more attractive to females while enduring potential long-term damages to their ability to reproduce.
That’s particularly about the type of steroids used to grow muscles to nearly Herculean size. But it’s also in the small daily doses of products meant to increase energy and improve libido.
Dr. Katherine McKnight, a reproductive endocrinology and infertility specialist at Houston Methodist and CCRM Houston, says she sees a large population of couples with male infertility solely due to testosterone use, as high doses of testosterone decrease a man’s sperm count significantly.
“There is a large focus in men’s health today on combating fatigue and increasing energy and libido,” she told Healthline. “Unfortunately, hormonal medications, specifically testosterone and its derivatives, are used to manage these symptoms.”
While some effects of these medications that alter testosterone can be reversed, experts warn it’s better to avoid anything that messes with your body’s testosterone levels because it can develop a tolerance.
Basically, the more the brain senses testosterone in the blood, the less it signals for the testes to make on their own.
Paul Jenkins, sports coach and founder of the supplement company DNA Lean, has two decades worth of experience working with athletes, namely amateur and professional competitive bodybuilders, “of which all have used steroids.”
Balding is another common side effect of testosterone use, which is why so many bodybuilders shave their heads.
Jenkins says when external testosterone is introduced into a man’s body, it breaks the body’s natural cycle, causing the testes to stop their production of natural testosterone, resulting in testicular atrophy.
“As you can imagine, shrunken testicles are largely infertile,” Jenkins told Healthline. “When testosterone treatments are ceased, the testes will be shut down and testosterone levels will plummet. This results in erectile dysfunction and infertility, along with a myriad of other symptoms.”