Bodybuilders who use steroids may suffer long-term testicle damage, and it could affect their fertility

• Testicle damage lasted for years after participants quit steroids.
• Misusing steroids may lead to shrinking testicles and an increased risk of prostate cancer.
• Professional athletes aren't the only people using steroids to bulk up.

Bulking up with steroids was linked to damaged testicles later in life, a small study finds.

Anabolic steroids -synthetic or human-made testosterone - are prescribed to treat late puberty or diseases that cause muscle loss, according to the National Institute of Drug Abuse.

But these steroids are also misused to enhance workout performance - and the doses are 10 to 100 times higher than the dose to treat a legitimate medical problem.

"It has been unclear whether illicit use of anabolic steroids caused a long-lasting or even persistent impairment of the testosterone production in the testicles," Dr. Jon Rasmussen, study author and a scientist at Rigshospitalet, told CNN.

The study found that former anabolic steroid users had testicle dysfunction two and a half years after quitting steroids.

"Long-term use of anabolic steroids can suppress testicular function, and even when these men stopped using anabolic steroids, the recovery of testicular function can be incomplete or recovery may not occur," Dr. Shalender Bhasin, a Harvard Medical School professor of medicine who was not involved in the study, told CNN.

Anabolic steroids can alter hormones and affect bodily functions

The researchers studied 132 men that were either nonusers, current users, or former users of anabolic steroids. They assessed testicle function by looking at concentrations of hormone serum insulin-like factor 3 (INSL3) among the participants.

The study found that men who used anabolic steroids had lower amounts of (INSL3). This can lead to cascading effects like halting testosterone production which, in turn, impairs fertility, according to Rasmussen.

Beyond the study, misuse of anabolic steroids among men has been linked to shrinking testicles, a drop in sperm count, and a higher risk of prostate cancer. For women, it can lead to excess body hair or a deepened voice.

Steroid abuse isn't just limited to professional athletes

But Bhasin cautioned anabolic steroid misuse isn't just a niche problem reserved for professional, cheating athletes.

"The real story is that the vast majority of anabolic steroid users - more than 90% - are not elite athletes. In fact, they are not athletes at all. They are recreational bodybuilders who use these compounds to look leaner and more muscular," Bhasin told CNN.

Other research says misusing steroids are linked to other risky activities like drinking and driving, or using other illicit drugs.

Professional athlete or not, Rasmussen had clear advice to anyone thinking about using steroids: "Don't even consider it. Use of anabolic steroids can cause persistent adverse effects on several organs in the body and could even be lethal."