Researchers led by Dr Keith Jarvi, MD, professor of surgery at the University of Toronto and chief of urology at Toronto's Mount Sinai Hospital, found that giving testosterone therapy could lead to fertility problems in a small number of men, though the problem disappears once they stop taking the supplements.
The researchers examined medical record of more than 4,400 men who had been evaluated for infertility at the Mount Sinai Hospital between 2008 and 2012. Around 56 men were taking testosterone supplements at the time, either to increase their sex drive or for muscle-building, and the researchers found that it lowered the levels of the hormone in the testicles, leading to lower fertility.
The researchers added that many doctors were not aware that the supplements could lead to lower infertility and prescribed them to their patients.
"Every now and then, we'd see a young male patient coming through who'd be on testosterone. Sometimes, they were on it for muscle-building purposes or for a decreased sex drive. Quite often they'd be completely unaware that this would have a negative effect on sperm production. A number of our colleagues aren't aware of that. They may use testosterone in an older man when fertility concerns aren't present. But fertility may still be a concern for man who's 30 or 40, but it's not in front of the mind of the physician", Dr Jarvi told the Urology Times.