Testosterone Supplements May Hurt Male Fertility, Study Finds05/10/13
FRIDAY, May 10 (HealthDay News) -- Testosterone supplements are
touted as a cure for low libido, but men who take them may reduce
their odds of fathering a child, new research suggests.
Many men who sought infertility treatment at two U.S. clinics
reported taking prescription testosterone supplements, according to
a new study. And in most cases their sperm counts skyrocketed after
they stopped taking the male hormone.
The study, limited to a pair of clinics in Alabama and Kansas,
looked at the years 2005 to 2011. The researchers don't know if
testosterone supplements, which continue to gain popularity, are
contributing to even more cases of infertility now. Nor is it clear
whether the hormone is harming fertility across the nation.
Still, the research suggests that testosterone spells trouble
for many American men who want to have children, said study
co-author Dr. Peter Kolettis, a professor of urology at the
University of Alabama at Birmingham. "This has become a preventable
cause of infertility."
Use of testosterone supplements -- or "T" -- is rapidly rising
in the United States, and some observers think usage will remain
inflated as more men see it as a possible cure for fatigue and
flagging sex drive. Critics, however, question whether testosterone
treatment is being prescribed to men who don't need it.
"More men are coming into [doctors'] offices asking for testosterone because they've seen the advertisements, and it looks like the fountain of youth: It will reduce fat, make them look sexier," said Dr. Bradley Anawalt, an endocrinologist and chief of medicine service at the University of Washington Medical Center in Seattle, who was not involved in the study.
But testosterone can cause side effects such as male breast
growth and blood clots. And "very few physicians are warning that
it will turn off their sperm production," Anawalt said.
Adding testosterone to the body through supplementation spurs a
process that impedes sperm production, Anawalt said. "Men
struggling with fertility should not be on testosterone," he said.
"[But] this is not something that most physicians or patients are
The study, presented Wednesday at the annual meeting of the
American Urological Association in San Diego, aimed to find out how
many infertile men take the supplements despite the risks.
The researchers examined medical records of more than 1,500 men
with an average age of 35 who sought fertility treatment at the two
Seven percent of the men were taking supplemental testosterone
prescribed by a physician. The study focused on 34 men who agreed
to stop using the hormone supplements.
Overall, the sperm counts of most patients bounced back. Average
sperm concentration in semen jumped from 1.8 million per milliliter
to 34 million per milliliter after supplemental testosterone was
But the sperm counts of six of the 34 patients didn't recover.
Testosterone treatments normally don't hurt fertility permanently,
and it's not clear if they played a role in the men's continued
infertility. The study also did not prove a direct cause-and-effect
relationship between testosterone supplements and lowered sperm
Anawalt said it typically takes between one and six months for a
man's sperm count to recover after he stops using a testosterone
Kolettis, the study co-author, said certain men should avoid
testosterone supplements. "I tell men not to take it until they're
done having their own biological children," he said.
The supplemental testosterone in question is prescription-only,
and unrelated to over-the-counter supplements marketed to increase
Data and conclusions presented at meetings should be considered
preliminary until published in a peer-reviewed medical journal.
For more about
testosterone, try the U.S. National Library of Medicine.
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