Older men who use testosterone gel may see small improvements in their
muscle-to-fat ratio but are unlikely to glean any benefits in flexibility,
endurance and general ability to get around, new research suggests.
Men participating in the study had low to normal testosterone levels, were at
least 60 years old and were functioning at a relatively high level to begin
with. It's still unclear how long-term use of testosterone might affect frailer
and more disease-prone elderly men, researchers noted.
"There may be specific populations of men for whom testosterone
supplementation or replacement may be beneficial," said lead author Dr Kerry
Hildreth, from the University of Colorado School of Medicine in Aurora.
"But it's really not clear that in otherwise healthy, functional men in that
low-normal physiologic range that using testosterone either alone or in
combination with exercise added much."
The new findings, she said, suggest that testosterone "is widely used in
people where it really may not be appropriate or may not provide the benefits
that people think it's going to."
Abbott donated the testosterone gel used in the study, Androgel. The gel is
approved by the US Food and Drug Administration for men who make too little
testosterone on their own, a condition called hypogonadism.
Because testosterone levels decline naturally as men age, some researchers
have wondered if treating older, healthy men with the hormone could help slow
changes in body composition and loss of strength.
To try to answer that question, Hildreth and her colleagues randomly assigned
167 older men to use testosterone or a hormone-free placebo gel each day and to
do strength-training three times a week or not.
Use of testosterone was tied to a two-pound decrease in fat mass and a
two-pound increase in muscle mass, the study team reported in The Journal of
Clinical Endocrinology & Metabolism.
Men who weren't told to exercise also saw improvements in upper body strength
during a year of testosterone use, compared to placebo gel users.
Exercise alone led to improvements in body composition - but testosterone and
strength training did not appear to have an additive benefit, the researchers
And with or without an exercise programme, testosterone gel did not improve
men's daily functioning in tasks like climbing stairs or getting up from a
Studies have come to contradictory conclusions on the effect of extra
testosterone on men's health and physical abilities, Hildreth's team noted.
"A number of studies have shown consistent improvements in body composition
but they don't seem to translate into significant improvements in function,"
Some research has suggested that although testosterone may help improve
muscle strength in frail, elderly men, the effects don't last after treatment
AbbVie, a spinoff from Abbott that markets Androgel in the US, was not able
to not provide a comment before press time. Men in the current study seemed to
tolerate testosterone well, Hildreth noted.
But there are still long-term concerns about side effects, such as abnormal
blood counts and elevated prostate specific antigen levels."People should be
careful about using it," she said.