Growth Hormones Flex Little Muscle
Athletes Who Take Human Growth Hormones for Competitive Edge Derive Little Benefit, Studies Show
March 18, 2008 -- Athletes who risk their careers and reputations by taking
human growth hormones may be getting little in return, a new research review
Combined results from 27 studies did not support the claim that taking human
growth hormones boosts athletic performance.
Short-term use of growth hormones was associated with increases in lean body
mass, but not improvements in strength.
And there was even some suggestion that human growth hormone worsened
The studies were small and of short duration, with the longest lasting just
Larger, longer studies are needed to conclusively determine whether growth
hormone improves athletic performance, and if so, at what cost, researcher Hau
Liu, MD, MPH, tells WebMD.
"Based on the current literature, we found no evidence that human growth
hormones improved exercise capacity or athletic performance," he says.
Human Growth Hormone Studies
Human growth hormone is produced naturally in the body, and is essential for
growth and development. A synthetic version, available since 1985, is used to
treat growth hormone deficiency and other medical conditions.
Athletes take it in the belief that growth hormones will improve their
performance and help them recover more quickly from injury.
But they are acting on faith, because the research doesn't prove these
claims, Liu says.
The studies reviewed by Liu and colleagues from California’s Santa Clara
Valley Medical Center and Stanford University included 303 physically fit
healthy people -- mostly young men -- given growth hormone treatment either by
injection or infusion.
The participants were followed for one month to just under three months to
determine if the growth hormone affected body composition, strength,
metabolism, and exercise capacity.
Although growth hormone use did seem to lead to increases in lean body mass,
it did not appear to improve muscle strength.
And Liu says two of three studies examining exercise performance showed
growth-hormone-treated patients had higher lactate levels than untreated
control subjects, which could be indicative of diminished exercise capacity.
Growth-hormone-treated participants also reported more fatigue.
The study appears in the May 20 issue of the Annals of Internal
Medicine, but it was released online today.
"More research, including identification and evaluation of the
real-world growth hormone doping protocols, is warranted to definitively
determine the effects of growth hormone on athletic performance," they
Spotlight on Performance-Enhancing Drugs
Like anabolic steroids, growth hormone is banned by the World- and U.S.
Anti-Doping Agency, the Olympic Committee, and most major and amateur sports
While steroid use can be detected though a simple urine test, this is not
the case with growth hormones.
As a result, it is not at all clear how widespread growth hormone use is
among student and professional athletes.
"The estimates have been from just about everyone to almost nobody,"
U.S. Anti-Doping Agency senior managing director Larry Bowers, PhD, tells
WebMD. "We just don't know."