Human growth hormone doesn't work when it comes to enhancing athletic performance, according to an extensive review of studies by a team of 11 Stanford University researchers, Stanford announced Monday afternoon.

The use of human growth hormone (HGH) by professional athletes to enhance performance has been the subject of a national investigation and Congressional hearings for baseball players.

But the Stanford researchers say HGH doesn't improve athletic performance and may in fact reduce an athlete's stamina.

In the study, released Monday afternoon, 11 Stanford researchers reviewed 44 research articles on HGH published in recent years.

The studies covered 303 participants, mostly young (median age 27) men with lean body mass who were physically fit.

After poring over the data, the Stanford researchers concluded that the benefits of HGH are overblown.

"Growth hormone is reported to be extensively used for illicit enhancement of athletic performance, both for its anabolic and endurance effects," the authors wrote.

"However, our review of the published literature suggests that while growth hormone may alter body composition it has minimal effect on key athletic performance outcomes and may, in fact, be associated with worsened exercise capacity."

The study concluded that HGH, popular with body builders, does alter body mass but "it did not result in gains in biceps and quadriceps strength."

In one key study measuring athletic endurance, two of seven cyclists could not complete a scheduled exercise regime after receiving growth hormone but could after taking a placebo instead. Two studies associated growth hormone with "decreased exercise stamina and physical exhaustion."

The use of steroids, HGH and blood doping has tainted the Olympics, the Tour de France bicycle race and major-league baseball.

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