More athletes are taking human growth hormone (HGH) with no scientific evidence to support its efficacy in improving performance. In a small Australian study involving 64 adult recreational athletes, some subjects were given HGH while others received a placebo. The study was randomized and double-blind. The researchers found that participants who believed they were taking growth hormone felt that their performance was improving—and actually did experience improvement—even when they were taking a placebo. All subjects in the study experienced a small performance boost, typically between 1% and 2%.
“Among those who wrongly thought that they received growth hormone, the performance enhancement was between 3% and 5%,” Dr. Kenneth Ho from the Garvan Institute of Medical Research in Sydney, Australia, told Reuters News. “This phenomenon was far greater in men than in women.”
The study results were announced at the Endocrine Society’s annual meeting in San Francisco in June 2008.