Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., Bendavid, E., Saynia, O., Salpeter, S. R., Garber, A. M., & Hoffman, A. R. (2008). Systematic review: The effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), on line version.

This review evaluated published evidence about the effects of growth hormone on athletic performance in physically fit, young individuals. The MEDLINE, EMBASE, SPORTDiscus, and Cochrane Collaboration databases were searched for English-language studies published between January 1966 and October 2007. Studies were selected according to the following criteria: Randomized, controlled trials that compared growth hormone treatment with no growth hormone treatment in community-dwelling healthy participants between 13 and 45 years of age.

Forty-four articles describing 27 study samples met inclusion criteria. Ss (N = 303) received growth hormone, representing 13.3 person-years of treatment. Participants were young, lean, and physically fit. Growth hormone dosage and treatment duration varied. Lean body mass increased in growth hormone Ss compared with Ss who did not receive growth hormone, but strength and exercise capacity did not improve. Lactate levels during exercise were significantly higher in growth-hormone Ss in two of three studies. Daily metabolic rate was higher in growth hormone-treated Ss. Physiological factors associated with endurance activities were not altered/improved in growth-hormone Ss. Growth hormone–treated Ss more frequently experienced soft tissue edema and fatigue than did those not treated with growth hormone.

Few studies evaluated athletic performance. Growth hormone protocols in the studies may not reflect real-world doses and regimens.

Implication. The claim that growth hormone enhances physical performance are not supported by the scientific literature. Although the limited available evidence suggests that growth hormone increases lean body mass, it may not improve strength; in addition, it may worsen exercise capacity and increase adverse events. [The restrictive nature of study selection meant that some valid studies reported in refereed publications were not considered.

Reactions in the Media

Associated Press. March 17, 2008). Study: HGH may worsen performance. SI.com. [https://sportsillustrated.cnn.com/2008/baseball/mlb/specials/spring_training/2008/03/17/growth.hormone.ap/index.html]

"But the new research has some limitations and sheds no light on long-term use of HGH. The scientists note their analysis included few studies that measured performance. The tests also probably don't reflect the dose and frequency practiced by athletes illegally using the hormone. Experiments like that aren't likely to be conducted.

Consequently, those in the field have to depend on such reviews or "what we hear on the ground," he added."

[This reaction attempted to put the best "spin" on WADA's banning of this substance. Indeed, it is likely that excessive doses of the substance would increase the likelihood of health risks, the exhibition of those risks depending upon the individual and dose frequency and extent. But, with no studies suggesting a hint of performance improvement and even performance detriment, the tilt is toward this being a benign substance for sporting enhancement. That athletes use it does not imply it is beneficial. It is equally plausible that athletes purchase/use HGH because of myth-oriented propaganda believing it to be useful because "someone told me it would help" or "everyone else is using it so it must work". Athletes who are users support an industry that essentially sells a modern-day version of snake oil.

Of greater concern is the reliance of WADA on rumors ("what we hear on the ground") for determining anti-doping policy. That lack of policy rigor undermines the credibility of the organization still further.]

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