Some have suggested that growth hormone is a wonder drug ( 16 ) that results in ripped muscle ( 17 ) and provides stamina-increasing properties ( 18 ) .
The use of human growth hormone to improve athletic performance has recently received worldwide attention .
This practice , often called sports doping , is banned by most professional sports leagues and associations , including the International Olympic Committee , Major League Baseball , and the National Football League ( 13 ) .
However , a wide range of athletes , including those from baseball ( 46 ) , cycling ( 7 , 8) , and track and field ( 5 , 9 ) , have been implicated in or have confessed to illicit growth hormone use .
The Mitchell report ( 10 ) recently identified 89 Major League Baseball players who allegedly used performance-enhancing drugs , and some of these players have subsequently admitted to using growth hormone ( 11 , 12 ) .
Part of the attraction of using growth hormone as a performance enhancer has been that its use is difficult to detect .
The World Anti-Doping Agency , whose formation stemmed from the widely publicized doping sc and al of the 1998 Tour de France ( 13 ) , first used a blood test to detect exogenous growth hormone during the 2004 Olympic Games in Athens .
Although growth hormone is reportedly used to enhance athletic performance and has been called the most anabolic substance known ( 15 ) , its efficacy for this purpose is not well established .
Exogenous growth hormone therapy in growth hormonedeficient adults ( that is , those with growth hormone deficiency due to hypothalamic or pituitary defects ) results in increased lean mass and decreased fat mass ( 19 ) , and comparable body composition changes are seen in healthy elderly adults who receive growth hormone ( 20 ) .
Some experts , however , have suggested that the strength-enhancing properties of growth hormone among healthy adults have been exaggerated ( 15 ) .
Serious side effects , including diabetes , hepatitis , and acute renal failure , may occur in athletes using high-dose growth hormone ( 21 ) .
Furthermore , the use of growth hormone for athletic enhancement is not approved by the U.S. Food and Drug Administration , and the distribution of growth hormone for this purpose is illegal in the United States ( 22 ) .
We performed a systematic review of r and omized , controlled trials to determine the effects of growth hormone therapy on athletic performance in healthy , physically fit , young adults .
Our primary aim was to evaluate the effects of growth hormone on body composition , strength , basal metabolism , and exercise capacity .
In addition , we sought to synthesize the evidence on adverse events associated with growth hormone in the healthy young and assess the quality of the published literature .
Effects of growth hormone administration on fuel oxidation and thyroid function in normal man.
In a r and omized , double-blind , placebo-controlled , cross-over study , we examined the effects of 14 days of growth hormone ( GH ) administration ( 12 IU/d subcutaneously ) on  energy expenditure ( EE ) , respiratory exchange ratio ( RER ) , and thyroid function in 14 normal adults of normal weight ( eight men and six women ) .  EE ( kcal/24 h ) was significantly elevated after GH administration ( 2,073 + /- 392 , [ GH ] , 1,900 + /- 310 , [ placebo ] , P = .01 ) . RER was significantly lowered during GH administration ( 0.73 + /- 0.04 v 0.78 + /- 0.06 , P = .02 ) , reflecting increased oxidation of lipids . Total triiodothyronine ( TT3 ) ( nmol/L ) and free T3 ( FT3 ) ( pmol/L ) increased significantly during GH ( TT3 : 1.73 + /- 0.06 [ GH ] , 1.48 + /- 0.08 [ placebo ] , P = .01 ; FT3 : 6.19 + /- 0.56 [ GH ] , 5.49 + /- 0.56 [ placebo ] , P = .01 ) . Concomitantly , an insignificant decrease in reverse T3 ( rT3 ) ( nmol/L ) was observed ( 0.07 + /- 0.01 [ GH ] , 0.15 + /- 0.01 [ placebo ] , P = .08 ) . GH caused a highly significant increase in T3/thyroxine ( T4 ) ( x 100 ) ratio ( 1.84 + /- 0.12 [ GH ] , 1.37 + /- 0.06 [ placebo ] ) . Serum thyrotropin ( TSH ) was not significantly changed by GH . No changes in total thyroxine ( TT4 ) ( nmol/L ) ( 98 + /- 6 [ GH ] , 111 + /- 8 [ placebo ] , P = .40 ) and free thyroxine ( FT4 ) ( pmol/L ) ( 17.4 + /- 1.3 [ GH ] , 18.6 + /- 1.1 [ placebo ] , P = .37 ) after 14 days of GH administration were observed . In conclusion , 2 weeks of GH administration increases EE and lipidoxidation . This finding may partly be mediated by an increase in peripheral T4 to T3 conversion
Some have suggested that growth hormone is a wonder drug ( 16 ) that results in ripped muscle ( 17 ) and provides stamina-increasing properties ( 18 ) .
The use of human growth hormone to improve athletic performance has recently received worldwide attention .
This practice , often called sports doping , is banned by most professional sports leagues and associations , including the International Olympic Committee , Major League Baseball , and the National Football League ( 13 ) .
However , a wide range of athletes , including those from baseball ( 46 ) , cycling ( 7 , 8) , and track and field ( 5 , 9 ) , have been implicated in or have confessed to illicit growth hormone use .
The Mitchell report ( 10 ) recently identified 89 Major League Baseball players who allegedly used performance-enhancing drugs , and some of these players have subsequently admitted to using growth hormone ( 11 , 12 ) .
Part of the attraction of using growth hormone as a performance enhancer has been that its use is difficult to detect .
The World Anti-Doping Agency , whose formation stemmed from the widely publicized doping sc and al of the 1998 Tour de France ( 13 ) , first used a blood test to detect exogenous growth hormone during the 2004 Olympic Games in Athens .
Although growth hormone is reportedly used to enhance athletic performance and has been called the most anabolic substance known ( 15 ) , its efficacy for this purpose is not well established .
Exogenous growth hormone therapy in growth hormonedeficient adults ( that is , those with growth hormone deficiency due to hypothalamic or pituitary defects ) results in increased lean mass and decreased fat mass ( 19 ) , and comparable body composition changes are seen in healthy elderly adults who receive growth hormone ( 20 ) .
Some experts , however , have suggested that the strength-enhancing properties of growth hormone among healthy adults have been exaggerated ( 15 ) .
Serious side effects , including diabetes , hepatitis , and acute renal failure , may occur in athletes using high-dose growth hormone ( 21 ) .
Furthermore , the use of growth hormone for athletic enhancement is not approved by the U.S. Food and Drug Administration , and the distribution of growth hormone for this purpose is illegal in the United States ( 22 ) .
We performed a systematic review of r and omized , controlled trials to determine the effects of growth hormone therapy on athletic performance in healthy , physically fit , young adults .
Our primary aim was to evaluate the effects of growth hormone on body composition , strength , basal metabolism , and exercise capacity .
In addition , we sought to synthesize the evidence on adverse events associated with growth hormone in the healthy young and assess the quality of the published literature .