Introduction: GH is widely abused by athletes for its anabolic and lipolytic properties. As the tests for detecting GH abuse develop further, it is possible that athletes will exploit IGF1 as an alternative or additional doping agent. There is currently no evidence to suggest that IGF1 administration improves athletic performance.
Objectives: To determine the effects of rhIGF1/rhIGFBP3 administration on body composition and physical fitness in recreational athletes. This study was part of a randomised, double-blind, placebo-controlled trial studying detection methods for IGF1 abuse.
Methods: The study received approval from the local ethics committee. Fifty-six recreational athletes (age 1830 years, 30 males, 26 females) were randomly assigned to receive placebo, low dose rhIGF1/rhIGFBP3 complex (30 mg/day) or high dose rhIGF1/rhIGFBP3 complex (60 mg/day). Treatment was self-administered by s.c. injection for 28 consecutive days. Body composition (assessed by dual energy X-ray absorptiometry) and cardiorespiratory fitness, measured in terms of maximal oxygen uptake (VO2 max), were assessed before and immediately after treatment. Data from subjects in low and high dose treatment groups were combined and intra-individual changes were analysed using paired t-tests.
Results: There were no significant changes in body fat percentage or lean body mass in women or men after administration of rhIGF1/rhIGFBP3 complex. In both women and men, there were significant increases in VO2 max after treatment (P=0.013 women, P=0.046 men, P=0.001 men and women combined). In women, the mean increase in VO2 max was 4.2±1.5 ml/min per kg, relative increase 10.5±3.8%. In men, the mean increase in VO2 max was 3.0±1.5 ml/min per kg, relative increase 7.9±3.6%. No significant changes in VO2 max were observed in the placebo group.
Conclusions: The administration of rhIGF1/rhIGFBP3 for 28 days improves aerobic performance in recreational athletes although it has no significant effect on body composition.