The gateway hypothesis posits that athletes are at risk of progressing to doping if sport supplements are already used for performance enhancement. Recent research has indicated that athletes with stronger beliefs in the effectiveness of sport supplements in improving performance are more likely to use sport supplements (1). Hypothetically, therefore, if athletes’ beliefs about sports supplements influence supplement use, and if supplement use predicts doping (i.e. the gateway hypothesis), it is reasonable to suggest a relationship between beliefs about supplements and doping likelihood. However, this relationship remains untested. This study aimed to test the mediating role of sport supplement beliefs on the relationship between sport supplement use and doping likelihood.
Four hundred and eighty one competitive athletes (mean + SD: age = 19.6 ± 2.2 yrs, hour per week training = 6.3 ± 4.5, years competing = 5.9 ± 4.6) were recruited from sports clubs and asked to complete measures of sport supplement use, sport supplement beliefs and doping likelihood.
Sport supplement use was associated with sport supplement beliefs (r = 0.46, p <0.01) and doping likelihood (r = 0.14, p < 0.01), and sport supplement beliefs were correlated with doping likelihood (r = 0.22, p <0.01). Mediation analysis indicated that sport supplement beliefs significantly mediated the relationship between sport supplement use and doping likelihood (β = 0.20, 95% CI = 0.10 to 0.30), whereas sport supplement use was not directly related to doping likelihood (β = 0.04, 95% CI = -0.05 to 0.15).
The results of this study indicate sport supplement use predicts doping likelihood via sport supplement beliefs. These findings provide novel evidence to suggest that athletes using sport supplements are more likely to dope due to their belief in the effectiveness of these substances and could help further explain why athletes using sport supplements are more likely to progress to doping (i.e. gateway hypothesis).