Abstract / Summary
Capsaicin analogues have been proposed as potential ergogenic aids, but their acute effects on athletic performance remain inconsistent. This study aimed to evaluate the effects of acute capsaicin analogue intake on exercise performance using a three-level meta-analysis.
PubMed, Web of Science, Scopus, SPORTDiscus, and the Cochrane Library were searched up to April 1, 2025. Randomized controlled trials examining acute oral capsaicin analogue intake in healthy adults were included. Outcomes were classified into strength, power, muscular endurance, and aerobic capacity. Hedges' g was calculated using a three-level random-effects model.
Twenty-one randomized crossover trials with 67 effect sizes were included. Acute capsaicin analogue intake significantly improved overall athletic performance compared with placebo (g = 0.20, 95% CI [0.07, 0.33], p < 0.01). Subgroup analyses showed significant effects on power (g = 0.39) and muscular endurance (g = 0.25), but not on strength or aerobic capacity. Phenylcapsaicin showed the largest effect, and benefits were more evident in trained participants. Dose-response analysis suggested a nonlinear pattern, with low-to-moderate doses showing more stable benefits.
Acute capsaicin analogue intake may produce small but significant improvements in athletic performance, particularly in power and muscular endurance. However, due to heterogeneity, publication bias, and very low certainty of evidence, these findings should be interpreted cautiously.