Capsaicin analog supplementation is not effective to improve 10-km running time-trial performance in amateur athletes: a randomized, crossover, double-blind and placebo-controlled study

Background: To investigate the acute effects of a capsaicin analogue supplement on 10-km time trial performance and physiological responses in amateur athletes. Methods: Twenty-one participants (age = 29.3 ± 5.5 years), completed two randomized, double-blind trials: capsaicin analogue condition [Capsiate (CAP) = 24 mg] or a placebo condition. The participants consumed two doses of 12 mg of capsaicin or placebo capsule 45 minutes before and immediately at the start of each trial. The time required to complete 10-km, lactate concentration, maximum heart rate (HR peak ), and rating of perceived exertion (RPE) were recorded.  Results: 10-km time-trial performance (CAP = 45.07 ± 6.41 min vs. placebo = 45.13 ± 6.73, P = 0.828) was not statistically significant different between conditions. No statistically significant differences between conditions were detected for lactate concentration ( P = 0.507), HR peak ( P = 0.897) and RPE ( P = 0.517).  Conclusion: Two doses of 12 mg Capsaicin analogue supplementation did not improve performance and physiological responses in a 10-km running time-trial in amateur athletes.