Methods

We used a freezed dried extract of Eurycoma longifolia (E) standardized to 22%

eurypeptides and 40% glycosaponins. Male subjects (N=30) were recruited from a 24-hour mountain biking event and asked to provide a saliva sample before and after each lap for measurement of cortisol and testosterone by enzyme immunoassay (Salimetrics, State College, PA). Subjects completed 4 laps (14.91 miles/lap) and provided 8 saliva samples over a 24h period. Subjects consumed 100mg of E (N = 15) or a look-alike placebo (P, N = 15) approximately 30 minutes prior to endurance exercise.

Results

Cortisol levels were 32.3% lower in E compared to P (0.552+0.665 versus 0.816+0.775 ug/dL, P < 0.05). Testosterone levels were 16.4% higher in E compared to P (86.72+40.90 versus 72.47+33.77 pg/mL, P < 0.05).

Conclusions

These results suggest that Eurycoma longifolia extract may help to maintain normal levels of cortisol (low) and testosterone (high) and thus promote an overall “anabolic” hormonal state (versus a “catabolic” state characterized by elevated cortisol and suppressed testosterone) during intense endurance exercise.