Hirsch K.R., Smith-Ryan A.E., Roelofs E.J., Trexler E.T., Mock M.G. Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation. J Diet Suppl. 2017;14(1):42–53.
Rationale
Cordyceps militaris extracts have long been advertised in sports nutrition as an ergogenic aid raising aerobic performance and endurance, yet few controlled human studies have assessed the effect across several standard physiological measures at once. The aim was to test whether a C. militaris-containing mushroom blend affects VO2max, time to exhaustion (TTE), ventilatory threshold (VT) and power measures on a cycle ergometer — after 1 week and after 3 weeks.
Methods
Design — randomized double-blind placebo-controlled with repeated measures. Participants — 28 healthy young adults (mean ± SD: age 22.7±4.1 years, height 175.4±8.7 cm, body mass 71.6±12.0 kg), recruited in the university lab (Applied Physiology Lab, UNC Chapel Hill). The active arm took 4 g/day of a mushroom blend containing Cordyceps militaris; control — maltodextrin in identical capsules. All took the product for 1 week; a subgroup of 10 volunteers continued for 2 more weeks. Testing: a maximal stepwise cycle-ergometer test with gas analysis (VO2max, TTE, VT) and a 3-minute maximal test at 4.5% body-mass resistance (relative peak power RPP, average power AvgP, power drop %drop). Tests were separated by ≥48 h and repeated after 1 week and (for the subgroup) after 3 weeks.
Results
After 1 week, no significant time × group interactions for any measure: VO2max (p=0.364), VT (p=0.514), TTE (p=0.540), RPP (p=0.134), AvgP (p=0.398), %drop (p=0.823). After 3 weeks, active-group VO2max significantly increased by 4.8 ml·kg⁻¹·min⁻¹ (p=0.042) vs. only 0.9 in placebo. A 95%-CI analysis showed significant TTE gains in the active group at both 1 week (+28.1 s) and 3 weeks (+69.8 s); placebo showed no such gains. Additionally after 3 weeks, VO2max (+4.8 ml·kg⁻¹·min⁻¹) and VT (+0.7 L·min⁻¹) improved.
Conclusions
The authors conclude that a Cordyceps militaris-containing blend can improve tolerance to high-intensity exercise, with a more pronounced effect from chronic intake (3 weeks) than a single 1-week course.
Worth noting
This study is often cited as "proof" of an ergogenic C. militaris effect, but the design has real limitations. First, total sample is 28, and the 3-week chronic analysis was run on a subgroup of only 10 volunteers without a stated selection method — longitudinal statistical power is low. Second, it used not a pure C. militaris single supplement but a commercial "mushroom blend" of undisclosed composition, so cordycepin's contribution cannot be separated from other components. Third, the placebo is maltodextrin — neither isoenergetic nor iso-tasting versus the mushroom blend, which could theoretically break blinding. Finally, the sample is young untrained or moderately trained men and women, so extrapolation to elite athletes or the elderly is unjustified. The result reads better as a hypothesis-generating pilot than as confirmation of clinical efficacy.