Evidence explainerCordyceps

Cordyceps Benefits: The Endurance Claim Failed Its Best Test

Cordyceps is sold for stamina. The cleanest trial in trained cyclists found nothing; the positive results come from blends, tiny subgroups and lab immune markers.

By Kymata Health editorial teamPublished October 9, 2026Last reviewed October 9, 2026

Medical review pending. Written by our editorial team from the studies cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • In 22 trained cyclists, 3 g/day of Cordyceps sinensis for 5 weeks did not change VO2peak or time-trial performance versus placebo [1].
  • A mushroom blend containing Cordyceps militaris had no effect after 1 week; after 3 weeks, VO2max rose in the 10 people who continued [2].
  • In 79 healthy men, 1.5 g/day of C. militaris for 4 weeks raised natural killer cell activity versus placebo [3].
  • A 30-day cordyceps and reishi product found no cognitive benefit in 96 young adults [4].

Safety at a glance

From our Cordyceps monograph. Published interactions and cautions only, each with its source.

Who should be careful

  • Product variability. Trials used different species and products, including blends, so results from one product may not apply to another.[1][2][3]
  • Before you start. Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[3]

Full Cordyceps safety section

The evidence, graded

Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.

  • Grade CNo effectAerobic capacity and endurance time trialCordyceps · RCT · n=22 · 2004 · PMID 15118196VO2peak, ventilatory threshold and time-trial performance did not change and did not differ from placebo (time trial 62.1 vs 61.4 min).
  • Grade DMixedHigh-intensity exercise toleranceCordyceps · RCT · n=28 · 2017 · PMID 27408987After 1 week, no significant effects on VO2max, ventilatory threshold, time to exhaustion or power. After 3 weeks, VO2max rose 4.8 ml/kg/min in the 10 who continued, and confidence-interval analysis showed longer time to exhaustion.
  • Grade CImprovedNatural killer cell activity and lymphocyte proliferationCordyceps · RCT · n=79 · 2015 · PMID 26284906NK cell activity, lymphocyte proliferation, IL-2 and interferon-gamma rose more than with placebo; other Th1 cytokines did not. No statistically significant adverse reactions.
  • Grade CNo effectCognitive functionCordyceps · RCT · n=96 · 2017 · PMID 29199566No significant differences between groups in global cognition, memory, executive function, attention, processing speed, visuospatial, verbal or motor skills.

Endurance: a clear null

In a 5-week placebo-controlled trial, 22 endurance-trained male cyclists took 3 g/day of a Cordyceps sinensis product [1]. VO2peak and ventilatory threshold did not change, and time-trial results did not differ (61.4 min on placebo vs 62.1 min on cordyceps) [1].

High-intensity exercise: a blend and a subgroup

In a trial of 28 young adults, 4 g/day of a mushroom blend containing Cordyceps militaris produced no significant changes in VO2max, time to exhaustion or power after 1 week [2]. After 3 weeks, VO2max rose by 4.8 ml/kg/min in the 10 volunteers who continued, versus 0.9 on placebo [2].

Because it was a blend, the effect cannot be pinned on cordyceps, and the 3-week result rests on 10 people [2].

Immune markers

In a 4-week trial of 79 healthy Korean men (39 on cordyceps, 40 on placebo), 1.5 g/day of C. militaris raised NK cell activity, lymphocyte proliferation, IL-2 and interferon-gamma more than placebo, with no significant adverse reactions [3]. These are laboratory markers, not infection outcomes [3].

Focus and memory

In 96 physical-education students, a commercial supplement of Ophiocordyceps sinensis and reishi taken for 30 days showed no differences from placebo in memory, attention, processing speed or other cognitive domains [4]. For safety and the differences between species, read is cordyceps safe.

Quick answers

Is cordyceps good for energy?

The best endurance trial found no change in aerobic capacity or time-trial performance over 5 weeks [1].

How much cordyceps was used in trials?

The trials used 1.5 g/day of C. militaris, 3 g/day of a C. sinensis product, or 4 g/day of a blend [3][1][2].

Does cordyceps boost the immune system?

It raised NK cell activity and some cytokines in one 4-week trial [3]. Whether that changes how often people get sick was not measured [3].

Keep reading

Full monographs

Related articles

Browse the full Supplement & Nutrient Encyclopedia or all supplement articles.

References

  1. [1]Cordyceps Sinensis (CordyMax Cs-4) supplementation does not improve endurance exercise performance. Int J Sport Nutr Exerc Metab, 2004. PMID 15118196
  2. [2]Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation. J Diet Suppl, 2017. PMID 27408987
  3. [3]Cordyceps militaris Enhances Cell-Mediated Immunity in Healthy Korean Men. J Med Food, 2015. PMID 26284906
  4. [4]Clinical Effects of a Commercial Supplement of Ophiocordyceps sinensis and Ganoderma lucidum on Cognitive Function of Healthy Young Volunteers. Int J Med Mushrooms, 2017. PMID 29199566

Cordyceps and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.