Cordyceps is the only mushroom with human trials that directly tested exercise performance, and the results are mixed, not conclusive. One small study in older adults found a modest improvement in how efficiently the body used oxygen, but no change in VO2max, the standard measure of aerobic fitness. A separate trial in trained young cyclists found no performance benefit at all. No mushroom species, including cordyceps, has evidence strong enough to support a performance claim for healthy young or competitive athletes.
Who Should Be Extra Careful With Cordyceps
Before looking at the research, a few groups need to talk to a doctor before trying any cordyceps product. This includes people who take blood-thinning medication, people with kidney disease, people taking immunosuppressant drugs, and people who are pregnant or breastfeeding. Competitive athletes who are subject to anti-doping testing should also be cautious, because supplement purity and labeling are not tightly regulated, and cross-contamination with banned substances has happened with other sports supplements.
The Three Human Studies Behind the Cordyceps Claim
Almost every athletic performance claim about mushrooms traces back to cordyceps, usually either Cordyceps sinensis or a lab-grown strain called Cs-4. Three human trials make up most of the direct evidence.
- Chen et al., 2010: A 12-week pilot study gave Cs-4 cordyceps to 20 older adults, ages 50 to 75. Ventilatory threshold and metabolic threshold, two measures of how efficiently the body handles oxygen during exercise, both improved by roughly 8 to 10 percent compared with placebo. VO2max itself did not change in either group.
- Parcell et al., 2004: This trial tested 22 trained cyclists over several weeks. VO2peak, ventilatory threshold, and time-trial performance were all statistically the same as placebo. This is the strongest negative result in the cordyceps research, and it used real athletes doing a real endurance task.
- Shu et al., 2025: A meta-analysis pooled 14 randomized trials covering 528 athletes across several mushroom species. It reported a statistically significant improvement in endurance performance, ventilatory threshold, and VO2peak from Cordyceps sinensis specifically, but the authors flagged major differences in extraction method, dose, and product purity between the studies, along with a real concern about publication bias, since 13 of the 14 studies reported favorable results.
Put together, the positive findings come mostly from small studies in older, sedentary adults measuring secondary thresholds, or from a pooled analysis with an acknowledged publication-bias problem. The one clearly negative trial used trained young cyclists and a real-world endurance task. That pattern is a signal, not a coincidence.
Why the Altitude and Traditional-Use Story Isn’t Clinical Evidence
Cordyceps’ athletic reputation started long before any of these trials existed. The fungus has a long history of traditional use at high altitude on the Tibetan Plateau, where low oxygen levels made anything associated with easier breathing valuable. That traditional use is real history, but it is not the same thing as a controlled study measuring VO2max in a lab.
The claim also spread through a well-known story from the 1990s, when a Chinese coach credited cordyceps as part of the diet behind a group of runners who broke world records. That anecdote is often repeated in marketing, but it was never a clinical trial, it involved multiple factors at once, and that era of Chinese distance running later became associated with doping allegations. A single team’s results, filtered through decades of retelling, cannot substitute for a randomized, placebo-controlled study.
What Other Mushroom Species Have Performance Research?
Direct exercise-performance trials are almost entirely limited to cordyceps. Other mushrooms, including reishi and oyster mushroom, have some research on recovery-related markers like inflammation or muscle damage after exercise, but that is a different question from measuring endurance or aerobic capacity during exercise itself. As of now, no other mushroom species has a body of human performance trials comparable to cordyceps, thin as that evidence still is.
Checklist: How to Evaluate a Mushroom Performance Claim
- Does the claim name a specific human study, or just say “studies show”?
- Was the study done in athletes, or in older, sedentary adults? Results don’t transfer automatically between those groups.
- Did the study measure VO2max directly, or only a secondary marker like ventilatory threshold?
- Was it placebo-controlled and randomized, or an open-label or animal study?
- Does the product match the species and strain actually tested, such as Cs-4, or is it a different cordyceps preparation entirely?
- Is the claim followed by a real citation you can look up, or just a vague reference to tradition or anecdote?
What Actually Improves Endurance
For most people, the evidence-backed path to better endurance is still training itself, not a supplement. Federal physical activity guidance for adults recommends at least 150 to 300 minutes of moderate-intensity aerobic activity each week, such as brisk walking, plus muscle-strengthening activity at least two days a week. No dietary supplement, mushroom-based or otherwise, is part of that guidance. If you want to understand how researchers judge whether a supplement claim is trustworthy in the first place, our guide to the evidence hierarchy for mushroom research walks through why human trials outrank cell and animal studies.
Frequently Asked Questions
Does cordyceps increase VO2max?
The evidence is mixed. The main positive pooled analysis found a significant VO2peak improvement tied to Cordyceps sinensis specifically, but it also carries a publication-bias concern. A separate individual trial in trained cyclists found no change in VO2max, ventilatory threshold, or time-trial performance, and the original pilot study in older adults found no VO2max change either, only secondary threshold improvements.
Is it safe for tested athletes to take cordyceps supplements?
This requires individual judgment from a qualified professional. Supplement purity and labeling accuracy vary between manufacturers, and cross-contamination with banned substances has occurred in other supplement categories. Athletes subject to drug testing should discuss any supplement with their team physician or sports governing body before use.
Does it matter whether a product uses Cordyceps sinensis, Cordyceps militaris, or Cs-4?
Yes. Most of the human performance research used Cordyceps sinensis or the lab-grown Cs-4 strain specifically, not Cordyceps militaris, which is more common in many commercial products today. Findings from one strain do not automatically apply to a different one. Our cordyceps research and safety guide covers how these strains differ.
Can any other mushroom boost endurance the way cordyceps claims to?
Not based on current direct performance research. Other species have limited data on recovery markers, but not on endurance or aerobic capacity during exercise. For more on the specific compound researchers think may be behind cordyceps’ effects, see our page on cordycepin, cordyceps’ most-studied bioactive compound.
Evidence Limits
This is a small research area. The positive individual-study findings come from one 12-week pilot study in 20 older adults, a small population that cannot be assumed to represent trained athletes. The negative individual-study finding comes from one trial in 22 cyclists. The 2025 meta-analysis pooling multiple trials found real variation in products and methods across studies, plus a publication-bias concern, which limits how confidently anyone can generalize the results. No large-scale trial in competitive athletes currently exists. If you’re on any medication or have a kidney, liver, or bleeding-related condition, check our mushroom supplement and drug interaction overview before considering any cordyceps product.
This article is for educational purposes only and is not medical advice. It does not diagnose any condition, recommend any dose, or promise any outcome. Talk with a qualified healthcare provider before starting, stopping, or changing any supplement or medication, especially if you are pregnant, breastfeeding, managing a health condition, or subject to anti-doping testing.