Supplement
Cordyceps
Mushroom · Cordyceps militaris / sinensis
Cordyceps is the name for a group of sac fungi that have been regarded as a tonic in traditional Chinese medicine for centuries. Today it is advertised above all for endurance. For that there actually are human studies, small, but with a recognizable pattern.
In short
According to the current evidence, cordyceps can slightly improve endurance parameters: a 2025 meta-analysis found significant effects on endurance, ventilatory threshold and maximal oxygen uptake in athletes. The effects are small, rest on only 2 to 3 studies per outcome, and in well-trained cyclists nothing showed. Two randomized studies with 79 healthy people each report higher activity of natural killer cells; whether that protects against infections is open. The biggest catch is the product itself: very different fungi and preparations are sold under the name cordyceps.
What it is
The classic Chinese caterpillar fungus, Cordyceps sinensis (today Ophiocordyceps sinensis), grows as a parasite on moth caterpillars. The wild fungus is rare and considered endangered; according to the German consumer advice center (Verbraucherzentrale), a kilogram can cost up to 80,000 euros. Almost all preparations and most studies therefore work with cultivated forms.
But these are different things. Many older studies used a standardized preparation called Cs-4. Cordyceps militaris is a separate species that is cultivated commercially. In addition there are mycelia of related fungi such as Paecilomyces hepiali. Mycologists describe the classification as long confused; in some cases material was used that can no longer be clearly assigned. When you read studies, it is therefore always worth looking at which fungus exactly was tested.
How it is supposed to work
Cordyceps contains polysaccharides, nucleosides such as cordycepin and adenosine, and sterols. Advertised are higher ATP production in the cells and better oxygen utilization. The ATP claim rests on measurements in the livers of mice, not on data in humans.
What has been measured in humans, by contrast, are performance values from exercise tests, such as the ventilatory threshold, above which breathing rises disproportionately, and maximal oxygen uptake. In addition there are immune markers in the blood. How the fungus influences these values is not clear; the chain of action has not been studied in humans.
Cordyceps became known in the West in 1993, when the runners of the Chinese coach Ma Junren set 4 world records and won 3 world championship titles within a few weeks. Ma attributed this to elixirs made from turtle blood and caterpillar fungus. That is a report, not evidence: in 2016 a letter from Wang Junxia and 9 other athletes became public in which they describe forced doping.
What is well supported
Endurance is the best studied. A 2025 systematic review evaluated 14 randomized studies with 528 athletes on various edible mushrooms. For Cordyceps sinensis there were 4 studies lasting 2 to 12 weeks, and the pooled data showed improvements in endurance (P = 0.05), ventilatory threshold (P = 0.03) and maximal oxygen uptake (P = 0.04), each with low variation between the studies. Individual studies fit this: amateur marathon runners ran a faster 5 km time after 12 weeks, and trained long-distance runners lasted longer until exhaustion in a crossover trial.
In healthy 50- to 75-year-olds, a double-blind study over 12 weeks found the metabolic threshold rose by 10.5 percent and the ventilatory threshold by 8.5 percent. There are also human data for the immune system: in two placebo-controlled studies with 79 healthy adults each, the activity of natural killer cells rose more than under placebo, in one of them by 38.8 percent. In chronic kidney disease, a Cochrane review of 22 studies with 1,746 participants found better creatinine values as an add-on to standard therapy.
What the studies show
Meta-analysis Shu 2025
14 randomized studies with 528 athletes on mushroom preparations, 8 of them with 288 athletes in the pooled analysis, spread across several species of fungus. For Cordyceps sinensis, 2 to 3 studies were pooled per outcome. Result: significant, small improvements in endurance, threshold and maximal oxygen uptake. Only 3 of the studies mentioned side effects, and not systematically.
Parcell 2004, trained cyclists
22 endurance-trained cyclists took Cs-4 or placebo for 5 weeks. Maximal oxygen uptake, threshold and time trial remained unchanged; the time trial took 61.4 minutes under placebo and 62.1 minutes under cordyceps. In well-trained people the margin is apparently small.
Chen 2010, healthy older adults
20 people between 50 and 75 years, 12 weeks, double-blind. Metabolic threshold plus 10.5 percent, ventilatory threshold plus 8.5 percent; maximal oxygen uptake did not change. The authors themselves call it a pilot study.
Hirsch 2017, mushroom blend
28 young adults received a mushroom blend with Cordyceps militaris or placebo. After one week no significant difference; in the 10 participants who continued for 3 weeks, maximal oxygen uptake rose by 4.8 ml/kg/min versus 0.9 under placebo. Because it was a blend, the effect cannot be attributed to cordyceps alone.
Kang 2015 and Jung 2019, immune markers
Two placebo-controlled studies with 79 healthy adults each, 4 and 8 weeks respectively. Tested were Cordyceps militaris and a mycelium extract from Paecilomyces hepiali. In both, the activity of natural killer cells rose more than under placebo, in the second by 38.8 percent. Frequency of infections was not recorded; no relevant side effects occurred.
Where the data stop
The studies are small and short, and the preparations differ greatly. A 2026 narrative review found 5 studies with 321 participants for Cordyceps militaris and called the results inconsistent, with small samples, mostly missing registration and non-standardized preparations. In well-trained cyclists the effect did not appear. The immune studies measure blood values, not whether someone gets sick less often. The kidney studies are mostly methodologically weak, concern patients on standard therapy and say nothing about healthy people.
For higher ATP production in humans, for libido and potency, and for anti-aging we found no human studies. The joint expert commission of BVL and BfArM wrote in 2015 that such promises lacked a scientific basis. Whether cultivated Cordyceps militaris works like Cordyceps sinensis has not been studied; comparative human studies are lacking.
Status, approval and legal
A joint expert commission of BVL and BfArM concluded in 2015 that products made from Cordyceps sinensis, Coriolus versicolor and Ganoderma lucidum are to be regarded not as foods but as medicines, whose efficacy and safety would have to be demonstrated in a marketing authorization. They are not approved as medicines in Germany. According to the German consumer advice center, the fruiting bodies have been used in the EU as dietary supplements for more than 20 years. Because it is not an approved active ingredient, this page gives no dosage. Relevance to doping is not noted for the fungus in the sources checked; athletes should nonetheless make sure to use tested products.
Safety
No serious side effects were observed in the studies, and in the immune study with 79 men no significant ones either. But that is less reassuring than it sounds: in the sports meta-analysis, only 3 studies reported on side effects at all, and long-term data are lacking. The bigger risk lies in quality. According to BVL and BfArM, the identity of material sold as caterpillar fungus is fundamentally open to doubt, and arsenic compounds have been detected in Cordyceps sinensis. Because cordyceps raises immune markers in studies, you should clarify with a physician beforehand whether it makes sense if you have an autoimmune disease or take immunosuppressants; there are no interaction studies on this. No data are available for pregnant and breastfeeding women. We found no upper limit from EFSA, BfR or NIH.
BK-Score Thin human evidence
| Human evidence | 5 | |
|---|---|---|
| Mechanism | 4 | |
| Safety data | 4 | |
| Hype gap | 3 | |
| Track record of use | 7 |
The endurance data are small but consistent enough for a cautious plus: a systematic review (Shu et al., Front Nutr 2025) evaluated 14 RCTs with 528 athletes on edible mushrooms; for Cordyceps sinensis (4 RCTs, 2 to 12 weeks), pooled data from 2 to 3 studies each showed improvements in endurance (P = 0.05), ventilatory threshold (P = 0.03) and VO2peak (P = 0.04). The frequently cited 8 studies with 288 athletes concern all species of fungus together. In 22 trained cyclists (5 weeks) no effect (Parcell 2004); in 20 healthy older adults metabolic threshold +10.5 percent without change in VO2max (Chen 2010). For the immune system there are human data at the surrogate level: two RCTs with 79 healthy people each with higher NK cell activity (Kang 2015; Jung 2019). In chronic kidney disease, Cochrane finds better creatinine values across 22 studies with 1,746 participants, with high or unclear risk of bias in all studies. For ATP in humans, libido and anti-aging there are no human data. The preparations are taxonomically inconsistent; side effects were reported at all in only 3 sports studies.
The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)
Frequently asked questions about cordyceps
Does cordyceps increase endurance?
Probably a little. A 2025 meta-analysis found small, significant improvements in endurance and oxygen uptake in athletes, though each from only 2 to 3 studies. In well-trained cyclists, one study showed no effect.
What is the difference between Cordyceps sinensis and militaris?
They are two different species of fungus. The wild caterpillar fungus sinensis is rare and expensive; militaris is cultivated commercially. Whether both work the same way has not been compared in humans.
Does cordyceps strengthen the immune system?
Two randomized studies with 79 healthy people each show higher activity of natural killer cells. Whether this means getting sick less often was not studied.
Does cordyceps help with libido or potency?
There are no human studies on this. In 2015 the expert commission of BVL and BfArM assessed such advertising claims as lacking a scientific basis.
When does one notice an effect?
The studies mostly ran 2 to 12 weeks; in one study nothing showed after one week, but something did after 3 weeks. A single study found a faster reaction time after exercise following a single dose, but no higher performance.
Is cordyceps doping?
The fungus is not listed as a doping agent in the sources checked. The legendary records of 1993 that made it famous are suspected of having been due to actual doping. Because of possible contamination, competitive athletes should only use tested products.
Related
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- Same categoryLion’s Mane
- Also for energy and immunityPanax Ginseng
- Same goal: Muscle buildingTribulus Terrestris
- Same goal: More energyMaca
- Same goal: Strengthen the immune systemColostrum (bovine)
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Sources
- Shu et al., Front Nutr 2025
- Parcell et al., Int J Sport Nutr Exerc Metab 2004
- Chen et al., J Altern Complement Med 2010
- Hirsch et al., J Diet Suppl 2017
- Kang et al., J Med Food 2015
- Jung et al., BMC Complement Altern Med 2019
- Zhang et al., Cochrane Database Syst Rev 2014 (CD008353)
- Jędrejko et al., Nutrients 2026
- BVL, Medicinal mushrooms – food or medicine?, 2015
- Hersh, report on the letter from the Chinese runners, 2016
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-26.