Cordyceps
Also sold as: Cordyceps militaris · Ophiocordyceps sinensis · Cs-4
A group of medicinal fungi sold for exercise performance and fatigue. Species, cultivated mycelium and extracts have different evidence and cannot be treated as interchangeable.
Energy
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Research
- Energy: Small trials suggest changes in exercise thresholds in older adults, but no established general energy benefit or increase in maximal oxygen uptake.
REALITY CHECK // The marketing claim of a universal VO2max booster conflicts with the trials: older adults showed threshold changes, while trained cyclists did not improve. Testosterone and broad nootropic claims rely on preclinical models; a small acute reaction-time signal does not establish everyday focus benefits.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
UPPER LIMIT // No established EFSA or NIH upper intake level in this dossier. The studied 1-3 g/day range is not a safety ceiling; long-term safety and marker exposure remain uncertain.
Summary
In a small 12-week trial in adults aged 50-75, Cs-4 increased metabolic threshold by 10.5% and ventilatory threshold by 8.5%, without increasing VO2max. A five-week trial in trained cyclists found no performance benefit. Much of the fatigue, testosterone and cognition narrative remains animal or cell research.
Mechanism
Cordycepin, nucleosides and polysaccharides influence metabolic and immune signalling in experimental models. These mechanisms do not establish a clinical energy or hormone benefit.
Typical studied dose
Cs-4 trials used approximately 1 g/day for 12 weeks in older adults and 3 g/day for five weeks in trained cyclists. A small acute C. militaris crossover trial used 1 g. These amounts refer to their tested preparations, not purified cordycepin.
Upper limit
No established EFSA or NIH upper intake level in this dossier. The studied 1-3 g/day range is not a safety ceiling; long-term safety and marker exposure remain uncertain.
Popular stacks with Cordyceps
Not enough stack data yet. A combination with Cordyceps appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| Fermented C. sinensis mycelium (Cs-4) Best for: Matching the preparation in the exercise trials. |
Extract weight · marker not quantified | 1000–3000 mg | Human exercise trials used this preparation; no marker equivalence across products. Generally tolerated in small trials. |
Studied standard [CHECK // REFERENCE] |
| Cultivated C. militaris fruiting body / powder Best for: A clearly identified species with independent testing. |
Extract weight · marker not quantified | 1000–1000 mg | Cordycepin content varies; a 1 g acute trial does not validate every extract. Concentrated products may cause GI symptoms or sedation; anecdotal reports are not incidence data. |
Caution [CHECK // CAUTION] A powder cannot be converted into a concentrated extract without an assay. One acute protocol is not a chronic target. |
| Wild Ophiocordyceps sinensis Best for: Identifying a high-cost, high-uncertainty product. |
Unstandardized: active content unknown | no comparable trial range | Variable and insufficiently standardized. Contaminant exposure is a key concern. |
Avoid / not comparable [CHECK // AVOID] No transferable trial range; arsenic and adulteration concerns outweigh a presumed premium. |
Common label traps
- TRAP_01 // UNIVERSAL ENDURANCE BOOST
Neither the older-adult nor the trained-cyclist study establishes an increase in VO2max for everyone. - TRAP_02 // NATURAL TESTOSTERONE BOOSTER
Reproductive findings are primarily from cells and rodents; human efficacy is unestablished. - TRAP_03 // ONE MUSHROOM NAME, ONE EFFECT
Wild sinensis, Cs-4 mycelium, Bailing and militaris are not clinically interchangeable.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- CHRONIC KIDNEY DISEASE Limited · benefit
A Cochrane review of 22 trials and 1,746 participants reported improved renal markers, but all trials had high or unclear bias risk. This is adjunctive specialist care, not self-treatment.
PMID 25519252 PMID 38645562 - IMMUNE MARKERS Limited · benefit
One adult beverage RCT examined immune responses; changing immune markers does not prove fewer infections.
PMID 38580687
Reader questions
What can it realistically do?
The most relevant consumer signal is limited exercise-threshold evidence in older, less-trained adults. Fatigue and hormone promises substantially exceed the human data.
Will it cause a caffeine-like crash?
Cordyceps has not been established as a caffeine-like stimulant. Sedation and GI symptoms are reported anecdotally, with no reliable rate or proven crash mechanism.
Can it treat chronic fatigue or low libido?
The dossier does not establish treatment efficacy for ME/CFS or sexual dysfunction. Persistent fatigue or sexual symptoms require assessment rather than escalation of an extract.
Stack interactions
- Caution Anticoagulants / antiplatelets [CAUTION // REVIEW_COMBINATION]
Potential additive bleeding is inferred from preclinical antithrombotic activity, not a quantified human interaction. Review with the prescriber.
PMID 37970560 - Caution Immunosuppressants [CAUTION // REVIEW_COMBINATION]
Immune-stimulatory mechanisms may conflict with treatment; transplant and autoimmune care require specialist decisions.
PMID 33628175 - Caution Rhodiola combinations [CAUTION // REVIEW_COMBINATION]
A multi-ingredient training trial did not establish overall superiority. It cannot isolate a Cordyceps effect or prove synergy.
PMID 33078636
Red flags: interactions and who should avoid it
Interactions
Antiplatelet and glucose-lowering effects are mainly preclinical, making additive bleeding or hypoglycaemia risks plausible but unquantified. Immunomodulation warrants specialist review with immunosuppressants.
Avoid or ask a doctor first if
Avoid unsupervised use during pregnancy, breastfeeding, childhood, transplant care or autoimmune disease. Review use before surgery or with bleeding disorders. Persistent vomiting, allergic symptoms or marked sedation warrant stopping and clinical assessment. Wild material needs independent arsenic and heavy-metal testing.
Sources (PubMed, 7)
- Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: a double-blind, placebo-controlled trial.
PMID 20804368 · 2010 · RCTSmall older-adult RCT: exercise-threshold improvements without a VO2max increase.
- Cordyceps Sinensis (CordyMax Cs-4) supplementation does not improve endurance exercise performance.
PMID 15118196 · 2004 · RCTTrained-cyclist RCT: no endurance performance benefit.
- Acute Cordyceps militaris supplementation and elevated resting oxygen uptake with faster reaction times: A randomized crossover trial.
PMID 42455764 · 2026 · RCTSmall acute crossover: reaction time and resting oxygen uptake, not established maximal performance.
- Cordyceps sinensis (a traditional Chinese medicine) for treating chronic kidney disease.
PMID 25519252 · 2014 · Systematic review / meta-analysisRenal adjunct review with substantial trial-quality limitations.
- A randomized controlled clinical trial examining the effects of Cordyceps militaris beverage on the immune response in healthy adults.
PMID 38580687 · 2024 · RCTHuman beverage RCT on immune response.
- Cordyceps spp.: A Review on Its Immune-Stimulatory and Other Biological Potentials.
PMID 33628175 · 2020 · Narrative reviewReview of immune mechanisms and mostly preclinical biological findings.
- Effects of Concurrent Training and a Multi-Ingredient Performance Supplement Containing Rhodiola rosea and Cordyceps sinensis on Body Composition, Performance, and Health in Active Men.
PMID 33078636 · 2021 · RCTMulti-ingredient training study cannot establish single-ingredient synergy.
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