Ophiocordyceps sinensis (wild caterpillar fungus) and Cordyceps militaris (cultivated) are two different fungi in different genera and families. Most supplements contain neither wild fungus but the laboratory grown CS-4 strain. · supplement
Evidence tier: weak
Boosts athletic performance and stamina by increasing oxygen utilisation and ATP production, a natural performance and energy enhancer with strong evidence
Proposed, not settled. Cordycepin and the polysaccharides are thought to support mitochondrial energy production and improve how efficiently the body uses oxygen during exercise, which fits the trial finding that exercise thresholds moved while VO2 max did not (PMID 20804368, PMID 41280379). Immune activity (T helper cell stimulation, prolonged lymphocyte survival, raised TNF alpha and IL-1, increased natural killer cell activity) is preclinical, from cells and animals (MSK About Herbs).
Weak. A real but fragile signal for exercise endurance, and not much else that stands up. NCCIH has no cordyceps fact sheet, so the usual top tier referee has not graded it. The classic trial gave CS-4, 333 mg three times a day, to 20 healthy older adults for 12 weeks: two measures of exercise threshold improved, by 10.5 and 8.5 percent, but VO2 max did not change at all, and the authors call their own work a pilot study (PMID 20804368). A 2025 systematic review and meta analysis in athletes reported improved endurance, ventilatory threshold and VO2peak, but the cordyceps result rests on only 3 studies, the p values are borderline (0.05, 0.03, 0.04), the authors flag likely publication bias because 13 of 14 trials reported favourable outcomes, and most studies carried some concerns for risk of bias (PMID 41280379). A frequently cited altitude study is a Rhodiola plus Cordyceps combination, so its result cannot be credited to cordyceps alone (PMID 25251930). MSK About Herbs sums it up in one line: studies on exercise performance in healthy subjects yielded mixed results. Fatigue and low energy are largely traditional and mechanistic with no strong standalone trial found. Muscle recovery, which the seed grades strong, has nothing found to support it. Brain fog, chronic fatigue syndrome and fibromyalgia have no verifiable human source. Immune effects are laboratory and animal work, not demonstrated human outcomes. The US Department of Defense supplement safety programme (OPSS) states there is a lack of scientific evidence to support functional mushrooms for any purpose other than as food.
Clinical trials used 333 mg three times a day of CS-4 for 12 weeks, and 1.8 g to 3 g a day of Cordyceps militaris mycelium for 16 weeks. LiverTox reports commercial products recommend 0.5 to 4 g daily, a notably higher range than the trials (333 mg to 1.8 g daily).
Take 1 to 3g of standardised extract daily. Effects on athletic performance and VO2 max are best measured over 6 to 8 weeks. Works well taken 1 to 2 hours before exercise.
Well tolerated in short term clinical trials. Limited safety data in pregnancy and lactation. May potentiate immunosuppressant drugs. Use with caution in autoimmune conditions.
Pregnancy: avoid
Breastfeeding: avoid
Active compounds: cordycepin (3'-deoxyadenosine), polysaccharides
Remedies using Cordyceps · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.