The proposed oxygen and ATP pathway
Cordyceps is a fungal genus used in traditional medicine and now sold as an athletic supplement, with cordycepin and related adenosine analogs proposed as its active compounds. The suggested mechanism centers on improved oxygen utilization and support for cellular ATP production, particularly under low-oxygen, hypoxic conditions, which is why it is often marketed for endurance and high-altitude performance.
VO2 max, the maximum rate at which the body can use oxygen during exercise, is the headline metric these claims attach to, since it reflects how efficiently oxygen is delivered and consumed.
What the human studies actually show
Human trials have produced mixed results. Some small studies, often using cultured Cordyceps products, report modest improvements in measures of aerobic capacity or tolerance to high-intensity exercise, while others find no meaningful change, and effects appear more often in older or untrained participants than in trained athletes. The evidence is therefore preliminary and the practical benefit, if any, is likely small.
This is general educational information, not medical advice. Supplement quality and species vary widely, and Cordyceps can interact with some medications, so consult a qualified professional before use.