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Cordyceps: Does This Mushroom Actually Improve Exercise Performance?

Botanical / supplement

A look at what the research actually shows about cordyceps and endurance.

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By the Ration Editorial Team · Reviewed against primary research · Updated July 13, 2026

Key takeaways

  • Cordyceps is a fungus used in traditional Chinese medicine, now sold as an exercise and energy supplement
  • Our database grade for cordyceps and VO2max is A, based on two randomized controlled trials
  • Evidence is strongest in older adults, weaker and mixed in trained athletes
  • Generally considered safe short term, but supplement quality varies widely

What is cordyceps?

Cordyceps is a genus of parasitic fungi that has a long history in traditional Chinese medicine.

The wild form, Cordyceps sinensis, grows on caterpillar larvae in high altitude regions of China and Tibet. It is rare and expensive.

Most modern supplements use a lab grown strain called Cs-4, which is fermented in a lab rather than harvested from insects. This makes it more affordable and scalable.

People take cordyceps mainly for energy, stamina, and exercise performance, though it is also studied for effects on the immune system and blood sugar.

How is it supposed to work?

Cordyceps is thought to increase the body's production of ATP, the molecule cells use for energy.

Some researchers believe it may improve how efficiently the body uses oxygen during exercise, which is why VO2max, a measure of maximum oxygen uptake, is the main outcome studied.

Compounds like cordycepin and adenosine are often cited as the active ingredients responsible for these effects, though human data on their specific mechanisms is limited.

Does cordyceps improve exercise performance?

Our database gives cordyceps a grade A consensus for increasing VO2max, based on two randomized controlled trials.

The clearest positive result comes from a double-blind, placebo-controlled trial in healthy older adults, who took Cs-4 for weeks and saw improvements in VO2max and ventilatory threshold compared to placebo[1].

A separate randomized trial looked at a commercial herbal formula containing cordyceps in trained cyclists. This study did not find meaningful improvements in performance measures like time trial results or metabolic markers[2].

Taken together, the trials suggest cordyceps may help exercise capacity in older or less conditioned adults, where there is more room for improvement.

In already well trained athletes, the effect appears smaller or absent. This is a common pattern in supplement research: benefits often show up more clearly in people who start from a lower baseline of fitness.

It is also worth noting the study in cyclists used a multi-herb formula, not cordyceps alone, which makes it harder to isolate cordyceps' specific contribution.

What forms does it come in?

Cordyceps is not a significant food source in the typical Western diet. Almost all human exposure comes through supplements.

Because Cordyceps sinensis and the cultivated Cordyceps militaris species differ, and potency varies by extraction method, dosing is not standardized across brands.

How much do you need?

The trial in older adults used Cs-4 extract over a period of several weeks before testing exercise performance[1].

There is no established effective dose for the general population, and label doses on commercial products vary considerably.

Because research is limited to a small number of trials, it is hard to say whether higher doses would produce better results or simply more side effects.

Is it safe?

In the trials available, cordyceps was generally well tolerated over the study periods, with no serious adverse effects reported[1][2].

Long term safety data in humans is limited, since most trials run for only weeks.

Who might consider it?

Bottom line

Cordyceps has a genuinely interesting research signal for VO2max, especially in older adults, backed by our database's grade A consensus.

But the evidence base is still small, just two randomized trials with different populations and different results. This is not the kind of overwhelming evidence that applies to everyone equally.

If you already train intensely, cordyceps is unlikely to be a game changer. If you are older or newer to exercise, the existing trial data is more encouraging, though still preliminary.

Frequently asked questions

Does cordyceps really increase VO2max?

In a trial of healthy older adults, Cs-4 cordyceps improved VO2max and ventilatory threshold compared to placebo[1], though a separate study in trained cyclists using a multi-herb formula did not show clear benefits[2].

Is cordyceps good for athletes?

The evidence is mixed. Benefits appeared in older, less trained adults[1], but not in a trial of competitive cyclists[2].

How long does it take for cordyceps to work?

The positive trial in older adults measured effects after several weeks of daily use[1], though there is no firmly established timeline for benefits.

Is cordyceps safe to take daily?

Short term trials found it generally well tolerated[1][2], but long term human safety data is limited.

Sources

  1. Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: a double-blind, placebo-controlled trial · PMID 20804368
  2. Effects of a commercial herbal-based formula on exercise performance in cyclists · PMID 15076794