Cordyceps for Runners: What 10 Studies Show

Cordyceps & Athletic Performance

+4.8 ml/kg/min

Three weeks of Cordyceps militaris supplementation increased VO2 max by 4.8 ml/kg/min and extended time to exhaustion by 69.8 seconds in a placebo-controlled trial.

Hirsch et al., Journal of Dietary Supplements, 2017

10.5%

increase in metabolic threshold with Cs-4 over 12 weeks (Chen et al., 2010)

+51%

CD34+ stem cell count at 3h post-exercise with cordyceps (Dewi et al., 2024)

528

athletes across 14 RCTs included in the 2025 meta-analysis (Shu et al., 2025)

Hirsch et al., Journal of Dietary Supplements, 2017

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Cordyceps has a long reputation in endurance sports. That reputation grew partly from the 1993 Chinese National Games, where record-breaking runners attributed their performance to a cordyceps-based regimen, and partly from centuries of use at high altitude in the Himalayas. For the full backstory, see cordyceps and the 1993 Chinese Olympic controversy. The question for runners today is simpler: what does controlled research actually show? Ten studies, ranging from randomized trials in marathoners to cell-level mechanistic work, provide a picture that is encouraging but uneven. The effects appear real for some populations and nonexistent for others, and the reason for that gap is itself informative.

How Cordyceps Affects the Body During Exercise

Two species dominate the research: Cordyceps sinensis (often as the fermented Cs-4 extract) and Cordyceps militaris (whole fruiting body or extract). They share some bioactive compounds, particularly cordycepin and adenosine, but differ in concentration and composition. The proposed mechanisms relevant to runners involve three pathways.

First, ATP production. Choi et al. (2020) tested C. militaris ethyl acetate extract in mice and found that it increased grip strength at levels comparable to red ginseng. Biochemical analysis showed effects on biomarkers related to the ATP generation pathway, with little influence on muscle fatigue markers directly. The authors concluded that cordyceps may improve exercise capacity through energy production rather than fatigue suppression.^[1]

Second, AMPK activation. Song et al. (2015) gave C. militaris fruit body extract to mice for two weeks and measured performance across forced swimming, forced running, and rotating rod tests. Supplementation significantly delayed fatigue onset across all three tests. At the molecular level, CM administration increased ATP levels and antioxidant enzyme activity while reducing lactic acid, lactate dehydrogenase, malondialdehyde, and reactive oxygen species. The fatigue recovery effect operated primarily through activation of AMPK and AKT/mTOR pathways.^[2]

Third, hypoxia tolerance. Singh et al. (2013) demonstrated that C. sinensis aqueous extract protected human lung epithelial cells under hypoxic conditions by inducing heme oxygenase-1 (HO-1) and metallothionein through Nrf2 activation. This reduced oxidative stress and upregulated HIF-1, erythropoietin, and VEGF. Under normal oxygen conditions, cordyceps had no effect on these pathways, suggesting the benefit is specific to oxygen-depleted states.^[3] For runners, this is relevant during threshold training, altitude exposure, and race-pace efforts where oxygen demand exceeds supply. For a detailed analysis of this mechanism, see cordyceps and VO2 max: can a mushroom improve oxygen uptake.

These are preclinical and in vitro findings. They establish biological plausibility but do not confirm that the same effects occur in human runners at supplement doses. The human trials below test whether they do.

VO2 Max and Ventilatory Threshold: The Human Data

The largest synthesis of the evidence comes from Shu et al. (2025), a systematic review and meta-analysis that identified 14 randomized controlled trials involving 528 athletes. Eight studies (288 participants) met criteria for quantitative synthesis. For Cordyceps sinensis specifically, meta-analysis showed statistically significant improvements in endurance performance (p=0.05), ventilatory threshold (p=0.03), and VO2 peak (p=0.04), all with low heterogeneity across studies.^[4]

The individual trials behind that meta-analysis tell a more nuanced story.

Hirsch et al. (2017) enrolled 28 individuals (mean age 22.7 years) in a randomized, double-blind, placebo-controlled study using 4 g/day of a C. militaris-containing mushroom blend. After one week, no significant differences emerged for VO2 max, ventilatory threshold, time to exhaustion, or power output. After three weeks, VO2 max improved significantly in the supplement group (+4.8 ml/kg/min) versus placebo (+0.9 ml/kg/min, p=0.042). Analysis of 95% confidence intervals also showed significant improvements in time to exhaustion after both one week (+28.1 seconds) and three weeks (+69.8 seconds).^[5]

Chen et al. (2010) tested a lower dose of Cs-4 (333 mg three times daily, roughly 1 g/day) for 12 weeks in 20 healthy adults aged 50-75. The metabolic threshold, above which lactate accumulates, increased by 10.5% (from 0.83 to 0.93 L/min, p<0.02). The ventilatory threshold increased by 8.5% (from 1.25 to 1.36 L/min). Neither threshold changed in the placebo group. VO2 max did not change in either group.^[6]

The distinction matters for runners. VO2 max sets the ceiling for aerobic capacity, but the ventilatory and metabolic thresholds determine the pace a runner can sustain before lactate accumulates and performance degrades. A runner whose threshold shifts upward can maintain a faster pace at the same perceived effort, even if their VO2 max remains unchanged.

The Null Result: Why Trained Cyclists Saw No Benefit

Parcell et al. (2004) conducted the study most frequently cited by skeptics. Twenty-two male endurance-trained cyclists supplemented with 3 g/day of CordyMax Cs-4 for five weeks. Baseline VO2 peak was approximately 59 ml/kg/min in both groups. After supplementation, VO2 peak, ventilatory threshold, and time trial performance showed no significant differences between supplement and placebo groups. The trained cyclists completed time trials in nearly identical fashion (61.4 versus 62.1 minutes).^[7]

This result is not contradicted by the positive studies. It reveals a pattern. The Hirsch trial recruited recreationally active young adults, not competitive athletes. The Chen trial enrolled older adults with no specific training background. The Parcell cyclists had baseline fitness levels (VO2 peak ~59 ml/kg/min) that already approached or exceeded the improvements seen in other trials. A supplement that raises VO2 max by 4.8 ml/kg/min in someone starting at 40 may have no measurable effect in someone already at 59. This ceiling effect is common across ergogenic aids and is not unique to cordyceps. For a full breakdown of all clinical trials, see cordyceps and exercise performance: what the clinical trials show.

Altitude Training and Endurance: A Combined Approach

Chen et al. (2014) tested whether combining Rhodiola crenulata and Cordyceps sinensis during two weeks of altitude training (2,200 meters) would produce greater aerobic gains than altitude training alone. Eighteen male subjects received either 1,400 mg Rhodiola plus 600 mg cordyceps daily or placebo. After two weeks, the supplement group improved exhaustive run time by 5.7% versus 2.2% in placebo (p<0.05). The supplement also prevented the decline in parasympathetic nervous system activity typically seen during altitude training (placebo: -51% versus supplement: -41%, p<0.05). Both groups showed comparable increases in red blood cells, hematocrit, and hemoglobin.^[8]

Because this study combined cordyceps with Rhodiola, the specific contribution of cordyceps cannot be isolated. The preserved autonomic nervous system balance is relevant for runners who use altitude camps, since sympathetic overdrive during altitude training blocks recovery and limits adaptation. For runners interested in the altitude connection, see cordyceps and high-altitude performance: the Tibetan tradition meets modern science.

Recovery: Muscle Damage and Stem Cell Recruitment

Dewi et al. (2024) produced the first human evidence for cordyceps accelerating post-exercise muscle repair. In a randomized, double-blind, placebo-controlled crossover study, 14 young adults (mean age 24) received either 1 g of C. sinensis or placebo before high-intensity interval exercise on a cycle ergometer at 120% of maximal aerobic power. Multiple muscle biopsies were taken from the vastus lateralis.

The exercise protocol doubled VEGF mRNA at 3 hours post-exercise (p=0.006). A significant necrotic cell infiltration (+284%, p=0.05) appeared at 3 hours and resolved within 24 hours. Cordyceps supplementation substantially reduced this necrotic response. CD34+ stem cells increased at 24 hours post-exercise in both groups, but cordyceps accelerated this response to 3 hours (+51%, p=0.002). This earlier stem cell arrival contributed to a four-fold expansion of Pax7+ satellite cells (p=0.01), the muscle-specific stem cells responsible for repair and regeneration.^[9]

For runners accumulating training volume, the rate of muscle repair between sessions determines how quickly they can absorb another hard workout. Faster satellite cell activation does not mean a runner can ignore recovery, but it may widen the window for productive training.

Iron Status and Sports Anemia in Distance Runners

Nakamura et al. (2024) addressed a problem specific to distance runners: sports anemia. Long-distance training increases iron loss through foot-strike hemolysis, sweat, and GI microbleeding. Declining ferritin and hemoglobin levels during heavy training blocks directly impair oxygen transport capacity and race performance.

In a placebo-controlled, double-blind trial, 22 long-distance runners received either C. militaris mycelium extract or placebo for 16 weeks during pre-season training. Serum ferritin change rates were moderately increased in the cordyceps group but decreased in placebo. The differences reached significance at 4 weeks and 8 weeks (p<0.05). Hemoglobin and hematocrit change rates were significantly higher in the cordyceps group at 8 weeks (p<0.05). Additionally, creatine kinase, a marker of muscle damage, was significantly lower in the cordyceps group at 16 weeks (p<0.05), despite both groups starting above the normal range.^[10]

This is the first trial to measure cordyceps effects on iron-status biomarkers in competitive runners. The mechanism likely involves maintaining iron stores rather than increasing absorption, since the cordyceps group showed suppressed ferritin decline rather than ferritin elevation. For runners in high-mileage training blocks, maintaining iron stores is often the limiting factor for sustained performance across a season.

Why Results Vary by Fitness Level

The pattern across these ten studies suggests a relationship between baseline fitness and supplement response. Recreationally active adults (Hirsch) and older adults (Chen 2010) showed measurable improvements. Trained endurance cyclists with elite-level VO2 values (Parcell) showed none.

Several explanations are consistent with this pattern. Athletes with high baseline aerobic capacity may already have optimized the pathways that cordyceps appears to influence: mitochondrial density, ATP production efficiency, and lactate clearance. Alternatively, the absolute magnitude of cordyceps effects may be too small to detect against the normal variability of performance in well-trained athletes. A 4.8 ml/kg/min shift is easily measured in someone with a VO2 max of 40, but falls within day-to-day test variability for someone at 60.

Dose also plays a role. The Hirsch trial used 4 g/day and showed effects at three weeks. The Chen trial used 1 g/day and required 12 weeks for threshold changes. The Parcell trial used 3 g/day for five weeks in a population that may not respond regardless of dose. Duration and dose interact in ways that the current evidence base cannot fully resolve. For a focused discussion of timing questions, see how long does cordyceps take to improve athletic performance.

What the Evidence Does and Does Not Support

The 2025 meta-analysis by Shu et al. provides the strongest available summary: cordyceps supplementation produces statistically significant but modest improvements in endurance performance, ventilatory threshold, and VO2 peak across pooled data from randomized controlled trials. The effects are most apparent in recreationally active individuals and are not reliably observed in highly trained athletes.

Beyond performance, the 2024 studies introduce two new dimensions. Dewi et al. showed accelerated muscle repair at the cellular level, the first human evidence for cordyceps affecting post-exercise recovery through stem cell mechanisms. Nakamura et al. showed preserved iron stores in distance runners during heavy training, addressing a practical problem that limits many runners' ability to maintain fitness across a season.

The evidence has clear limits. Most trials are small (14 to 28 participants). The marathon-specific data is sparse. Species and extract type vary across studies, making direct comparisons difficult. The null result in trained cyclists is robust and consistent with the broader ergogenic supplement literature, where diminishing returns at higher fitness levels are the norm rather than the exception.

The Bottom Line

Cordyceps supplementation shows statistically significant improvements in VO2 peak, ventilatory threshold, and endurance performance across meta-analytic data from 528 athletes. The effects are clearest in recreationally active and older populations, with no measurable benefit in highly trained endurance athletes. Newer research from 2024 adds evidence for accelerated post-exercise muscle repair through stem cell recruitment and maintained iron stores in distance runners during heavy training, expanding the potential relevance beyond performance alone.

Frequently Asked Questions

Does cordyceps actually improve running performance?

A 2025 meta-analysis of 14 randomized controlled trials (528 athletes) found that Cordyceps sinensis supplementation significantly improved endurance performance (p=0.05), ventilatory threshold (p=0.03), and VO2 peak (p=0.04). Individual trials show the effect is most pronounced in recreationally active and older adults. A 2004 trial in trained cyclists with baseline VO2 of ~59 ml/kg/min found no improvement, suggesting fitness level mediates the response.

How much cordyceps should a runner take?

Trials showing positive results used doses from 1 g/day (Cs-4 extract over 12 weeks in Chen et al., 2010) to 4 g/day (C. militaris blend over 3 weeks in Hirsch et al., 2017). Higher doses produced faster responses: 4 g/day showed VO2 max improvement at 3 weeks, while 1 g/day required 12 weeks for threshold changes. The Shu et al. (2025) meta-analysis noted a dose range of 2-3 g/day across most positive studies.

How long does cordyceps take to work for exercise?

Time to exhaustion showed improvement after just one week of 4 g/day supplementation (+28.1 seconds in Hirsch et al., 2017). VO2 max changes required three weeks at that dose. At lower doses (1 g/day), metabolic and ventilatory threshold improvements emerged at 12 weeks (Chen et al., 2010). Most clinical effects appear between 3 and 12 weeks depending on dose and the metric measured.

Is cordyceps good for marathon training?

Two studies are directly relevant to marathon runners. Nakamura et al. (2024) showed that C. militaris extract maintained serum ferritin and hemoglobin levels in long-distance runners during 16 weeks of pre-season training, while placebo runners showed declining iron stores. Dewi et al. (2024) demonstrated that pre-exercise cordyceps accelerated muscle stem cell recruitment by 51%, which could support recovery between hard training sessions.

Does cordyceps increase VO2 max?

In Hirsch et al. (2017), three weeks of 4 g/day C. militaris increased VO2 max by 4.8 ml/kg/min versus 0.9 in placebo (p=0.042). However, Chen et al. (2010) found no VO2 max change with 1 g/day Cs-4 over 12 weeks despite significant threshold improvements. Parcell et al. (2004) found no VO2 peak change in trained cyclists. The effect on VO2 max appears dose-dependent and limited to individuals below elite fitness levels. See cordyceps and VO2 max for detailed analysis.

Cordyceps sinensis vs militaris for athletes which is better?

Both species have shown ergogenic effects, but in different contexts. C. militaris produced VO2 max and time-to-exhaustion improvements in the Hirsch (2017) trial and ATP pathway activation in Choi (2020). C. sinensis (as Cs-4 extract) improved lactate and ventilatory thresholds in Chen (2010) and boosted altitude training adaptation in Chen (2014). The 2025 meta-analysis pooled both species and found significant endurance benefits. Current evidence does not definitively favor one over the other.

Sources & References

1. 1RTHM-00613·Choi, Eunhyun et al. (2020). “Beneficial Effect of Cordyceps militaris on Exercise Performance via Promoting Cellular Energy Production..” Mycobiology.Study breakdown →PubMed →↩
2. 2RTHM-00401·Song, Jingjing et al. (2015). “Studies on the Antifatigue Activities of Cordyceps militaris Fruit Body Extract in Mouse Model..” Evidence-based complementary and alternative medicine : eCAM.Study breakdown →PubMed →↩
3. 3RTHM-00305·Singh, Mrinalini et al. (2013). “Cordyceps sinensis increases hypoxia tolerance by inducing heme oxygenase-1 and metallothionein via Nrf2 activation in human lung epithelial cells..” BioMed research international.Study breakdown →PubMed →↩
4. 4RTHM-00951·Shu, Meng-Yuan et al. (2025). “Effects of fungal supplementation on endurance, immune function, and hematological profiles in adult athletes: a systematic review and meta-analysis..” Frontiers in nutrition.Study breakdown →PubMed →↩
5. 5RTHM-00473·Hirsch, Katie R et al. (2017). “Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation..” Journal of dietary supplements.Study breakdown →PubMed →↩
6. 6RTHM-00176·Chen, Steve et al. (2010). “Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: a double-blind, placebo-controlled trial..” Journal of alternative and complementary medicine (New York.Study breakdown →PubMed →↩
7. 7RTHM-00075·Parcell, Allen C et al. (2004). “Cordyceps Sinensis (CordyMax Cs-4) supplementation does not improve endurance exercise performance..” International journal of sport nutrition and exercise metabolism.Study breakdown →PubMed →↩
8. 8RTHM-00313·Chen, Chung-Yu et al. (2014). “Rhodiola crenulata- and Cordyceps sinensis-based supplement boosts aerobic exercise performance after short-term high altitude training..” High altitude medicine & biology.Study breakdown →PubMed →↩
9. 9RTHM-01879·Dewi, Luthfia et al. (2024). “Cordyceps sinensis accelerates stem cell recruitment to human skeletal muscle after exercise..” Food & function.Study breakdown →PubMed →↩
10. 10RTHM-01954·Nakamura, Akira et al. (2024). “Effect of the Administration of Cordyceps militaris Mycelium Extract on Blood Markers for Anemia in Long-Distance Runners..” Nutrients.Study breakdown →PubMed →↩