Clean energy

Clean energy: Cordyceps, oxygen, and why distance runners found it before the gym did

In 1993, at the Chinese national track championships, a group of distance runners broke three world records in five days. One of them, Wang Junxia, dropped under 30 minutes for the 10,000 meters for the first time in history. Coach Ma Junren credited two things: brutal altitude training and a formula based on Cordyceps and turtle blood.

The turtle blood became the scandal. The Cordyceps became the curiosity. In the decades since, this mushroom has worked its way into exercise physiology labs around the world. What's been found is more subtle than the Wang Junxia legend, but solid enough to be worth understanding.

What Cordyceps is

Cordyceps is a genus of parasitic fungi that, in the wild, grow on insect larvae. The two species relevant for human consumption are *Cordyceps sinensis* (the original Tibetan one, harvested above 4,000 meters and sold at absurd prices) and *Cordyceps militaris* (the one cultivated in bioreactors that accounts for almost all commercial supply today).

This last point matters. When you read "Cordyceps" on a label, it's almost always militaris. Good news: similar bioactive profile, sustainable to cultivate, no plundering of Himalayan ecosystems.

The compound credited with most of the effects is cordycepin, an adenosine analogue that acts on cellular energy pathways. Cordyceps also contains polysaccharides, ergosterol, and other bioactives that get less research attention.

How it works at the cellular level

This is where Cordyceps separates from caffeine in a way that changes how you should expect to use it.

Caffeine works on the central nervous system. It blocks adenosine receptors, which are the body's signal for tiredness. That's why you feel awake: not because you have more energy, but because your brain isn't receiving the tired signal. When caffeine clears, the signal returns, sometimes amplified. Hence the crash.

Cordyceps doesn't touch the central nervous system. It works one layer deeper, at the mitochondria. The mitochondria are the energy factories inside every cell. They convert oxygen and nutrients into ATP, the energy currency the body uses for everything, from contracting a muscle to forming a thought. Cordyceps appears to improve the efficiency of this conversion.

In practice, this means: with the same oxygen you breathe, your cells produce slightly more usable energy. It doesn't wake you up. It doesn't speed you up. It increases the amount of work you can do before fatigue sets in. That's a meaningful difference.

What the human evidence shows

The most cited study is Chen and colleagues, published in the *Journal of Alternative and Complementary Medicine* in 2010. They worked with 20 healthy adults aged 50 to 75 over 12 weeks. The group taking 1 gram of Cordyceps extract daily improved their VO2max and ventilatory metabolic threshold. The placebo group did not.

Hirsch and colleagues published in 2017 in the *Journal of Dietary Supplements* a study with young active subjects, this time with *Cordyceps militaris* specifically. Three weeks of supplementation, 4 grams daily. Improvement in VO2max and time to exhaustion in a high-intensity test.

Yi and colleagues ran a smaller 2004 trial with Chinese distance runners, measuring testosterone, cortisol, and performance markers. Recovery markers were better in the Cordyceps group.

What the evidence shows with reasonable consistency:

- Improved markers of muscle oxidation.

- Increased time to exhaustion in sustained efforts.

- Better tolerance to altitude training or low-oxygen conditions.

What the evidence doesn't show:

- Increased maximum strength. Not ergogenic for sprints, short lifts, or explosive efforts.

- Immediate effect comparable to a caffeine pre-workout. Cordyceps needs weeks of consistent use for physiological markers to shift.

- Consistent results in already highly trained athletes. Most measurable improvements appear in subjects with moderate baseline.

Which sports it makes sense for

Pull all of that together and the profile is fairly clear. Cordyceps fits if your main activity involves:

- Sustained moderate to high intensity efforts longer than 20 minutes: trail running, road cycling, rowing, distance swimming, ski touring.

- Altitude training or oxygen-limited conditions.

- High-volume training blocks where recovery between sessions is the limiting factor.

It fits less if your main activity is:

- Strength lifting focused on maximum force.

- Sprints or events under 2-3 minutes.

- Skill sports where aerobic capacity isn't the deciding factor.

This doesn't mean you can't take it if you train in the gym. It means the return per euro and per milligram is probably higher in endurance profiles.

How runners tend to integrate it

Patterns that repeat among runners and triathletes who've used it for a while:

- Daily, not cycled. Cordyceps doesn't generate tolerance or dependence, so the typical "8 weeks on, 4 off" pre-workout pattern doesn't apply. The accumulation is where the benefits live.

- Independent of training time. Since it's not a stimulant, it doesn't matter if you take it before, during, or after. Consistency matters.

- Combined with sensible training. Cordyceps doesn't compensate for poorly periodized volume or insufficient rest. It's a margin, not a fix.

- In modest, constant amounts. Doses used in studies range from 1 to 4 grams of extract daily. More doesn't seem to add more.

Who it's not for

Some honest caveats:

- If you compete in sports with anti-doping testing, always check your federation's regulations. Cordyceps isn't on the WADA list, but some commercial preparations can carry contaminants. Buy brands with purity analysis available.

- If you take anticoagulants or have clotting disorders, talk to your doctor first. Cordyceps has modest effects on platelet aggregation.

- If you expect a result in a week, you're going to be frustrated. Give it 6-8 weeks before judging.