Cordyceps
Cs-4 fermented mycelium (Cordyceps sinensis), 333 mg capsules; or cultivated C. militaris extract standardised to declared cordycepin (≥2.5 mg/g) and beta-glucans (≥150 mg/g). Never a 'mushroom blend' where the cordyceps dose is unknowable.
Early
First results, or a theory about how it works
Five small human trials, none at low risk of bias, mostly unregistered, several using multi-ingredient blends. The one positive signal (threshold) is a lab measure a wearable cannot see; VO2max was explicitly unchanged.
In the one decent study, healthy adults aged 50 to 75 could work about 10% harder before tiring after 12 weeks, but their overall fitness did not change.
In the only decent trial, 12 weeks of Cs-4 raised metabolic threshold 10.5% (0.83→0.93 L/min, p<0.02) and ventilatory threshold 8.5% in healthy 50-75 year-olds — but VO2max did not change at all.
Proposed improvement in oxygen utilisation and mitochondrial ATP turnover, shifting the ventilatory/lactate threshold upward without raising maximal oxygen uptake.
Untrained or older adults working at submaximal intensities. Trained athletes showed nothing in the 16-week runner trial.
We compare each effect with how much that number normally swings from one night to the next. An effect smaller than the swing is real, but you will not see it in a week of data.
- VO2maxToo small to seeeffect: 0 mL/kg/minnormal swing: ±1.2 mL/kg/min
What to buy
- ✓Cs-4 fermented mycelium (Cordyceps sinensis), 333 mg capsules; or cultivated C. militaris extract standardised to declared cordycepin (≥2.5 mg/g) and beta-glucans (≥150 mg/g). Never a 'mushroom blend' where the cordyceps dose is unknowable.
- ✓1 g/day Cs-4 (333 mg × 3) with food; C. militaris trials used 1-4 g/day.
- ✓Third-party tested (USP, NSF, Informed Sport)
- ✕Proprietary blends that hide the dose per ingredient
- ✕Unstandardised extracts with no active-compound percentage
- · Wild Cordyceps sinensis is routinely adulterated and has documented heavy-metal (lead, arsenic) contamination — only cultivated C. militaris or Cs-4 fermentate is acceptable.
- · GI upset and dry mouth are the most commonly reported effects in trials.
- · No human safety data beyond ~16 weeks; none of the five C. militaris trials was at low risk of bias.
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One of the few that prints its beta-glucan content instead of a vague 'mushroom blend'. If the label will not tell you how much active material is in there, you cannot dose it.
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The cheapest per capsule of the single-species options, in a count that covers the full 1 g/day for months.
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US-grown, single species, organic certified — the best-rated of the three. Cordyceps is graded emerging here: the VO2max signal is real but small and inconsistent.
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See all on AmazonEvery result, next to the line that means no effect
Each diamond is a study's best estimate. The thin line shows how sure the study was: the shorter the line, the more certain the result.
- Metabolic threshold% vs baseline · Chen 2010, J Altern Complement Med+10.5[not given]
- Ventilatory threshold% vs baseline · Chen 2010, J Altern Complement Med+8.50[not given]
- VO2maxmL/kg/min · Chen 2010 — 'no changes' in either group0.00[not given]
- Peak exercise VO2 (acute 1 g)L/min (p=0.49) · Farzan 2026, PLOS ONE0.00[not given]
Each unit gets its own scale, so numbers are never mixed on one line. When a study gave no range, we leave it blank instead of inventing one.
3 studies over 16 years
The studies
- 1.Effect of Cs-4 (Cordyceps sinensis) on Exercise Performance in Healthy Older Subjects: A Double-Blind, Placebo-Controlled TrialThe Journal of Alternative and Complementary Medicine · 2010 · rct · 1 experiments · n = 20
1 g/day Cs-4 for 12 weeks raised metabolic threshold 10.5% (p<0.02) and ventilatory threshold 8.5%; VO2max unchanged in both groups.
- 2.Current Evidence of Ergogenic and Post-Exercise Recovery Effects of Dietary Supplementation with Cordyceps militaris in Humans — A Narrative ReviewNutrients · 2026 · systematic review · 5 experiments · n = 321
Findings inconsistent across five trials; no study at overall low risk of bias (four high, one moderate), most unregistered and using multi-ingredient products.
- 3.Acute Cordyceps militaris supplementation and elevated resting oxygen uptake with faster reaction times: A randomized crossover trialPLOS ONE · 2026 · crossover · 1 experiments · n = 12
1 g pre-exercise raised resting VO2 (0.37 vs 0.24 L/min, p=0.022) and cut post-exercise reaction time 70 ms (p=0.042), but peak exercise VO2 was unchanged (p=0.49).
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