Ask what these two do and you'll get the same word twice: energy. Read the trials and neither one measured anything a tired person would recognise. Cordyceps raised the threshold at which lactate starts accumulating by 10.5% and left maximum oxygen uptake completely unchanged. Reishi cut fatigue scores by 28.3% — in 132 patients carrying a clinical diagnosis of chronic fatigue and weakness. Those are two real results about two different things, and "energy" isn't either of them.
Cordyceps's best-known human trial gave 20 healthy adults aged 50–75 either 333 mg of Cs-4 three times daily — 1 gram a day — or placebo for 12 weeks. Metabolic threshold rose 10.5%, from 0.83 to 0.93 L/min (p < 0.02), and ventilatory threshold rose 8.5%. VO2 max didn't change in either group. A separate three-week study of a 4 g/day mushroom blend containing Cordyceps militaris in 28 young adults did move VO2 max (+4.8 ml/kg/min, p = 0.042) and time to exhaustion (+69.8 s) — but it tested a blend, not cordyceps alone. Reishi's fatigue evidence comes from 132 neurasthenia patients on 1,800 mg three times daily for eight weeks, where the sense of fatigue fell 28.3% from baseline against 20.1% on placebo, and from 48 breast cancer patients whose fatigue and quality-of-life scores improved over four weeks.
So which one do you buy? It depends entirely on whether your problem is capacity or exhaustion — and those want opposite products.
What Did the Cordyceps Trial Actually Measure?
Thresholds, not maximums, and the distinction is the whole result.
Chen's 2010 double-blind trial enrolled 20 healthy adults aged 50 to 75 and ran maximal incremental cycle testing with breath-by-breath analysis at baseline and after 12 weeks of 333 mg Cs-4 three times a day. Metabolic threshold — the workload above which lactate begins to accumulate — rose from 0.83 to 0.93 L/min, a 10.5% increase at p < 0.02. Ventilatory threshold rose 8.5%.
VO2 max didn't budge, in either arm. The placebo group showed no significant change in either threshold.
Read plainly, that says cordyceps didn't raise the ceiling; it raised the point at which sustained effort starts to hurt. For a cyclist or a hiker that's arguably the more useful number, and our endurance article unpacks why. For someone who's tired at their desk, it's irrelevant.
Didn't Another Study Raise VO2 Max?
It did, and the fine print matters.
Hirsch's 2017 study gave 28 young adults 4 g a day of a mushroom blend containing Cordyceps militaris or maltodextrin. After one week, nothing reached significance on any measure. After three weeks, VO2 max improved by 4.8 ml/kg/min in the mushroom arm against 0.9 in placebo (p = 0.042), with time to exhaustion up 28.1 s at one week and 69.8 s at three.
Two caveats. Only ten volunteers continued to the three-week point, and the product was a blend — so the result belongs to the blend, not to cordyceps in isolation. It's a genuine finding that cannot be cleanly attributed to the species on the label.
What Does Reishi Do Instead?
It reduces fatigue in people who have a fatigue problem. That's a narrower claim and a better-supported one.
Tang's 2005 trial randomised 132 patients diagnosed with neurasthenia — an ICD-10 condition of chronic fatigue and weakness — to a Ganoderma lucidum polysaccharide extract at 1,800 mg three times daily or placebo for eight weeks. Sense of fatigue fell 28.3% from baseline against 20.1% on placebo; 51.6% of the treatment group were rated more than minimally improved against 24.6%.
Zhao's 2012 pilot gave Ganoderma lucidum spore powder to breast cancer patients on endocrine therapy. Over four weeks the treated group showed improvements in physical well-being and the fatigue subscale, reported less anxiety and depression and better quality of life, and had significantly lower TNF-α and IL-6. Forty-eight patients, no serious adverse effects.
Notice what's absent from both: any healthy participant. Reishi's fatigue evidence lives entirely in clinical populations.
How Do They Compare Head to Head?
| Cordyceps militaris | Reishi | |
|---|---|---|
| What improved | Lactate and ventilatory thresholds | Fatigue scores, mood, quality of life |
| Best single number | +10.5% metabolic threshold | −28.3% fatigue vs −20.1% placebo |
| VO2 max | Unchanged in the 12-week trial | Not measured |
| Who was studied | Healthy adults 50–75; young adults on a blend | Neurasthenia patients; breast cancer patients |
| Studied dose | 1 g/day Cs-4, or 4 g/day blend | 1,800 mg three times daily |
| Time to effect | Three weeks minimum; 12 weeks in the main trial | Four to eight weeks |
| Best time to take | Before training | Evening, for its sleep and stress profile |
| Main caution | Autoimmune conditions, immunosuppressants | Antiplatelet activity; stop before surgery |
Which One Should a Tired Person Buy?
Honestly? Possibly neither, and that's worth saying before either product goes in a basket.
No trial has recruited a healthy adult who's simply tired and measured what happens. Cordyceps's population was already exercising hard enough to have a measurable lactate threshold. Reishi's populations had diagnoses. Ordinary tiredness — poor sleep, high load, too much caffeine too late — has never been the subject of a trial of either species.
If you're going to pick one anyway, pick by the shape of the problem. Tiredness that comes with sleep trouble and a high stress load points toward reishi, which is the direction our stress ranking ends up pointing too. Tiredness that shows up in the third hour of a long ride points toward cordyceps.
Can You Take Both?
Yes, and the timing more or less separates itself. Cordyceps belongs before training; reishi belongs in the evening, where its sedative-leaning profile is a feature rather than a nuisance. Our cordyceps timing guide and reishi timing guide cover each separately.
One real caution applies to the pair rather than either alone: reishi shows antiplatelet activity in laboratory screening, so both should be stopped two weeks before any procedure — see mushroom supplements before surgery.
What Should You Actually Do?
- Training endurance? Cordyceps, at 1 g a day, for at least 12 weeks. That's the protocol that produced the threshold result — see our dosage guide.
- Fatigue with a clinical shape? Reishi. Both of its trials recruited diagnosed populations, and both reported meaningful improvement.
- Don't expect cordyceps to raise your ceiling. VO2 max didn't move in the 12-week trial, and the study that did move it tested a blend.
- Don't expect reishi to add energy. It reduced fatigue in fatigued people; nobody has shown it does anything for someone who isn't.
- Fix sleep before buying either. Neither species has a trial in ordinary sleep-deprived adults, which is most people asking this question.
- If you want a stimulant effect, be honest about that. Our cordyceps versus caffeine comparison sets out what each actually does.
The Honest Summary
These two aren't competitors. Cordyceps produced a submaximal efficiency gain in older adults over 12 weeks and did not change maximum capacity. Reishi produced symptom relief in people with diagnosed fatigue and has never been tested in anyone healthy.
Both results are real and both are narrower than the shelf implies. The trap is the shared word on the front of the pack, which invites a tired person to buy either one and expect a lift neither has ever demonstrated. Pick by mechanism — threshold or fatigue — and the choice makes itself.
Frequently Asked Questions
Which is better for energy, cordyceps or reishi?
Neither has been tested for energy in a healthy tired adult. Cordyceps raised the lactate threshold 10.5% in trained-capacity older adults; reishi cut fatigue scores 28.3% in patients with a clinical fatigue diagnosis. Different problems, different products.
Does cordyceps increase VO2 max?
Not in the 12-week trial, where it was explicitly unchanged in both groups. A three-week study did report +4.8 ml/kg/min, but tested a 4 g/day mushroom blend rather than cordyceps alone, with only ten participants completing that arm.
How long does cordyceps take to work?
Three weeks at minimum. One week of supplementation produced no significant change on any measure in the blend study, and the threshold result came after 12 weeks at 1 g a day.
Is reishi good for tiredness?
In diagnosed fatigue, yes. Across 132 neurasthenia patients, fatigue fell 28.3% from baseline against 20.1% on placebo over eight weeks, and 51.6% were rated more than minimally improved against 24.6%. No trial has recruited healthy tired adults.
Can I take cordyceps and reishi together?
There's no documented interaction, and the timing separates naturally — cordyceps before training, reishi in the evening. Stop both two weeks before surgery, since reishi shows antiplatelet activity in laboratory testing.
Shop Cordyceps and Reishi
Cordyceps capsules (120 caps €49) make the 1 g daily figure easy to hit, and dried Cordyceps militaris (100 g €49, 500 g €199) is the cheaper route for longer courses. Reishi capsules (120 caps €39, 2 × 120 €70) suit evening dosing, and Reishi tincture (50 ml €49) covers the alcohol-soluble triterpenes. Browse Cordyceps. Free shipping on orders over €50.
Related Articles
- Cordyceps vs Caffeine for Energy
- Cordyceps for Endurance: Oxygen Use and ATP
- Reishi: Stress and Sleep Guide
- Cordyceps Dosage Guide
- Reishi Dosage Guide
- Best Mushrooms for Energy Without Caffeine
- Best Mushrooms for Athletes
Sources
- Chen S, Li Z, Krochmal R, Abrazado M, Kim W, Cooper CB. Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: a double-blind, placebo-controlled trial. J Altern Complement Med. 2010;16(5):585-590. PubMed 20804368
- Hirsch KR, Smith-Ryan AE, Roelofs EJ, Trexler ET, Mock MG. Cordyceps militaris improves tolerance to high-intensity exercise after acute and chronic supplementation. J Diet Suppl. 2017;14(1):42-53. PubMed 27408987
- Tang W, Gao Y, Chen G, et al. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. J Med Food. 2005;8(1):53-58. PubMed 15857210
- Zhao H, Zhang Q, Zhao L, Huang X, Wang J, Kang X. Spore powder of Ganoderma lucidum improves cancer-related fatigue in breast cancer patients undergoing endocrine therapy: a pilot clinical trial. Evid Based Complement Alternat Med. 2012;2012:809614. PubMed 22203880
- Poniedziałek B, Siwulski M, Wiater A, et al. The effect of mushroom extracts on human platelet and blood coagulation: in vitro screening of eight edible species. Nutrients. 2019;11(12):3040. PubMed 31842490