Cordyceps, Libido and Testosterone: What the Studies Actually Show

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Cordyceps

A concentrated 4:1 extract of Cordyceps militaris, derived from the fruiting body, that is, the mushroom itself and not the mycelium. Two vegetable capsules per day provide 1,800 mg of extract, in a bottle of 60 capsules for one month. GMO-free, gluten-free, lactose-free, and vegan.

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Cordyceps is first and foremost a parasitic fungus. In its wild form, Ophiocordyceps sinensis, long called Cordyceps sinensis, colonizes a caterpillar on the Himalayan highlands and grows out of its head in spring. A review by the laboratory team that has most extensively studied the subject notes that it has long been presented in Asia as a tonic for sexual and reproductive disorders.

The most cited source in the West is a 1998 review compiling Chinese and English literature: open or blinded trials, more than 2,000 patients across all indications, and activities "restoring sexual function." These older trials are not available in PubMed and their methodology cannot be verified: they explain the reputation, without confirming it.

The 2017 laboratory review acknowledges it: very few studies have examined the effect of cordyceps on the reproductive system, and, for traditional remedies in general, evidence on reproduction is rare and "too often unconvincing."

We searched PubMed by crossing cordyceps, cordycepin, Ophiocordyceps, Cs-4, Hirsutella sinensis and Paecilomyces hepiali with libido, sexual function, erectile function, testosterone, sperm and fertility. Over a hundred references came up, almost all on cells, animals or mushroom genetics.

The finding is clear: no randomized placebo-controlled trial was identified testing cordyceps alone on libido, erectile function or testosterone. We found no trials in women on sexual desire. The rare human data concern blends, athletes or infertile men, without a placebo group for some.

The level of evidence is an assessment by the editorial team (size, randomization, placebo, cordyceps alone or in combination). In the premature ejaculation trial, C. sinensis "C4" mycelium served as a comparison against sertraline, an antidepressant, with no cordyceps-specific effect in the abstract.

The most cited trial was conducted in Italy with cyclists. It did not measure libido, but the testosterone-to-cortisol ratio in saliva, a marker of overtraining, around two races.

This result warrants strong reservations. The placebo and mushroom phases succeeded each other in the same subjects without randomization, and measurements were taken during two different races, with different distances, elevation gains, and difficulty levels. With 7 people and two mushrooms taken together, it is impossible to attribute the effect to cordyceps rather than to reishi or training. And salivary testosterone tells us nothing about libido or erectile function.

The other trial is better designed and finds nothing on hormones. In 21 young active men followed for 14 weeks of training combining strength and interval work, a formula combining Rhodiola rosea and Cordyceps sinensis with other ingredients modified neither body composition, strength, nor blood markers compared to placebo. Cortisol decreased by 11% in both groups, and the authors report no other changes in hormonal profile. The abstract does not detail the cordyceps dose, and the combination again prevents isolating its role.

A trial published in Chinese in 2021 divided 90 infertile men into three groups of 30 over 12 weeks: a traditional Chinese medicine preparation in pills, Cordyceps sinensis at 1 g twice daily, or both. The overall efficacy rate reached 96.42% with the combination, 78.57% with cordyceps alone, and 63.33% with the pills, and the proportion of progressively motile sperm increased by 30.05%, 24.74%, and 22.71%. The trial had no placebo group, and the abstract specifies neither the cordyceps preparation nor the definition of "efficacy rate." Lacking a DOI, it is cited without a number.

Other data on human sperm come from the laboratory, with cordycepin at 20, 100, and 500 µM added to sperm from healthy donors. The authors see potential for assisted reproductive technology; this result says nothing about a supplement taken orally.

In case of difficulty conceiving, couple assessment, with a semen analysis, remains the first step, before any supplement.

Testosterone is produced by Leydig cells of the testes, under the command of the luteinizing hormone. A Taiwanese team studied the effect of cordyceps on these mouse cells for over ten years.

In purified mouse Leydig cells, an extract of C. sinensis increased testosterone production in a dose-dependent manner, with a maximum at 3 mg/mL after 3 hours. Two of its fractions did the same, but not the soluble polysaccharide fraction. Pure cordycepin, tested from 10 µM to 5 mM, tripled testosterone production at a concentration of 1 mM, via adenosine receptors and the cyclic AMP pathway.

These results have their limitations, which the same team emphasizes. In normal Leydig cells, cordyceps inhibited testosterone production stimulated by human chorionic gonadotropin, a hormone that mimics luteinizing hormone, and, according to unpublished data from the team, plasma testosterone decreases in mice receiving both. The authors conclude that cordyceps could have an unfavorable effect in individuals whose hormonal axis functions normally, and that its use should first take into account each person's testosterone level.

Animal studies are more numerous and generally point in the same direction. In mice, a mycelium of C. sinensis increased plasma testosterone in 3 to 7 days, with no notable effect on the weight of reproductive organs. In 90 rats, a diet containing 1% or 5% of C. militaris mycelium for 6 weeks increased sperm count and motility, testosterone and estradiol, without changing luteinizing hormone or prolactin.

Their scope is limited: animals are often sick or weakened (induced diabetes, aging, castration), the doses and preparations do not translate directly to humans, and none have been reproduced in humans.

Several common claims therefore do not hold up. One cannot say that cordyceps increases testosterone in humans : the only human signal comes from a trial of 7 cyclists without randomization, with a mixture, and the available controlled trial finds no hormonal change. One cannot say that it improves libido or erectile function : no human trial measuring these parameters with cordyceps alone has been identified. One cannot say that it improves fertility : the only trial in infertile men had no placebo.

The direction of the effect is not even assured. The team that has studied Leydig cells most extensively observes that cordyceps inhibits the response to human chorionic gonadotropin in normal cells, and cordycepin reduces a key protein in steroid production in human ovarian cells. A review in the Singapore Medical Journal on the supposed hormonal activity of Chinese remedies concludes that ginseng and cordyceps show some glucocorticoid-type activities in vitro, but that clinical data to confirm them are lacking.

This also applies to our Cordyceps, a 4:1 concentrated extract of C. militaris carpophore of which two capsules provide 1,800 mg of extract: none of the cited trials addressed this product, and none of the studied doses match it. It can find its place within a mycotherapy approach, provided that no effect on sexuality is expected that human studies have not demonstrated. For athletic performance, human data are more abundant, as shown in our article on cordyceps and athletic performance.

If cordyceps acts on hormones, this is not necessarily good news for everyone, particularly for the prostate, an organ sensitive to testosterone. In rats, cordycepin at 5 and 10 mg per kilogram prevented testosterone-induced prostate enlargement, as did an extract of C. militaris carpophore. These animal results do not translate to humans, and, as Leydig cells demonstrate, the direction of cordyceps' hormonal effect is not assured: caution is warranted. In case of prostate disease, hormonal treatment, or elevated prostate-specific antigen levels, cordyceps should be discussed with your doctor.

Other precautions stem from its known effects. An extract of C. militaris mycelium enriched in cordycepin inhibited platelet aggregation and clot formation in rats and mice: a reason to seek medical advice when taking anticoagulants or antiplatelet agents. It is used in China as an adjunct to immunosuppression after kidney transplantation (5 trials, 447 patients, uncertain quality): a reason not to combine it without medical advice with an immunosuppressant or in case of autoimmune disease. Finally, contaminations have been published: two lead poisonings in Taiwan, with up to 20,000 ppm of lead in a cordyceps powder, and a thyroid crisis in a 70-year-old man taking cordyceps and another preparation containing levothyroxine.

Ginseng, Panax ginseng, is the most studied plant against placebo for erectile dysfunction. Several meta-analyses converge on a weak effect, of limited certainty, with often small trials.

Eight of these nine trials used Korean red ginseng, from 800 to 3,000 mg per day, most often 1,800 mg. A 2008 review found already, in 349 men, a favorable effect (relative risk of 2.40), with low-quality trials. A meta-analysis of 24 trials on plant-based supplements, published in Drugs in 2018, found for ginseng, from 5 trials and 399 men, an improvement in erectile function score (effect size of 0.43, i.e., a small to medium effect). A meta-analysis of 14 trials on various plants, published in 2026, found for ginseng, from only 4 trials, small improvements in erectile function, orgasm and desire, and blood testosterone barely higher.

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Red ginseng

Red ginseng, Panax ginseng, standardized in rare ginsenosides Rg3, Rg5 and Rk1, from roots cultivated indoors, soil-free and pesticide-free. Two vegetable capsules per day provide 200 mg of root extract.See Red Ginseng

The comparison with the trials must remain honest: they used Korean red ginseng at 800 to 3,000 mg per day, a preparation and doses different from our

Red Ginseng , a standardized extract in rare ginsenosides provided at 200 mg per day. Their results cannot therefore be attributed to it. It is reserved for adults and not recommended during pregnancy, breastfeeding and under antidiabetic treatment; under any other treatment, medical advice is essential. Ourcomplete ginseng guide details its other uses. For tribulus, the two trials in the 2018 meta-analysis were mixed; an analysis published in Nutrients in 2023 identifies ginseng, tribulus and L-arginine among the ingredients capable of improving male sexual function, but judges that 80% of the 25 supplements analyzed showed no expected efficacy. Our article on

tribulus and libido details these trials. Our Male Libido combines tribulus and ginseng: if you take it with Red Ginseng, account for the cumulative ginseng. associe tribulus et ginseng : si vous le prenez avec le Ginseng rouge, tenez compte du cumul de ginseng.

For erectile function, the strongest evidence does not come from mushrooms. A meta-analysis of 11 randomized trials shows thataerobic physical activity improves erectile function score by 2.8 points out of 30 on average compared to no exercise, and even more so when dysfunction is marked: 2.3 points for mild dysfunction, 3.3 for moderate dysfunction, and 4.9 for severe dysfunction. Our guide tofoundational endurance explains how to structure these sessions.

Type 5 phosphodiesterase inhibitors, such as sildenafil or tadalafil, remain the reference medication treatment. A network meta-analysis of 82 trials and 47,626 patients compared their efficacy and tolerability: sildenafil at 50 mg was most effective, tadalafil at 10 mg best tolerated. These medications are dispensed by medical prescription.

This trial only included men whose testosterone was genuinely low and symptomatic: it does not justify taking testosterone without prescription, nor seeking to "boost" a normal level. Desire also depends on sleep, stress, mood, and relationships: our article on cortisol and stress and the one on vitamin D deficiency address two factors often checked during an assessment.

A meta-analysis of 12 prospective cohorts and 36,744 men finds in those who suffer from it a cardiovascular disease risk multiplied by 1.48, coronary disease by 1.46, stroke by 1.35, and death from all causes by 1.19, even after accounting for classical risk factors. Another meta-analysis of 14 studies and 92,757 participants finds a cardiovascular event risk multiplied by 1.44, more pronounced in younger men. These are associations, not a demonstrated cause-and-effect relationship, but they make persistent dysfunction a good reason to have your heart checked.

For testosterone, clinical practice guidelines published in 2018 in The Journal of Clinical Endocrinology and Metabolism only retain a diagnosis of deficiency in a man who presents symptoms and whose testosterone is clearly and persistently low, based on a total testosterone test done in the morning while fasting, then repeated. They advise against testosterone treatment in men seeking to conceive in the short term.

If you wish to try cordyceps as part of a mycotherapy approach, as practical advice and not as a study result: our Cordyceps is taken at a rate of two capsules per day, in the morning or 30 to 60 minutes before exercise, in a course of at least 30 days, respecting the precautions detailed above.

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