Cordyceps

What it is

Cordyceps is a group of fungi used in traditional Chinese medicine. The best known, Cordyceps sinensis (also called Ophiocordyceps sinensis or caterpillar fungus), grows on insect larvae in the Himalayas and is very costly [1]. Most supplements use lab-grown Cordyceps militaris or fermented mycelium (the fungus's root-like body) from related strains, which are different products from the wild fungus [2] [3]. Compounds of interest include cordycepin, adenosine and polysaccharides (long sugar chains) [4].

How it might work

Proposed, not proven in people: cordyceps polysaccharides and cordycepin may activate immune cells such as NK cells and change cytokine (immune signalling protein) levels [2] [4]. In one small trial, it appeared to speed up the arrival of stem cells to exercised muscle [5].

What the research says

Lung cancer treatment (as an add-on). A 2024 meta-analysis (a study that pools many trials) of 12 randomised trials with 928 lung cancer patients found that adding Cordyceps sinensis to standard treatment improved tumour response (RR 1.17, 95% CI 1.05 to 1.29), raised CD4 and NK immune cell levels, improved quality of life on the Karnofsky scale (+8.2 points) and cut the risk of low blood counts from chemotherapy (myelosuppression RR 0.38) and radiation lung inflammation (RR 0.74) [6]. The abstract does not report survival.

Kidney function. A Cochrane review (an independent review of trials) of 22 trials with 1,746 people with chronic kidney disease found cordyceps preparations lowered serum creatinine by about 61 µmol/L (95% CI −86 to −36), raised creatinine clearance by 9.2 mL/min and cut protein in urine by 0.15 g a day, but the trials were of low quality and the reviewers could not reach firm conclusions [1]. A 2023 meta-analysis of 38 trials with 3,167 people with diabetic kidney disease found lower creatinine (−11.5 µmol/L) and urine albumin when cordyceps was added to standard ACE inhibitor or ARB drugs; no trial measured kidney failure or heart events [7]. A 2024 analysis of 15 studies in 1,310 people with kidney dysfunction also reported lower creatinine [8]. In kidney transplant recipients, a Cochrane review of 5 small trials (447 people) found no difference in graft or patient survival compared with azathioprine, with some better lab values, and rated the evidence limited [9].

Lung disease (COPD). A meta-analysis of 27 trials of Bailing capsules, a fermented Cordyceps sinensis product, in people with COPD found better lung function (FEV1), a longer 6-minute walk and fewer acute attacks [10]. A 240-person trial comparing two cordyceps-based capsules found fewer attacks with Yong Chong Cao than with Bailing but no difference in lung function [11].

Immune function in healthy people. Three small trials point the same way. In 79 healthy Korean men, 1.5 g a day of Cordyceps militaris for 4 weeks raised NK cell activity, lymphocyte proliferation, IL-2 and interferon-gamma more than placebo [2]. In 79 healthy adults, a cordyceps mycelium extract (1.68 g a day for 8 weeks) raised NK cell activity by 38.8% over placebo [3]. A small trial of a fermented C. militaris drink found higher NK activity in men and women over 8 weeks [4]. These are blood markers, and none measured fewer infections.

Endurance and recovery. In 20 healthy older adults, 1 g a day of Cs-4 for 12 weeks raised the metabolic threshold (the effort level at which lactate builds up) by 10.5%, though VO2max did not change [12]. In 28 young adults, a 4 g daily mushroom blend containing C. militaris raised VO2max by 4.8 mL/kg/min versus 0.9 on placebo after 3 weeks and extended time to exhaustion by about 70 seconds [13]. A 2025 review concluded time to exhaustion improved with 2 to 16 weeks of cordyceps but effects on aerobic fitness were inconsistent [14]. A single 1 g dose before a cycling test made reaction times faster afterwards in 12 young men without changing peak oxygen uptake [15]. On recovery, a 14-person crossover trial found cordyceps reduced muscle cell damage after interval exercise [5], and in 22 long-distance runners an extract lowered creatine kinase, a marker of muscle injury, after 16 weeks and kept ferritin and haemoglobin up; the supplement was made by the company that supported the study [16].

Thinking and memory. In 96 healthy students, a combination of O. sinensis and Ganoderma lucidum for 30 days did not improve any cognitive domain [17].

Doses used in studies

Doses depend heavily on the product. Immune trials used 1.5 g a day of C. militaris for 4 weeks [2] and 1.68 g a day of a mycelium extract for 8 weeks [3]. The older-adult exercise trial used 333 mg three times a day for 12 weeks [12]. The lung cancer meta-analysis suggested 6 g a day over 21-day cycles gave the best tumour response [6]. Exercise trials used 1 g before a test [15] and 4 g a day of a mushroom blend for 3 weeks [13]. These are doses studied, not recommendations.

Safety and interactions

Side effects. Trials in healthy people reported no significant adverse reactions [2] [3], and a 3-month trial of 49 people taking 1.05 g a day of Cordyceps cicadae mycelium found no change in kidney or liver tests and no side effects [18]. In lung cancer patients, liver or kidney damage (RR 0.32, 95% CI 0.09 to 1.10) and stomach and bowel side effects (RR 0.80) were not clearly different from standard care alone [6]. Adverse events did not differ between groups in the diabetic kidney disease meta-analysis [7].

Medicines. No dedicated drug-interaction studies were found. Cordyceps has been tested alongside or instead of immunosuppressants in kidney transplant recipients, but the reviewers judged the studies too small and biased to conclude on safety [9]. Because it appears to stimulate immune markers [2], people who take immunosuppressant medicines or have autoimmune disease should ask a doctor first.

Upper limits, pregnancy and other conditions. No official upper intake limit was identified; the lung cancer trials pooled up to 6 g a day [6]. No data were found on use in pregnancy or breastfeeding, in people with bleeding disorders, or on contamination of wild cordyceps products. Most trial products are lab-grown strains, so findings may not apply to wild or unregulated products.

Caveats and open questions

Many trials are small and short, use named commercial products (Bailing capsule, Cs-4, mycelium extracts) and often come from China, so results may not carry over to a generic cordyceps capsule [10] [1]. The Cochrane reviews rated the kidney trials as high or unclear risk of bias [1] [9]. The diabetic kidney meta-analysis noted that no trial tracked kidney failure or heart events [7]. Several sports trials tested blends with other herbs or were funded by the product's maker [13] [16].