I’ll admit cordyceps has one of the stranger origin stories in the supplement world. This is a fungus that infects caterpillar larvae, essentially mummifying them from the inside out, then sprouts a fruiting body from the head. If that sounds like something from a horror film, you’re not wrong. It’s also been used in traditional Chinese medicine for over 700 years, which gives you a sense of how long humans have been willing to overlook the creepy factor when something might actually work.

Wild cordyceps (Cordyceps sinensis) grows at high altitudes in the Tibetan Plateau, primarily in China’s Qinghai and Tibet regions. The harvesting conditions are genuinely treacherous, and combined with limited supply, prices have reached absurd levels. We’re talking somewhere between $20,000 to $40,000 per kilogram for the wild stuff. This has earned it nicknames like “soft gold” and, rather more colourfully, “Himalayan Viagra.”

The good news is that most supplements today use cultivated cordyceps mycelium grown through fermentation. This brings the cost down dramatically while maintaining a similar chemical profile. Whether it’s quite as potent as wild-harvested cordyceps is debated, but at least it’s affordable enough to actually study.

What exactly is cordyceps?

Cordyceps sinensis belongs to the Ascomycetes class of fungi. It parasitises the larvae of ghost moths, gradually replacing the larval tissue with fungal mycelium. By winter, the larva has essentially become a fungal mass (“winter worm”). Come spring, a club-shaped fruiting body emerges from where the head was (“summer grass”). The Chinese name literally translates to “winter worm, summer grass.”

The fungus contains a mix of bioactive compounds that researchers have been picking apart for decades. These include:

Polysaccharides, which seem to be responsible for many of the immune-modulating effects
Cordycepin (3’-deoxyadenosine), a nucleoside analogue with potential anti-inflammatory properties
Mannitol, sometimes called cordycepic acid
Ergosterol, a precursor to vitamin D2
Various amino acids and trace elements

Modern fermentation technology has made it possible to cultivate cordyceps mycelium at scale. Studies comparing cultivated and wild strains suggest they have similar chemical profiles, though the ratios of active compounds can vary depending on growing conditions.

What does the research actually show?

I’ve gone through the clinical literature on cordyceps, and here’s my honest assessment. There’s promising research in several areas, but much of it comes from small trials or studies with methodological limitations. The strongest evidence exists for lung and kidney conditions, which aligns with cordyceps’ traditional use in Chinese medicine.

1. May help with heart arrhythmias

Arrhythmias occur when the heart’s electrical system misfires, causing beats that are too fast, too slow, or irregular. About half of heart disease deaths involve arrhythmias, so finding treatments that help without excessive side effects matters.

A 2021 meta-analysis looked at 13 randomised controlled trials involving 1,379 patients with arrhythmias. The trials compared standard anti-arrhythmic drugs alone versus the same drugs combined with Ningxinbao capsules (a cordyceps mycelium preparation). The combination group showed better results on electrocardiogram readings and heart rate improvements, particularly for patients with bradycardia. Adverse reactions were also lower in the cordyceps group, suggesting it might help reduce the toxicity burden of conventional arrhythmia drugs (PubMed).

That said, the included studies had quality limitations, and this research comes predominantly from China. Independent replication would strengthen the findings.

2. Shows promise for chronic obstructive pulmonary disease (COPD)

COPD is a progressive lung disease that makes breathing difficult. It’s one of the leading causes of death worldwide, primarily caused by smoking and environmental pollutants. Current treatments slow progression but don’t reverse the damage.

A 2019 systematic review examined 13 studies with 1,092 patients who had stable, moderate-to-severe COPD. Cordyceps preparations appeared to improve lung function, exercise tolerance, quality of life, and symptom burden (PMC). The mechanism might involve anti-inflammatory effects in the airways, though this needs more investigation.

This is one of the more compelling areas for cordyceps research, partly because it aligns with centuries of traditional use for respiratory complaints. However, sample sizes remain small, and publication bias is a concern.

3. Potential benefits for chronic kidney disease

Chronic kidney disease affects kidney function progressively and often accompanies diabetes and high blood pressure. It’s the 18th leading cause of death globally, and for most patients, cardiovascular complications pose a greater risk than progressing to dialysis.

A Cochrane review, generally considered the gold standard for evidence synthesis, analysed 22 randomised controlled trials with 1,746 non-dialysis kidney disease patients. Cordyceps preparations used alongside conventional treatment reduced serum creatinine levels, increased creatinine clearance, and decreased proteinuria. They also helped with common complications like anaemia and low serum albumin (PubMed).

The Cochrane authors noted the evidence quality was low, so these findings should be considered preliminary. Still, the consistency across multiple trials suggests something worth investigating further.

4. May support kidney transplant outcomes

Kidney transplant patients face a delicate balancing act: immunosuppressant drugs prevent rejection but come with significant side effects, including increased infection risk, metabolic problems, and nephrotoxicity (ironically, toxicity to the new kidney itself).

A 2017 meta-analysis of 9 randomised trials with 907 transplant patients found that adding cordyceps to standard immunosuppressant regimens reduced the incidence of several complications: hyperuricaemia (elevated uric acid), hyperlipidaemia, hyperglycaemia, proteinuria, and liver injury. It also appeared to reduce the nephrotoxicity associated with immunosuppressant drugs (PubMed).

If confirmed, this would be genuinely useful since protecting a transplanted kidney from the drugs meant to save it is an ongoing clinical challenge.

5. Appears to modulate immune function

The immune system needs to mount responses against pathogens and cancer cells while avoiding overreaction that damages healthy tissue. Immunomodulators help fine-tune this balance.

An 8-week randomised, double-blind, placebo-controlled trial of 80 healthy adults found that cordyceps mycelium extract increased natural killer (NK) cell activity (PMC). NK cells are part of the innate immune system and play important roles in controlling viral infections and tumour surveillance.

The sample size here is small, so these results need replication. But the finding is consistent with the polysaccharide content of cordyceps, which has been shown in laboratory studies to stimulate various immune cells.

6. May benefit chronic hepatitis B

Hepatitis B affects roughly 400 million people worldwide and causes an estimated 750,000 deaths annually from complications like cirrhosis and liver cancer. Infected individuals have about a 100-fold increased risk of developing hepatocellular carcinoma.

A 6-month randomised trial with 60 chronic hepatitis B patients found that Ci’anbao capsules (containing cultivated cordyceps mycelium) reduced several liver function markers: ALT, AST, hyaluronic acid, type III procollagen, and laminin (PubMed). These markers indicate liver inflammation and fibrosis progression.

This is a single small trial, so it’s far from definitive. But hepatitis B management often involves decades of monitoring and treatment, so any adjunctive therapy that might slow liver damage warrants attention.

Side effects of cordyceps

For most healthy adults, cordyceps supplements appear well-tolerated at typical doses. Reported side effects tend to be mild gastrointestinal issues:

Diarrhoea
Constipation
Nausea
Dry mouth

Serious adverse events are rare in the published literature, though this partly reflects that most studies are short-term and involve selected patient populations.

According to the Mayo Clinic, cordyceps has been used safely in studies lasting up to a year, but long-term safety data remains limited.

Who should avoid cordyceps (11 contraindications)

Cordyceps isn’t suitable for everyone. The following groups should either avoid it entirely or consult their doctor before use:

Pregnant or breastfeeding women: There’s simply not enough safety data. Avoiding it is the sensible approach.
People with autoimmune conditions: Because cordyceps stimulates immune activity, it could theoretically worsen conditions like multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, Hashimoto’s thyroiditis, or Graves’ disease.
Those with bleeding disorders or on anticoagulants: Cordyceps may slow blood clotting. If you’re on warfarin, aspirin, clopidogrel, or similar medications, this interaction could increase bleeding risk.
People scheduled for surgery: Stop cordyceps at least two weeks before any surgical procedure to avoid bleeding complications.
Those taking cyclophosphamide: This chemotherapy drug’s effectiveness might be reduced by cordyceps.
People on immunosuppressants: Medications like cyclosporine, tacrolimus, azathioprine, or corticosteroids could have their effects counteracted by cordyceps’ immune-stimulating properties.
Anyone allergic to moulds or yeasts: Cordyceps is a fungus. If you’ve had allergic reactions to fungi, proceed with caution or avoid entirely.
Diabetics or those on blood sugar medications: Cordyceps may lower blood glucose, which could cause hypoglycaemia when combined with diabetes medications like insulin or metformin. Blood sugar monitoring becomes more important.
Those taking MAO inhibitor antidepressants: A potential interaction that could reduce the medication’s effectiveness.
People on antiviral medications: There may be interactions affecting drug efficacy.
Before laboratory blood tests: Cordyceps might interfere with certain test values. Inform your healthcare provider about any supplements you’re taking.

Dosage and forms

Cordyceps supplements come in several forms:

Capsules or tablets: Typically 500-1500mg per day, divided into doses
Powders: Can be added to drinks or food
Liquid extracts: More concentrated, requiring smaller amounts

There’s no officially established dose, and optimal amounts likely vary by condition and preparation type. Most studies use proprietary formulations, making direct comparisons difficult.

The NHS recommends discussing any supplement use with your GP, particularly if you have existing health conditions or take medications.

The bottom line

Cordyceps has some genuinely interesting research behind it, particularly for respiratory and kidney conditions. The evidence isn’t strong enough to replace conventional treatment, but it might have a role as adjunctive therapy for certain patients.

If you’re considering cordyceps, the usual caveats apply: buy from reputable manufacturers who test for contaminants, start with lower doses, and pay attention to how your body responds. Given the potential drug interactions, discussing it with your healthcare provider first is worthwhile, especially if you have any of the conditions mentioned in the contraindications list.

For those interested in other adaptogens and immune-supporting supplements, you might also want to read about ginseng, astaxanthin, or Indian ginseng (ashwagandha). If kidney health is your specific concern, our guide to chronic kidney disease-related conditions may also be helpful.