Cordyceps

What it is

Cordyceps refers to a group of parasitic fungi. Wild Ophiocordyceps sinensis grows on insect larvae in the Tibetan plateau and is extremely expensive. Most supplements use cultured mycelium or Cordyceps militaris, which is grown commercially.

People take it for energy, exercise endurance, libido and immune support. It is popular among athletes and in mushroom supplement blends.

It is sold as a food supplement in the UK. Products vary widely in what part of the fungus they contain and how strong they are.

How it works

Compounds such as cordycepin and polysaccharides may influence energy metabolism (ATP), oxygen use and immune signalling. These effects are mainly from lab and animal studies.

What the evidence says

• Limited Exercise capacity
  Small trials show modest gains in time to exhaustion or oxygen use in some groups, with other trials showing none.
• Weak Fatigue
  Mostly small studies and traditional use, so evidence is thin.
• Weak Libido and sexual function
  Animal and small human data; unproven.
• Weak Immune function
  Findings are mostly lab-based, with minimal human evidence.

Evidence ratings are our plain-English summary of how much good human research exists, not a promise of results. How we rate evidence.

Dosage and timing

• Typical supplement doses are 1 to 3 g daily of powder, or the stated dose of an extract.
• Take in the morning or before exercise, with food if it upsets your stomach.
• Dosing is poorly standardised between products, so follow the label.
• There is no NHS reference intake. Check current guidance.

Forms and what to look for

• Fruiting body extracts of Cordyceps militaris with stated cordycepin content are usually preferred.
• Mycelium grown on grain often contains lots of starch rather than active compounds.
• Wild Cordyceps sinensis is costly and often counterfeit.
• Check the label says fruiting body or mycelium and states the beta-glucan or cordycepin level.

What to expect, and when

• Exercise studies often run for one to three weeks.
• Any effect on energy may take several weeks to notice.
• Many people feel no difference; stop if nothing changes after two months.

Side effects

• Stomach upset, dry mouth or nausea.
• Diarrhoea in some people.
• Allergic reactions to fungi.
• Rarely, increased bleeding tendency.

Interactions

• Blood thinners such as warfarin: possible additive effect.
• Immunosuppressants: cordyceps may stimulate immune activity.
• Diabetes medicines: potential effect on blood sugar.
• Hormonal therapies: limited data.

Who should avoid it

• People with autoimmune conditions or taking immunosuppressants.
• Anyone with bleeding disorders or due for surgery.
• Pregnant or breastfeeding women.
• People with mushroom or mould allergies.

Risks and safety

• Wild cordyceps has had heavy metal contamination (including arsenic) reported.
• Counterfeit or mislabelled products are common.
• Not WADA-prohibited, but athletes should use batch-tested products.

Buying well: quality and testing

• Look for the species and part used (fruiting body or mycelium).
• Check for beta-glucan or cordycepin content.
• Prefer third-party tested products.
• Avoid vague mushroom blends with no amounts.

Bottom line

Cordyceps is a popular mushroom supplement with modest and inconsistent evidence. It may suit people who want a low-key trial for stamina, but expect little. Be extra careful with autoimmune conditions, immunosuppressants and blood thinners.