cordyceps

Cordyceps is a genus of fungi — most commonly the wild Cordyceps sinensis (also called Ophiocordyceps sinensis) and the cultivated Cordyceps militaris — that in nature grow on insect larvae. It has been used for centuries in traditional Chinese medicine and is now sold as a dietary supplement in capsules, powders, and liquid extracts, frequently marketed as an "adaptogen" or energy aid.

High-quality human evidence for Cordyceps is weak. The NIH LiverTox monograph states that none of the purported benefits of Cordyceps have been demonstrated in human clinical trials, and reports that controlled trials have generally not shown a meaningful benefit over placebo for outcomes such as exercise performance. The major US consumer-health authorities (NIH Office of Dietary Supplements, NCCIH's "Herbs at a Glance," and MedlinePlus) do not publish a dedicated fact sheet evaluating its effectiveness. For now, popular claims that it boosts energy, athletic performance, or immunity should be treated as unproven and based largely on traditional use and preliminary laboratory or animal studies.

There is no established or government-recommended dose for Cordyceps. Products differ widely in the species used (wild C. sinensis versus cultivated C. militaris or mycelium) and in how they are prepared, so strength varies between brands. Because the FDA does not review supplements for effectiveness before they are sold, it is sensible to talk with your doctor or pharmacist before starting Cordyceps — especially if you are pregnant or breastfeeding, have a health condition, or take prescription medicines.

According to the NIH LiverTox monograph, Cordyceps extracts are generally well tolerated, are considered "generally recognized as safe" (GRAS) by the FDA, and have not been linked to liver enzyme elevations or clearly documented liver injury — though a single case report described liver-vessel scarring (hepatoportal sclerosis) in a long-term user that improved after stopping. More broadly, the FDA does not test supplements for safety and effectiveness the way it does medicines, and product quality can vary, with some products mislabeled or contaminated. People who are pregnant or breastfeeding, who have a bleeding or autoimmune condition, or who are scheduled for surgery should be especially cautious and check with a clinician first. Choosing products independently tested by a group such as USP or NSF may lower the risk of contamination or mislabeling, though it does not guarantee the supplement works.

Human safety data remain limited. The NIH LiverTox monograph lists uncommon, generally mild side effects including abdominal discomfort, diarrhea, dry mouth, nausea, poor appetite, and rash. As with any supplement, allergic reactions are possible — stop use and seek medical care if you notice rash, swelling, or trouble breathing.

No authoritative US government source documents specific drug interactions for Cordyceps, and well-controlled interaction studies are lacking — so any interaction risk is unconfirmed. As a general precaution with any supplement, tell your doctor and pharmacist about Cordyceps and everything else you take, particularly if you use blood thinners, diabetes medicines, or drugs that affect the immune system, so they can watch for unexpected effects.