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Short answer: Cordyceps is a group of fungi that grow on insects. The species most used in traditional Chinese medicine, Ophiocordyceps sinensis, grows on moth caterpillars, while a related "zombie-ant fungus" takes over carpenter ants and inspired the fungus in The Last of Us. Cordyceps cannot turn people into zombies: most fungi cannot grow at human body temperature. As a supplement, it is used for energy and stamina, but exercise studies are mixed. No major side effects have been reported, though it may lower blood sugar and increase bleeding risk with certain medicines.
If you have watched The Last of Us, you might be surprised to see cordyceps in coffee blends and capsules. Here is what cordyceps really is in nature, why it cannot infect people the way it does in the show, how supplement cordyceps differs, and what the research says about benefits and safety.
What you'll learn
- What cordyceps is and how it lives in nature
- The "zombie-ant fungus" and whether cordyceps can infect humans
- What cordyceps supplements are and what research shows
- Side effects, drug interactions and who should avoid it
What is cordyceps?
Cordyceps refers to fungi that parasitize insects. The species used in traditional Chinese medicine, now called Ophiocordyceps sinensis (renamed from Cordyceps sinensis in 2007), grows on the larvae of a moth in cold climates. It is also known as Chinese caterpillar fungus, dong chong xia cao and yarsha gumba (Memorial Sloan Kettering). In traditional Chinese medicine it has been used for fatigue and coughs and as a tonic (Memorial Sloan Kettering).
The "zombie-ant fungus"
A related fungus, Ophiocordyceps unilateralis, infects carpenter ants. Infected ants climb to a high spot, bite onto vegetation and stay locked there even after they die. Surprisingly, the fungus extensively colonizes the ant's jaw muscles but not its brain (Mangold et al., 2019). This real-life behavior is what made cordyceps famous as the zombie fungus in The Last of Us.
Can cordyceps infect humans?
No, not in the way the show imagines. Cordyceps species are adapted to infect insects, and body temperature is a major barrier for fungi in general. An analysis of 4,802 fungal strains found that most cannot grow at mammalian body temperatures, and every 1 degree Celsius increase between 30 and 40 degrees ruled out about another 6% of them (Robert & Casadevall, 2009). Warm-blooded animals' steady body heat is a strong defense against most fungi (Robert & Casadevall, 2009). The cordyceps in supplements is not an infection risk; the questions that matter are about side effects and interactions, covered below.
Cordyceps supplements: what is in them
Cordyceps supplements come as capsules, powders and liquid extracts (Memorial Sloan Kettering). Products are made from different sources, including Ophiocordyceps sinensis material, a tablet product called CordyMax Cs-4 used in one exercise trial (Parcell et al., 2004), and the related species Cordyceps militaris, used in a mushroom blend in another (Hirsch et al., 2017). Because these differ, results from one product may not apply to another. Check the label for the species and form.
Cordyceps benefits: what the research shows
| Claim | What studies found | How strong is the evidence? |
|---|---|---|
| Energy and exercise performance | In 22 trained cyclists, 3 g a day of CordyMax Cs-4 for 5 weeks did not improve aerobic capacity or time-trial performance (Parcell et al., 2004). In another trial, a mushroom blend with Cordyceps militaris showed no effect after 1 week, but VO2max improved after 3 weeks in the 10 people who continued (Hirsch et al., 2017). | Mixed; studies in healthy people disagree (Memorial Sloan Kettering). |
| Immune system | Laboratory studies show effects on immune cells (Memorial Sloan Kettering). | Mostly lab and animal work. |
| Hormones | Cordyceps stimulated testosterone production in mice; whether this happens in people is not known (Memorial Sloan Kettering). | Animal data only. |
| Kidney health | Some clinical studies reported benefits in specific patient groups, but analyses found the evidence insufficient (Memorial Sloan Kettering). | Insufficient; not a reason to self-treat. |
In short, cordyceps has a long traditional history and plenty of lab research, but human evidence for its popular uses, such as stamina, is limited and mixed. For how cordyceps compares with other mushroom coffee ingredients, see proven, promising, or marketing?
Cordyceps side effects and dangers
No major side effects have been reported (Memorial Sloan Kettering). The main concerns are interactions (Memorial Sloan Kettering):
| If you take | Possible concern |
|---|---|
| Insulin or other blood-sugar-lowering medicines | Cordyceps may also lower blood sugar, adding to the effect |
| Blood thinners or antiplatelet drugs (such as warfarin) | Cordyceps may increase bleeding risk; there is a case report of excessive bleeding after a tooth extraction |
Memorial Sloan Kettering also advises that people with myelogenous blood cancers should not use cordyceps, based on animal findings on red blood cell production (Memorial Sloan Kettering). Talk with your provider before using it if you are pregnant or breastfeeding, have surgery coming up or take medication.
Cordyceps in mushroom coffee
Cordyceps is a common ingredient in mushroom coffee and matcha blends, usually alongside lion's mane, reishi or chaga. For an overview of those blends and their ingredients, see mushroom coffee: benefits, ingredients and research, and for related mushrooms, see reishi mushroom benefits and side effects and turkey tail mushroom benefits.
Common myths (quick reality check)
Myth: Cordyceps could turn people into zombies like in The Last of Us. Reality: Cordyceps is adapted to insects, and most fungi cannot grow at human body temperature. The show is fiction.
Myth: The zombie-ant fungus controls the ant's brain. Reality: Research found the fungus extensively colonizes the ant's jaw muscles but not its brain.
Myth: Cordyceps is proven to boost stamina. Reality: Exercise studies are mixed: one found no benefit in trained cyclists, another found improvements only after 3 weeks in a small group.
Frequently asked questions (FAQ)
What is cordyceps?
A group of fungi that grow on insects. The species used in traditional Chinese medicine, Ophiocordyceps sinensis, grows on moth caterpillars.
Can cordyceps infect humans?
No. Cordyceps is adapted to insects, and most fungi cannot grow at the temperature of the human body.
Is the Last of Us fungus real?
It is based on a real fungus, Ophiocordyceps unilateralis, which infects carpenter ants. It does not infect people.
What are the benefits of cordyceps?
It is used for energy and stamina, but human studies are mixed. Most research on immune and other effects is in labs and animals.
Is cordyceps dangerous?
No major side effects have been reported, but it may lower blood sugar and increase bleeding risk with blood thinners. Check with your provider if you take medication.
Is cordyceps in mushroom coffee the same as the wild fungus?
Not always. Products use different species and forms, such as Ophiocordyceps sinensis or Cordyceps militaris, so check the label.
Related guides
- Reishi mushroom benefits and side effects
- Turkey tail mushroom benefits
- Grading the evidence behind mushroom coffee
- What are adaptogens?
- Mushroom coffee side effects
Disclaimer and when to seek help
This article is for general education and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your health care provider before using cordyceps, especially if you take insulin, other blood-sugar-lowering medicines or blood thinners, have a blood cancer, are pregnant or breastfeeding, or are having surgery.
References
- Memorial Sloan Kettering Cancer Center. "Cordyceps" About Herbs, Botanicals and Other Products. Last updated February 10, 2022.
- Mangold CA, et al. "Zombie ant death grip due to hypercontracted mandibular muscles." Journal of Experimental Biology, 2019;222(Pt 14):jeb200683. doi:10.1242/jeb.200683
- Robert VA, Casadevall A. "Vertebrate endothermy restricts most fungi as potential pathogens." Journal of Infectious Diseases, 2009;200(10):1623-1626. doi:10.1086/644642
- Parcell AC, et al. "Cordyceps Sinensis (CordyMax Cs-4) supplementation does not improve endurance exercise performance." International Journal of Sport Nutrition and Exercise Metabolism, 2004;14(2):236-242. doi:10.1123/ijsnem.14.2.236
- Hirsch KR, et al. "Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation." Journal of Dietary Supplements, 2017;14(1):42-53. doi:10.1080/19390211.2016.1203386
