Cordyceps. You’ve probably heard of them in one of two ways. One, if you’ve watched The Last of Us and recall a post-apocalyptic world that is ravaged by a deadly fungal infection caused by a mutated strain of… cordyceps. Secondly, if you are into your supplements and have seen brands such as Puresport, The Herbtender, or Dirtea launching new ranges of supplements that are said to improve cardiovascular performance and endurance through the use of cordyceps.
Fortunately, cordyceps aren’t about to trigger the apocalypse – at least, not in humans. But for caterpillars, the story is far less comforting.
“It grows in the wild on caterpillars, so it is a parasite. It’s happy for a while, and then it just takes over the whole caterpillar. The caterpillar then dies, and the mushrooms grow out of the top of the caterpillar's head. It produces spores and then goes on to infect other caterpillars,” explains Schia Mitchell Sinclair, medicinal herbalist, craniosacral therapist, and chief herbalist for The Herbtender.
“In the original form, it would have been gathered and then cooked – the whole lot, caterpillars and mushrooms – and then used in a tea, or I actually read that one Chinese Emperor made a cordyceps stuffing and put it in meat.”
While its origins are more suited to a horror film than a health supplement, cordyceps have long been revered in traditional Chinese medicine for their potential to boost vitality and endurance. Today, those same properties have captured the attention of athletes and scientists, with research exploring this mushroom’s impact on performance.
Studies have shown promising results, too. Research by the Royal Society of Chemistry found that long-distance runners experienced improved endurance. A study published in the Journal of Exercise Physiology highlighted significant increases in metabolic and ventilatory thresholds. Another study from the National Library of Medicine found that endurance cyclists saw measurable gains in physical performance after three months of supplementation.
Beyond athletic performance, cordyceps have also been explored for their potential benefits in respiratory health. “Cordyceps also came up over Covid,” Sinclair adds. “ Stephen Harrod Buhner, an American herbalist, wrote an awful lot about treating Covid with cordyceps, partly because Covid affected how we use oxygen and cordyceps improve how we use oxygen.”
But before you start picturing a cupboard full of caterpillar-infused supplements, cordyceps today are far from the cordyceps found in an Emperor's stuffing (confirmed by Sinclair, too, in case you were concerned). The strain traditionally harvested from caterpillars is rare, expensive, and difficult to grow at such a large scale, only found on the Qinshai-Tibetan Plateau of China at an altitude of around 10,000 feet. Instead, supplement companies typically use a strain called CS-4.
“This is where they have taken the caterpillar and the mushrooms, and they have fermented it in a batch. So they now have a strain which is so far distant from the original caterpillar and mushroom. They then grow it in a fermentor and dry it – this is what we use now. It is called cordycepensis, and it is a mycelial form of it,” she explains.
In the performance realm, cordyceps first gained attention in 1993 when a group of Chinese female runners achieved records in the 1,500m, 3,000m, and 10,000m races. It was their coach who attributed their success to a diet which included cordyceps and suggested that the supplement improved exercise capacity in these athletes via antioxidant effects. Sinclair echoes this, highlighting that cordyceps are said to increase a person’s ability to utilise oxygen as well as reduce the production of lactic acid, meaning an athlete doesn’t go into anaerobic respiration as quickly.
“It also improves recovery time because we don’t have the same aches and pains,” she says. “In Perform & Recover [The Herbtender’s product featuring cordyceps], we’ve got other herbs such as rhodiola, which also improves the utilisation of oxygen and reduces lactic acid production. People who take cordyceps and rhodiola also have less creatine kinase after, which measures micro tears in the muscles. It was shown that taking these herbs can reduce heart rate in eight weeks and improve aerobic performance in 12 weeks, as well as reduce what they call perception of effort. In other words, you don’t feel like you’ve done as much, which allows you to train harder and for longer.”
The mushroom, which Sinclair says is a strikingly beautiful orange colour in its natural state, is a type of adaptogen – a subgroup of herbs, dubbed the “super herbs”, that are renowned for their ability to manage stress in the body. Cordyceps, like rhodiola, ginseng, and holy basil, belong to the adaptogen family – herbs that help regulate cortisol, support adrenal function, and combat inflammation and oxidative stress, all of which are raised during intense exercise. “These adaptogens can help bring these levels back to normal levels, which, again, keeps you going for longer,” Sinclair says.
The benefits that can be achieved from each herb or adaptogen for performance, such as cordyceps, rhodiola, and ginseng, is why at The Herbtender, for their Perform & Recover supplement, Sinclair uses a blend of herbs, including reishi, cordyceps, rhodiola, red ginseng, white ginseng, and acerola cherry – all of which fall under the category of adaptogen, functional mushroom, micronutrient, functional herb and/or nootropic. “My herbalist training is very much as a polypharmacist, so using a combination of four or five herbs to help that person. Sometimes a combination of herbs is much more powerful than one,” she says.
But she is clear in pointing out that taking supplements is not always beneficial to everyone or that you have to take a certain supplement for the rest of your life. Sinclair recommends taking a cordyceps supplement if you are going through a period of active training, such as training for a cycling event, and while if you took a big dose now, you’d feel the benefits almost immediately, Sinclair recommends that you take a low dose for a longer period to see the long-term impacts on your performance.
While training for a marathon in 2024, Alex Griffiths, a hybrid athlete now preparing for an Ironman 70.3, experimented with cordyceps supplements to see if they could improve his endurance. “I did feel some small benefits, but decided to stop taking them after my marathon,” he says. “I may start using them again for my Ironman 70.3, but one of the main reasons for stopping taking them is the costs – they’re an expensive supplement to buy consistently.”
Pip Mills, an endurance athlete who competes in cross-country running, Hyrox competitions, and cycling events, has incorporated cordyceps into her supplement routine – but remains uncertain about the impact. “I do take them but don’t know how much it works,” she says, adding that she started taking the Puresport cordyceps after a good experience with other products in the brand's range.
“I started taking it towards the end of last year [2024] because I was training for the Royal Parks Half Marathon and I did get a time that I was really quite proud of. I don't know if that was because of the training or if it was because of the benefit of using it. It's hard to know because I've only ever taken them while I have been doing a specific plan,” Mills adds.
This is something Sinclair has observed as well. She explains that for athletes with already high levels of fitness, the benefits of a supplement designed to enhance cardiovascular performance may be less noticeable.
So, while cordyceps might not be the magic bullet for every athlete, the growing body of research and anecdotal evidence suggests they can play a role in enhancing endurance, oxygen efficiency, and recovery. Their effectiveness, however, depends on the individual. Cordyceps may spell the end for caterpillars, but for athletes, they could mark the beginning of better endurance.
