What Does Science Say About the Health Benefits of Cordyceps?

Cordyceps are technically not mushrooms. They're a type of parasitic fungus. More than 400 species grow in different parts of the world, commonly Asia, but also in Bolivia, Peru and the United States. These fungi tend to thrive in tropical rain forests.

But the type reportedly consumed by Wang during her training and credited for giving her an athletic edge is from a species once known as Cordyceps sinensis, now scientifically known as Ophicordyceps sinensis or O. sinensis. This species is found naturally in China, Nepal, Tibet and India.

O. sinensis are entomopathicgenic fungus, meaning it grows on insects. This species, in particular, grows on the caterpillar of the Thitarodes ghost moth, which live in elevations above 10,000 feet (3,048 meters). The fungal spores attach to the caterpillar and slowly consume its body. As the larvae begins to die, it burrows into the ground. As the fungus grows, it sends a small beige-orange shoot, or fruiting body, up through the soil. These are harvested beginning in late May with pickaxes to gently upturn clumps of dirt. O. sinensis bring in big bucks, but ones with the caterpillar still attached fetch far more money than those without.

These unusual fungi have acquired several nicknames, too. The Tibetans call it "yartsa gunbu," meaning "summer grass, winter worm," which describes when the larva and fungus remain intact. The Nepalese call it the keera jhar, or insect herb. Because the fungus must consume its host to grow, it's also referred to as "caterpillar fungus" and more casually, "zombie fungus."

What drew locals to even sample cordyceps in the first place were yaks. Centuries ago, herders in Nepal would take their yaks to higher elevations to graze in the fresh spring grasses. Afterward, the herdsmen noticed the animals were more active and aggressive during rutting.

Curious what might be causing such vigor in their cattle, the herdsmen took closer notice of what the yaks were eating and discovered among the grass the fruiting body of the O. sinensis rising up through the blades. Adventurous herdsmen apparently thought, what's good for the goose is good for the gander, and consumed it themselves. Finding it quite satisfactory, the fungus was then gathered for its aphrodisiac qualities.

The first known reference of its medicinal uses date back to a 15th-century Tibetan text, which credits O. sinensis as being "the most marvelous of all pleasures." It was first used in traditional Chinese medicine to increase longevity and cure erectile dysfunction, and has grown among traditional healers to treat as many as 21 different ailments, from cancer and tuberculosis to colds and jaundice.

Cordyceps contain the active ingredient cordycepin, which has been shown to have anti-inflammatory and anticancer effects. The fungus is believed to enhance oxygen utilization and increase blood flow, which may improve athletic performance and is considered the secret to Wang's success.

Wang's showing at the National Games did a lot to raise awareness of the fungus. But in 2003, during the severe acute respiratory syndrome (SARS) outbreak, O. sinensis was touted as a cure, and sales exploded, as did the price. Today they can cost as much as $20,000 a kilogram, according Realmushrooms.com, making it the most expensive fungus in the world.

A quick Google search unearths dozens of "Cordyceps supplements" in the form of tinctures, powders, pills and teas. These may contain cordycepin, the same active ingredient in O. sinensis, but they are most likely not made with wild O. sinensis fungi. This is primarily because O. sinensis demands such a high price.

When demand skyrocketed in the 1980s, scientists and supplement manufacturers in China found ways to cultivate cordyceps anamorphs, essentially mycelium (where cordycepin is found) that do not produce fruiting bodies. These anamorphs, known as cordyceps Cs-4, have been found to be similar to O. sinensis grown in the wild.

"On one level, these are different organisms, not even in the same family, but they share some of the active ingredients," ethno-mycologist Daniel Winkler, who runs Mushroaming.com, says via email. In 2007, Cordyceps sinensis and several other cordyceps were moved from the genus Cordyceps to the genus Ophiocordyceps. "If you buy Ophiocordyceps sinensis in a supplement store in the West, these products do not contain O. sinensis but Paecilomyces sinensis, a related fungus living within the wild Ophiocordyceps sinensis."

"Most medical research has been carried out using this fungus known as Cs-4 (cordyceps sinensis strain No. 4)," with promising results, Winkler says. "But recently DNA analyses revealed this strain not to be identical to Ophiocordyceps sinensis."

In the United States, some manufacturers have developed ways to grow cordyceps on grain, referred to as cordyceps militaris. From this they create cordyceps mushroom extracts that are promoted for similar health benefits as O. sinensis.

The species cordyceps militaris has been found to have anti-fatigue effects in mice. Other studies — also only on mice — found that extracts of cordyceps sinesis and cordyceps militaris improved brain function and boosted antioxidative enzyme activity, which could fight cell damage that comes with aging. Cordyceps sinesis also improved the sexual function of castrated rats. More studies need to be performed to know whether the same results would be replicated in humans.

Other studies have shown it difficult to determine how much mycelium or cordycepin is actually in cordyceps militaris. Some supplements that contain cordyceps militaris tout the benefits of their products by using cordyceps Cs-4 research, which is misleading.

And limited government oversight of supplements further muddies the water, making it difficult for consumers to know whether the products they buy actually contain the active ingredient or dosage listed on the label. In short, you should research to determine if a supplement is authentic and trustworthy.

It is also important to note that while Wang Junxia's 1993 athletic performance may have been aided by her use of caterpillar fungus, there may have been other factors in play. In 2016, she admitted that during her best running season when she broke the world record, she was involved in a Chinese state-sponsored doping regime.