Welcome to the first in what I envision as a series of blog posts, introducing the best of the medicinal mushroom world! Let us kick off with a particularly weird and wonderful fungus with a long and illustrious history of medicinal use, that technically is not even a mushroom: Cordyceps!
Cordyceps are particularly fun fungi! Fungal species feed on their preferred type of organic matter, typically dead/decaying plant matter. Most species of cordyceps however, uniquely parasitise insects and other arthropods (entomopathogenic fungi). This results in what can be an alarming visual, as the mycelium infiltrates and digests the insect before the fruiting body (an ascocarp rather than a mushroom) pops out of the digested corpse! This may make our delicate hearts faint or our stomachs churn, but this is our natural world and if we can embrace it, we reap wonderful rewards!
Cordyceps is not a totally clear term, as it can refer to the general collection of fungus found in the Cordyceps and Ophiocordyceps genera, or specific species within these groups.
The original Cordyceps (previously identified as C. sinensis, now O. sinensis) is a rare species, native to the Tibetan plateau region. Its fruiting body has been revered in traditional medicine systems from across Asia with the earliest written account of its use dating to 1757, Qing Dynasty, China . The Chinese name for this species (dōng chóng xià cǎo) translates to “summer grass winter worm”, or it is known in English as the caterpillar fungus, referring to its host.
Traditional uses for Cordyceps fruiting body in Asia include: [1,2]
Whole body tonic (invigorant)
Energy enhancer, to boost stamina
Convalescence after infection and severe illness
Invigorating the lungs, respiratory diseases,
Kidney, heart and stomach disorders, (and more)
Unfortunately, Ophiocordyceps sinensis is rare in nature, costs a fortune, and the fruiting body cannot be cultivated! Therefore, to access the health benefits of Cordyceps we are faced with two choices: use the (non-traditional) mycelium of O. sinensis or find a medically interchangeable species with a cultivatable fruiting body. For the mycophobic it may be reassuring to note that commercial Cordyceps is grown on substrates free from insects!
Happily, other species of Cordyceps have a history of medicinal application, notably C. militaris (Trooping Cordyceps). Used in China as a tonic for hundreds of years now, this bright orange-red fruiting body is not only far more abundant in nature but is also easily cultivatable, so affordable . We now have a body of research that indicates these two species offer similar physiological effects . In fact, recent profiling found the two species share 83% of pooled primary metabolites . As such, my preference currently is to use C. militaris fruiting body for the best results.
There are diverse medicinal applications for Cordyceps, which appears to offer some unifying, harmonising quality, likely related to its general tissue protecting, metabolic regulating and organ tonifying effects.
C. militaris has two key types of bioactive constituent worth noting. Firstly, and as with all medicinal mushrooms, there are many unique polysaccharides. Polysaccharides are long indigestible polymers of sugar molecules which are commonly found in nature, think seaweed, grains, yeast, herbs. The polysaccharides from mushrooms play an especially important role in communicating with and improving immune system function. The specific polysaccharides give the various medicinal mushrooms their unique clinical focus. In the case of Cordyceps, it is a unique focus on lung, kidney, heart health and convalescence.
Secondly and uniquely, there is an abundance of nucleosides. Nucleosides are the structural subunits of our DNA and RNA, and C. militaris offers some of these including uridine, adenosine, and the major bioactive compound, cordycepin (A.K.A. 3’deoxyadenosine) . The explanation is complicated, but in a nutshell cordycepin mimics our endogenous adenosine which has implications for energy metabolism and a whole host of other metabolic functions. This mechanism likely underpins many of the benefits C. militaris has to offer .
Cordyceps is revered in folk traditions for improving physical stamina. This is illustrated by a study that saw a significant improvement in oxygen utilisation and extension of the time taken to reach exhaustion with high-intensity exercise, after only 3 weeks use . The participants took C. militaris in a mixture with other medicinal mushrooms for this effect, which is frustrating because we cannot be sure it was the Cordyceps that was key to this activity. An older study reveals O. sinensis (1 g daily) improves exercise performance in healthy 50-75 year-olds . Others investigated it combined with Rhodiola crenulata, a powerful adaptogen likely to have synergistic effects with Cordyceps, and they indicate improved aerobic performance  and body composition  effects.
Human evidence shows that 100 mg of C. militaris fruiting body extract is effective to protect organ function in cases of advanced kidney disease (a double-blind, placebo-controlled, randomized clinical trial of 98 subjects). Here, Cordyceps protects against disease progression, with significantly improved markers of kidney function and health, attributed primarily to the cordycepin content .
More human trials have come out of Asia investigating O. sinensis for use in kidney transplants as an adjuvant to standard immunosuppressive therapy. Here we have an opportunity to see the protective activity supporting the delicate kidney tissue working in combination with the complex immune modulating capacity largely derived from the fungal polysaccharides – two key strengths of Cordyceps. While there is yet much study to do, meta-analyses outline a number of benefits in these cases [11,12]. We are talking about not only improved graft acceptance and healing rates, but also reduced side effects of immunosuppressant drugs, as well as better performance from kidneys and liver.
Two human trials particularly illustrate the immune-enhancing capacity of C. militaris (both randomized, double-blind and placebo-controlled). The first found that 1.5 g of fruiting body (ethanol extract with 1.9 mg/g cordycepin) enhances cell-mediated immune function in a healthy population, with significant increases in NK cell activity and in lymphocyte proliferation after 4 weeks of use . Recently, a Korean study looked at a population of one hundred adults with a history of at least two colds contracted per year, and found 12 weeks of C. militaris significantly improved immune response (evidenced by raised natural killer cell activity and IgA levels compared to placebo) . O. sinensis has demonstrated similar results, enhancing cell-mediated immunity and reducing inflammatory response .
Safety, Quality and Dosing
When purchasing a Cordyceps product, it is important to consider a few key points to ensure you are getting the quality required for results. I will outline these briefly:
Positively identify the contents as C. militaris for the most effective medicinal species, able to be grown commercially (no over-harvesting of O. sinensis). There are other species with potential value however research is limited for these thus far.
Seek a fruiting body rather than mycelium extract (or at least both parts together if fruiting body alone cannot be sourced). One of the reasons for this is that only the fruiting body contains high levels of cordycepin .
If the product claims standardised levels of cordycepic acid, do not be tricked! Cordycepic acid is not the same as cordycepin, and it turns out it is not a particularly remarkable compound at all, being otherwise known as mannitol, a sugar which is found in all mushrooms! 
I recommend the equivalent of 2-5 g of C. militaris dry fruiting body daily. Higher doses are recommended in cases of cancer or other extreme conditions. Cordyceps is best taken in a divided dose due to the fast half-life (bodily elimination) of that magical compound cordycepin; divide your daily dose into 2-4 doses to be taken throughout the day for best results.
Cordyceps is generally considered to be safe for consumption when used in the above dosage range, with only occasional reports of mild gastrointestinal side effects, including nausea, diarrhoea and dry mouth.  If you are one of the unlucky few to experience such side effects, try lowering the dose or having with food.
I recommend Cordyceps particularly to people with a need for lung support, kidney support, convalescence after infection or illness, improved vitality and as part of a general daily health prophylaxis regime, including healthy aging when taken long term…
If you would like a more in-depth and clinically-focused take on this amazing mushroom, see my Cordyceps Monograph [COMING SOON!].
 Olatunji OJ, Tang J, Tola A, et al. The genus Cordyceps: An extensive review of its traditional uses, phytochemistry and pharmacology. Fitoterapia. 2018 Sep;129:293-316.
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