Cordyceps
Best evidence: Human trials, weak or mixed
Cordyceps militaris, Ophiocordyceps sinensis
Nothing here is medical advice and nothing here treats or prevents any disease. The grade on each claim describes the strength of the published evidence, not how well the mushroom works. The strongest grade on this page means: trials exist and disagree, or are too small and too poorly designed to conclude anything from.
What is actually being talked about
Cordycepin and adenosine analogues.
Claim by claim
Exercise performance and oxygen uptake
Human trials, weak or mixed
Small trials, several of them in older adults, showing modest improvements in oxygen uptake measures. Trials in trained athletes have generally been less impressive, and most studies used a specific commercial preparation rather than the species in general.
Fatigue
Human trials, weak or mixed
A little supportive evidence, all of it small.
The honest summary
The most consistently over-claimed of the group. The effects seen are real but small and mostly in unfit or older participants, which is a very different claim from the performance marketing built on top of them.
Who should be careful
May affect blood sugar and bleeding. Caution alongside diabetes medication and anticoagulants.
What is actually in the jar
The species question here is not pedantry, it is the whole purchase. The traditional material is Ophiocordyceps sinensis, harvested wild from caterpillars in the Himalaya, and it is one of the most expensive biological products on earth. Almost everything sold as cordyceps is cultivated Cordyceps militaris, or a mycelium-on-grain product. Those are three different things at three wildly different prices, and a cheap jar labelled cordyceps is never the first.
Some links here are Amazon affiliate links. If you buy through one we earn a commission at no extra cost to you, and it never changes what we recommend. Prices were read from Amazon when this page was built and will have moved since.
The others, graded the same way
Several of these interact with real medication. Reishi and cordyceps affect bleeding and blood sugar, chaga is high enough in oxalates to have caused kidney damage in heavy users, and anyone in cancer treatment should raise turkey tail with their oncology team rather than adding it independently. Tell your doctor what you are taking.