Medicinal mushroom series, part 1
Cordyceps is everywhere right now: in pre-workouts, mushroom coffees and adaptogen blends, usually promising more oxygen, stamina and energy. Clients ask me about it all the time, especially runners and padel players looking for an edge.
So what are the real cordyceps benefits, and what’s just marketing? Here’s what the research shows, how to take it, who should avoid it, and how to pick a product worth your money.
Before we get to the science, here’s why cordyceps has such a dramatic reputation. In the wild, these fungi infect insects and grow out of their bodies, as David Attenborough shows in this short clip from the BBC’s Planet Earth:
Don’t worry: the cordyceps in supplements has nothing to do with insects. Quality products today are grown in labs on plant-based media.
What is cordyceps?
There are two main types you’ll see on labels:
Cordyceps sinensis (often sold as CS-4): the original wild mushroom is rare and very expensive, so supplements use a lab-grown strain called CS-4. This is what most of the human research used.
Cordyceps militaris: a different, easily cultivated species. It’s common worldwide, but in the EU it isn’t authorised for use in food supplements.
What this means for you: if you live in Spain or elsewhere in the EU, look for Cordyceps sinensis or CS-4 on the label.
Does cordyceps improve oxygen uptake and endurance?
This is the big claim, so let’s be honest about it. VO2 max is how much oxygen your body can use during hard exercise, and it’s a key marker of fitness.
What research suggests:
In healthy adults aged 50 to 75, 12 weeks of CS-4 improved how hard they could work before getting out of breath. Their VO2 max itself didn’t change much.
In young, recreationally active adults, a mushroom blend containing cordyceps improved VO2 max after three weeks, but only in a very small group.
A 2025 review of studies in athletes found small improvements in endurance and oxygen use.
But: in trained cyclists, five weeks of cordyceps made no difference at all. And all of these studies are small.
My take: cordyceps may give a modest boost, mainly if you’re older or less trained, and only after several weeks of daily use. It’s an optional extra, not a game changer. If performance is your goal, start with the supplements that have much stronger evidence, like those in The 5 Sports Supplements That Actually Deserve Your Money, especially creatine.
Other potential benefits
Energy: many people report steadier energy. It’s not a stimulant, so effects are subtle. If you’re always tired, check the basics first (iron, B12, vitamin D, sleep).
Immune support, blood sugar, libido and testosterone: mostly lab and animal research so far. Interesting, but not proven in humans.
How much should you take?
Most studies used 1 to 3 g a day of CS-4. Concentrated extracts need less, so follow the label. Give it at least 3 to 4 weeks: in the research, nothing much happened in the first week or two.
Mario's tip
Take cordyceps in the morning or before training, and give it 3 to 4 weeks before you judge it. Jot down how your usual sessions feel (effort, breathing, recovery) so you're comparing like with like.
Who should be careful?
Cordyceps is generally well tolerated, with occasional mild tummy upset. Speak to your doctor first if you:
take blood thinners or have surgery coming up
take diabetes medication
have an autoimmune condition or take immunosuppressants
are pregnant or breastfeeding
Competing athletes should choose batch-tested products, as blends can be contaminated.
How to choose a good product
Species: Cordyceps sinensis or CS-4 (essential in the EU).
Extract, not filler: many cheap products are mostly ground-up grain. Look for a proper extract.
Tested quality: batch analysis or third-party testing for purity and contaminants.
Honest claims: cordyceps has no approved health claims in the EU. If a product promises to “reduce tiredness”, that claim belongs to an added vitamin like B12 or C, not the mushroom.
My pick: Hifas da Terra Mico-Cord, made in Galicia from the CS-4 strain used in the research. It’s available from Amrita Nutrition with my 10% lifetime discount. In the UK, try Natural Dispensary, also with 10% off.
How I can help
Supplements work best as the last piece of the puzzle. With my clients, we start with what moves the needle most: fuelling, key nutrients, sleep and recovery. Then we decide together whether something like cordyceps is worth adding and safe with your medication.
Not sure if cordyceps suits you? Book a free 15-minute call or have a look at my sports nutrition support for runners and padel players.
Coming next
Next in the series: lion’s mane, reishi, turkey tail and chaga. Same approach: what the research shows, and what’s just marketing.
FAQ
Does cordyceps increase VO2 max?
Possibly, but only modestly. Some small studies found improvements in oxygen use and endurance, mainly in older or less-trained people after several weeks. A study in trained cyclists found no effect.
How long does cordyceps take to work?
In the research, little happened in the first one to two weeks. Effects appeared after about three weeks of daily use, so give it at least 3 to 4 weeks.
What is the difference between Cordyceps sinensis and Cordyceps militaris?
They are different species. Most supplement research used CS-4, a lab-grown strain sold as Cordyceps sinensis. Cordyceps militaris is widely cultivated but is not authorised in EU food supplements.
What are the side effects of cordyceps?
It is usually well tolerated, with occasional mild digestive upset. Check with your doctor first if you take blood thinners, diabetes medication or immunosuppressants, have an autoimmune condition, or are pregnant or breastfeeding.
What is the right cordyceps dosage?
Most studies used 1 to 3 g per day of CS-4. Concentrated extracts are taken at lower doses, so follow the product label.
View scientific references
Chen S, Li Z, Krochmal R, Abrazado M, Kim W, Cooper CB. Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: A double-blind, placebo-controlled trial . Journal of Alternative and Complementary Medicine. 2010;16(5):585–590.
Hirsch KR, Smith-Ryan AE, Roelofs EJ, Trexler ET, Mock MG. Cordyceps militaris improves tolerance to high-intensity exercise after acute and chronic supplementation . Journal of Dietary Supplements. 2017;14(1):42–53.
Jędrejko M, Jędrejko K, Granda D, Kała K, Pokrywka A, Muszyńska B. Current evidence of ergogenic and post-exercise recovery effects of dietary supplementation with Cordyceps militaris in humans: A narrative review . Nutrients. 2026;18(5):781.
Parcell AC, Smith JM, Schulthies SS, Myrer JW, Fellingham G. 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.
Shu MY, Zhang XC, Zuo L, Jiang FL, Liang J, Li F. Effects of fungal supplementation on endurance, immune function, and hematological profiles in adult athletes: A systematic review and meta-analysis . Frontiers in Nutrition. 2025;12:1670416.
