Reishi Benefits: What the Studies Show and How to Take It

What is reishi

A mushroom as hard as wood, and very bitter.

Reishi is nothing like a cooking mushroom. It is a polypore: it grows on wood, often at the base of weakened broadleaf trees, and forms a fan-shaped cap, glossy as if varnished, in a deep reddish brown. Its flesh is hard, almost woody, and very bitter. It is not eaten: it is boiled for a long time, or its compounds are extracted.

The Chinese call it lingzhi, the Japanese reishi. In English, it is sometimes called the varnished conk. Ancient Chinese medical texts rank it among the top-tier remedies, and tradition credits it with a long list of virtues. It is this reputation, far more than the studies, that explains its current popularity.

A useful botanical point: a 2012 study showed that most of the “lingzhi” grown and sold in China actually belongs to a closely related species, Ganoderma lingzhi, and not to the European Ganoderma lucidum. The two are very similar, but it is a reminder that a reishi product depends a great deal on the strain and the extraction. To place reishi among the other species, our list of 12 medicinal mushrooms worth knowing covers them all.

The molecules

Two families of molecules, two different promises.

When people talk about reishi benefits, they are really talking about two large families of compounds. They are not extracted in the same way, are not found in the same proportions from one product to another, and are not studied for the same uses.

This has a practical consequence: a water extract, rich in polysaccharides, and an alcohol extract, rich in triterpenes, are not the same product. A reishi powder that is simply ground contains both, but in low concentration, and part of it remains poorly accessible because the mushroom's cell wall is very hard. That is why serious manufacturers state the type of extract and its standardisation. We publish the lab tests of our raw materials on our lab analyses page.

The level of evidence

Reishi benefits, use by use.

Reishi has been the subject of hundreds of studies, but the vast majority were carried out on cells or animals. In humans, trials are few, often small, and sometimes of poor methodological quality. Here is where the research stands for each use.

Summary based on the Cochrane reviews by Klupp (2015) and Jin (2016) and the trials cited below. Full references are at the bottom of the page.

This table does not mean that reishi is useless. It means that, today, no demonstrated effect in humans can be attributed to it. That is also why no health claim is authorised in Europe for this mushroom. So we talk about uses and routines, not promises.

Reishi and sleep

Reishi and sleep: a traditional use, few trials.

This is the question we are asked most. In traditional Chinese medicine, lingzhi is associated with calming the mind, and it is often taken in the evening. Modern research has looked into it, but mainly in animals.

In 2012, a Chinese team showed that a reishi extract prolonged sleep time in rats, with a supposed action on inflammatory messengers involved in regulating sleep. That is interesting, but a rat is not a human, and the doses cannot be transposed. In humans, the most frequently cited trial was not about sleep but about fatigue (see below).

• What we know: in animals, some extracts lengthen sleep.
• What we do not know: whether reishi alone improves falling asleep or the quality of the night in humans. No large controlled trial has shown it.
• What people do in practice: many include it in an evening routine, with other, better-documented ingredients.
• The only ingredient in an evening formula with an authorised claim is melatonin: it contributes to the reduction of time taken to fall asleep.

That is the logic behind Sleep+: reishi sits alongside valerian, magnesium bisglycinate and melatonin, in a capsule taken 30 minutes before bed. To compare reishi with other evening mushrooms, read our comparison of the best mushroom for sleep, and our article on valerian or melatonin for the two most studied ingredients.

Reishi and cortisol

Does reishi lower cortisol? Nobody has measured it.

You read everywhere that reishi “regulates cortisol”. We looked: we found no controlled human trial that measured cortisol before and after taking reishi. The claim rests on traditional use, animal studies and a confusion with ashwagandha, which has been studied on this point.

That does not mean reishi has no place in a routine designed for stressful periods. It means no effect on this hormone can be attributed to it. If this is your concern, the levers with evidence lie elsewhere: sleep, physical activity, managing caffeine, social connection. Our guide on how to lower cortisol ranks them by level of evidence.

Ashwagandha and reishi are often combined, as in Anti-Stress. To understand what sets them apart, see our reishi or ashwagandha comparison.

Reishi and immunity

Immunity: why we remain cautious.

Reishi's beta-glucans are recognised by certain cells of the immune system. In the laboratory, they change their activity. That is where reishi's reputation for natural defences comes from. But going from a cell in culture to an effect on a person's health is a long road, and that road has not been travelled.

The 2016 Cochrane review is often cited as proof. In reality it says something else: in cancer patients already being treated, a few immune markers changed favourably in trials judged to be of low quality. Nothing can be drawn from this for a healthy person who wants to “boost their defences” before winter. And anyone who is ill should talk to their doctor about any supplement before taking it.

Reishi goes into our Immunity formula, alongside chaga and oyster mushroom, as part of a winter routine. Our guide to preparing your immune defences before winter puts these mushrooms in their rightful place, behind the habits that matter most.

Extract, powder, coffee

Reishi powder or extract: the form changes everything.

Reishi is sold in very different forms. The price per gram tells you nothing about the amount of compounds you actually get. Here is how to find your way.

Ganoderma coffees, very widespread in Eastern Europe, are a separate case: we have detailed the composition of one of the best known in our article on DXN Lingzhi Coffee.

For daily use, a standardised extract in a capsule remains the simplest form: the dose is fixed, the bitterness disappears, and the standardisation tells you what you are taking. You will find our reishi ingredients on our reishi page.

What dose

How much reishi should you take per day?

There is no official dose. Trials have used very different amounts: 1.44 g of extract a day in the Wachtel-Galor study, 5.4 g of polysaccharide extract in the Tang study. Commercial supplements most often offer around 1 to 1.5 g of extract a day. The right dose is the one stated on the label of the product you choose, because it depends on the concentration of the extract.

Our mushroom coffee, Brainstoorm, does not contain reishi: it combines Lion's Mane, Cordyceps and Chaga. If you are looking for daily reishi, it is our capsules that contain it. The amounts per capsule are on the label of each product.

How to take it

How to take reishi, morning or evening.

Tradition favours the evening, and that is also when most people take it. But the timing mainly depends on the formula: reishi combined with melatonin is taken at bedtime, while reishi combined with ashwagandha can be taken in the morning.

Do not expect an overnight effect, or a spectacular one. Reishi is neither a sleeping pill nor a sedative. If you notice nothing after a month, that is useful information, not a failure.

Precautions

Reishi: who should avoid it?

In short trials, reishi is generally well tolerated. The adverse effects reported are mainly digestive: discomfort, loose stools, dry mouth, sometimes skin rashes. But a few cases of serious liver damage have been published with reishi powders, and the mushroom could enhance the effect of certain medicines. We will devote a full article to its side effects.

Always stick to the dose stated on the label and do not combine several reishi products. For the broader question of medicinal mushroom safety, our article on the risks of mushrooms and adaptogenic plants sets out the facts.

Sources

1. Tang W., Gao Y., Chen G. et al. (2005). A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. Journal of Medicinal Food, 8(1).
2. Wachtel-Galor S., Tomlinson B., Benzie I. F. F. (2004). Ganoderma lucidum ("Lingzhi"), a Chinese medicinal mushroom: biomarker responses in a controlled human supplementation study. British Journal of Nutrition, 91(2).
3. Klupp N. L., Chang D., Hawke F. et al. (2015). Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database of Systematic Reviews, CD007259.
4. Jin X., Ruiz Beguerie J., Sze D. M., Chan G. C. (2016). Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database of Systematic Reviews, CD007731.
5. Wachtel-Galor S., Yuen J., Buswell J. A., Benzie I. F. F. (2011). Ganoderma lucidum (Lingzhi or Reishi): a medicinal mushroom. In Herbal Medicine: Biomolecular and Clinical Aspects, 2nd ed., chapter 9. CRC Press.
6. Cao Y., Wu S. H., Dai Y. C. (2012). Species clarification of the prize medicinal Ganoderma mushroom "Lingzhi". Fungal Diversity, 56.
7. Cui X. Y., Cui S. Y., Zhang J. et al. (2012). Extract of Ganoderma lucidum prolongs sleep time in rats. Journal of Ethnopharmacology, 139(3).
8. Wanmuang H., Leopairut J., Kositchaiwat C. et al. (2007). Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. Journal of the Medical Association of Thailand, 90(1).

Keep reading

Further reading.

Reishi is only one of the medicinal mushrooms. Explore our other guides, or our reishi page.