Reishi Mushroom (Ganoderma lucidum), Audited Trial by Trial

Reishi mushroom benefits are narrower than the first page of results suggests. Ganoderma lucidum has been tested in humans mostly in patients rather than in healthy people, and what those trials measured was specific: T cell subsets and Karnofsky quality of life scores in cancer patients already on chemotherapy, fatigue and wellbeing scales in patients diagnosed with neurasthenia, and glucose, lipid and body composition values in people with type 2 diabetes. A 2025 meta-analysis pooling seventeen randomised trials in 971 people rated the certainty of every single pooled outcome as very low.

Ask what is reishi good for, or what is reishi mushroom good for, and most pages answer with cell cultures and mice for effects they describe in people. This page lists the human trials one at a time, with the dose, the duration, the population and the arms that found nothing, then names two Cochrane reviews that concluded against use. It also answers the question the evening-stack buyer is actually asking, which is whether reishi is a sedative. It is not. What an adaptogen is in the first place belongs to our definition page.

How to read a reishi claim before you believe it

Almost every claim about reishi mushrooms benefits fails on one of six points. Every trial below is described against all six, and you can apply them to any label you pick up next.

Which part of the fungus was used. Ganoderma lucidum is sold as a dried fruiting body, as mycelium grown on grain, and as cracked spore powder. These are chemically different materials, and a trial on one says nothing about the others.

How it was extracted. Hot water pulls out the polysaccharides, including the beta-glucans. Ethanol pulls out the triterpenes, the ganoderic and lucidenic acids that give reishi its bitterness. A single-solvent extract gives you one family and largely misses the other, which is why the extraction method decides what is in the capsule.

What was in the material. The Ganoderma lucidum chapter in the NIH Bookshelf reference Herbal Medicine: Biomolecular and Clinical Aspects reports commercial product surveys in which triterpene content ranged from undetectable to 7.8 per cent and polysaccharide content from 1.1 to 5.8 per cent. Undetectable is the word to sit with.

The dose actually given. Across the seventeen trials in the 2025 meta-analysis, daily doses ran from 200 mg to 11,200 mg. That is a fifty-six-fold spread. A result at 3 g of extract has nothing to say about 250 mg of powder.

Who was in the trial. The large majority of reishi participants were patients with cancer, type 2 diabetes or a psychiatric diagnosis, recruited in China, Hong Kong or Australia. Healthy European adults are almost absent from this literature.

What was not measured. In the five randomised cancer trials pooled by Cochrane, not one recorded long-term survival. That absence is more informative than any of the markers that were recorded.

What Ganoderma lucidum actually is

What is reishi? It is the Japanese name for the fungus Ganoderma lucidum. Lingzhi is the Chinese name for the same thing, which is why labels carry ling zhi reishi, lingzhi reishi mushroom and reishi ganoderma lucidum interchangeably. It grows as a hard, kidney-shaped bracket on hardwood, with a lacquered upper surface that looks varnished. It is woody rather than fleshy, so nobody eats it and every product is an extract, a powder or a decoction.

Two chemical families carry the interest. The polysaccharides are large branched sugars, mostly glucose-based beta-glucans, and they are what hot water extraction recovers. The triterpenes are smaller lipid-soluble molecules, and more than one hundred with defined structures have been described from this species, of which around half are unique to it. Ethanol recovers those. A dual extract has been through both steps, which is a technical claim you can ask a seller to evidence.

Form	What it is	What it typically contains	The catch
Dried fruiting body powder	milled bracket, no extraction step	whole material, low concentration of both families	woody chitin is poorly digestible, so much stays locked in
Hot water extract	decoction, concentrated and dried	beta-glucans and other polysaccharides	triterpenes largely absent, so the bitterness is missing
Ethanol or dual extract	solvent step, alone or after water	triterpenes, or both families	more expensive, and rarely quantified on the label
Mycelium grown on grain	fungal threads grown on rice or oats	variable, plus residual grain starch	the grain is weighed in, so the mushroom fraction can be small
Cracked spore powder	milled spores from the mature bracket	lipids and triterpenes	MSKCC notes spore powder may raise the tumour marker CA72-4

If a label states only the milligrams, and not the part, the solvent and the standardisation, it has told you almost nothing. Ask for all three before you compare two jars on price.

What the trials in healthy adults measured

There is one careful randomised trial of reishi in healthy people, and it is the one reishi pages skip. Wachtel-Galor, Tomlinson and Benzie (2004), publishing in the British Journal of Nutrition, ran a double-blind, placebo-controlled crossover study in 18 healthy adults aged 22 to 52. Participants took 1.44 g of a commercial encapsulated Lingzhi preparation daily, stated as equivalent to 13.2 g of fresh mushroom, for four weeks.

They measured antioxidant status, coronary risk markers, DNA damage, immune status, inflammation markers, and liver and kidney panels. No significant change was found in any of the variables. A slight trend toward lower lipids appeared, and antioxidant capacity measured in urine increased. The authors framed the absence of liver, kidney and DNA toxicity as the reassuring finding, and called for controlled intervention trials in people who actually have something to correct.

The same Hong Kong group then did exactly that. Chu and colleagues, in the British Journal of Nutrition in 2011, gave the same 1.44 g daily dose to 23 evaluable adults with borderline elevations of arterial pressure or cholesterol, in a crossover design across two twelve-week periods. BMI, arterial pressure, antioxidant capacity, lymphocyte subsets, urinary catecholamines and the cortisol to cortisone ratio all failed to move. Plasma insulin and HOMA-IR rose less on Lingzhi than on placebo, and that difference was not statistically significant. In the first treatment period only, triacylglycerols fell 8 per cent and HDL cholesterol rose 24 per cent, but a significant carry-over effect meant the second period could not confirm it.

Two trials, one negative and one mostly negative, in the population most people buying reishi actually belong to. That is the honest baseline, and everything below has to be read against it.

The trials in patients, one at a time

Trial	Population	Dose and duration	Measured	Result
Jin et al. 2016, Cochrane review	373 cancer patients across five randomised trials	various, one to three months	tumour response, T cell subsets, NK activity, Karnofsky score	tumour response RR 1.50, CI 0.90 to 2.51, not significant; CD3 up 3.91 per cent, CD4 up 3.05 per cent, CD8 up 2.02 per cent; no trial recorded survival
Tang et al. 2005, Journal of Medicinal Food	132 Chinese patients diagnosed with neurasthenia	1,800 mg polysaccharide extract three times daily, 8 weeks	Clinical Global Impression severity, fatigue and wellbeing visual analogue scales	fatigue score fell 28.3 per cent against 20.1 per cent on placebo; 51.6 per cent rated more than minimally improved against 24.6 per cent
Klupp et al. 2015, Cochrane review	398 participants across five trials, analysable data from three	1.4 g to 3 g daily, 12 to 16 weeks	HbA1c, glucose, lipids, arterial pressure, BMI	no clinically or statistically significant change in HbA1c, total cholesterol, LDL or BMI
Klupp et al. 2016, Scientific Reports	84 adults with type 2 diabetes and metabolic syndrome	3 g daily, 2,240 mg extract plus 740 mg spores, 16 weeks	HbA1c and fasting glucose as primary outcomes	HbA1c difference 0.13 per cent, CI minus 0.35 to 0.60, p 0.60; no change in any secondary outcome
Jafari et al. 2025, Food Science and Nutrition	971 participants across 17 randomised trials	200 mg to 11,200 mg daily, 1 to 24 weeks	twenty health indices	BMI, creatinine, glutathione peroxidase and heart rate changed; certainty rated very low for every outcome

Cancer, and what the Cochrane review actually concluded

This query carries real weight in German, where people type reishi bei krebs, and it deserves a direct answer. Jin, Ruiz Beguerie, Sze and Chan published a Cochrane review in 2016 pooling five randomised trials in 373 cancer patients. Where reishi was added to chemotherapy or radiotherapy, the tumour response rate was higher, at a relative risk of 1.50 with a confidence interval from 0.90 to 2.51, which crosses one and is therefore not a significant result. Used alone, the reviewers described the antitumour effect as negligible. T cell subsets rose by two to four percentage points. Karnofsky performance scores were relatively better.

The reviewers concluded that they did not find sufficient evidence to justify Ganoderma lucidum as a first-line cancer treatment, and that it should be considered only as an adjunct to conventional care. All participants were Chinese, sample sizes were small and randomisation was often unclear. Adverse events were minimal and limited to nausea and insomnia. If you are being treated for cancer, this is a conversation for your oncologist, and the interaction risks are set out below.

Fatigue, and the one trial people quote

Tang and colleagues (2005) is the study behind almost every claim about reishi and energy. It randomised 132 Chinese patients diagnosed with neurasthenia under ICD-10 to a polysaccharide extract, Ganopoly, at 1,800 mg three times a day, or placebo, for eight weeks. In 123 assessable patients the sense-of-fatigue score fell 28.3 per cent from baseline against 20.1 per cent on placebo, and 51.6 per cent of the extract group were rated more than minimally improved against 24.6 per cent on placebo.

Read the design before you read the numbers. That is 5.4 g of one specific branded polysaccharide extract per day, in patients with a diagnosis, on subjective scales, twenty-one years ago, and never replicated. The placebo group also improved by a fifth. It is a reason to run a larger trial in healthy adults. Nobody has.

Reishi and sleep, and why calming is not sedating

Reishi is sold into the evening stack more than any other slot, so this needs saying plainly: no human trial has shown reishi acting as a sedative, and no human trial has measured sleep architecture with it at all. The Cochrane cancer review lists insomnia, not drowsiness, among the reported adverse events.

The sedative-like findings that circulate come from animal work. Yao and colleagues (2021), in Scientific Reports, gave mice 25 to 100 mg per kg of an acidic fraction of an alcohol extract of Ganoderma lucidum mycelium for 28 days and reported shorter sleep latency and longer sleeping time in pentobarbital-treated animals, alongside changes in hypothalamic serotonin signalling and gut bacteria. That is a mouse, an anaesthetic given alongside, and a mycelial fraction. It does not transfer to a person taking a capsule.

What can honestly be said is this. The traditional Chinese classification of lingzhi places it among the calming rather than the stimulating materials, and that is a statement about a text, not about a body. The one human signal pointing at felt state is the neurasthenia trial’s fatigue and wellbeing scales, at a very high dose, in patients. There is no pharmacological reason to avoid taking reishi in the evening, no evidence that the evening works better than the morning, and no basis for expecting it to make you sleepy. If you want it in an evening routine because that is when you remember to take things, that is a perfectly good reason.

The evening stack, and what has never been tested together

A red reishi, shiitake and shilajit capsule combines three materials with three quite different evidence bases, and the honest position is that no trial has tested the combination.

Shiitake, Lentinula edodes, has one well-run human trial worth naming. Dai and colleagues (2015), in the Journal of the American College of Nutrition, had 52 healthy adults aged 21 to 41 eat 5 g or 10 g of whole dried shiitake daily for four weeks and measured gamma delta T cell proliferation, NK-T cells, salivary IgA and CRP. Note the dose: 5,000 to 10,000 mg of whole mushroom. A 250 mg capsule fraction is not running that experiment, and shiitake sits in the blend as a culinary mushroom with a mild savoury character, not as the active from a trial.

Shilajit is the third component, and its human trials are audited in our shilajit benefits article. Ashwagandha, the other common evening pairing, has its stress-axis evidence covered in ashwagandha and cortisol, and lion’s mane, the usual daytime counterpart, in lion’s mane benefits. None of those pages can tell you what the combination does, because combination trials do not exist. Stacking is a convenience decision, not an evidence-based one, and a seller who calls a stack synergistic is describing a hope.

Reishi tea, and whether the traditional preparation is different

The benefits of reishi tea come up often enough to deserve their own answer, and the answer is chemical. A decoction, sliced bracket simmered in water for an hour, is a hot water extraction performed in your kitchen. It recovers polysaccharides reasonably well and triterpenes poorly, which is why a traditionally prepared reishi tea is less bitter than a strong ethanol extract. No trial used a home decoction, so every figure above applies to a standardised commercial preparation, not to your pot. Treat reishi tea as a drink you enjoy rather than as a dose you can quantify.

What is not established, and who should not take reishi

The evidence base is two Cochrane reviews that concluded against use for the questions they asked, one negative trial in healthy adults, one mostly negative trial in adults with borderline risk factors, one positive trial in patients with a psychiatric diagnosis at a very high dose, and a 2025 meta-analysis that rated the quality of evidence very low across every outcome it pooled. Under Regulation (EC) 1924/2006 no health claim for Ganoderma lucidum is authorised in the EU, and the botanical claims for it sit in the on-hold backlog of roughly 1,548 claims that the Commission and EFSA have never resolved. A page telling you reishi acts on a condition is making a claim it is not permitted to make.

The specific exclusions matter more than any benefits list.

Liver injury with powdered reishi. LiverTox, the NIH reference on medication-related liver injury, gives reishi a likelihood score of D, a possible rare cause of clinically apparent liver injury. The reported cases are hepatocellular, typically starting one to two months in, and almost all involve powdered preparations rather than extracts. They include a 78-year-old woman in China in 2004 who recovered over five months, a case in Japan in 2021 that resolved on stopping, and one fatal case in Thailand in 2007, a 47-year-old woman taking 200 mg of powder daily who developed jaundice at two months and died of multilobular necrosis. One death is one death, and it is one more than the efficacy literature has firmly established.

Anticoagulant and antiplatelet medication. Memorial Sloan Kettering lists reishi as raising bleeding risk alongside warfarin and similar drugs. No formal interaction trial exists, so the correct action is to ask your doctor or pharmacist before starting, not to guess.

Other prescribed medication. In laboratory work, reishi polysaccharides inhibited CYP2E1, CYP1A2 and CYP3A, the enzymes that clear a large share of prescription drugs. The clinical significance is unknown, which is why it is a question for a pharmacist.

Cancer treatment monitoring. Spore powder may raise the tumour marker CA72-4, which can confuse monitoring during cancer care. Tell your oncology team about anything you take.

Pregnancy and breastfeeding. Not tested. Avoid.

Children. Not tested. Not for them.

Autoimmune conditions and immunosuppressant medication. Reishi is taken specifically for its reported effect on immune markers, and nobody has studied it in people whose immune response is being deliberately suppressed. Speak to your specialist first.

Common complaints across the trials are nausea, dry mouth, constipation, vertigo and insomnia. In the Cochrane cardiovascular review, participants taking reishi for four months were 1.67 times as likely to report an adverse event as those on placebo, though none were serious.

So is reishi worth taking?

Three things decide it, and none of them is a benefits list. First, whether you can accept an evidence base whose two systematic reviews both concluded against use, and whose largest meta-analysis rates every outcome as very low certainty. Second, whether the jar in front of you states the part of the fungus, the extraction solvent and the standardisation, because without those three the milligram figure on the front compares to nothing. Third, whether you take prescribed medication, in which case the interaction questions above come before any question of benefit.

If that version of the answer is enough for you, reishi is a reasonable thing to try with modest expectations. Our red reishi, shiitake and shilajit capsules are sold on exactly that basis: what is in them, stated plainly, with no promise attached. If you are still working out how long to give a supplement before deciding whether it does anything, how long shilajit takes to work sets out the same reasoning for a different material, and it applies here too.