Reishi and sleep: what the research shows

Reishi has a way of turning up in places that don't obviously belong together: a bedtime-tea shelf, a "calm" mushroom coffee, a capsule bottle next to the lion's mane. The label promises relaxation. The research is a little more specific, and a lot more patchy. Let's look at what reishi is, what has been tested in people, and what's worth knowing before it goes in your basket.

Does reishi help you sleep? The human evidence is a single blend

Reishi (Ganoderma lucidum, also sold as lingzhi) is a long-used medicinal fungus with interesting chemistry, and its calming reputation comes mainly from tradition and mouse experiments. The only human trial we know of that measured sleep tested a company-funded blend of five mushrooms, so it can't tell you what reishi does by itself. No trial of reishi alone with sleep as the main outcome turned up. The best-known reishi trial measured fatigue and well-being in people diagnosed with neurasthenia, and it used a polysaccharide extract rather than the whole mushroom. That mismatch is why this page covers what reishi is and what to check on a label as well as sleep. Short trials report few problems, but there are liver case reports and a few cautions worth knowing.

Reishi, meet the label: what is it, exactly?

Reishi is a woody, glossy-capped bracket fungus. In Chinese medicine it is lingzhi; in Japan, reishi. Even the Latin name is less settled than the shelf labels suggest. A 2023 taxonomic study in the Journal of Fungi (Du et al., 2023) concluded that the widely cultivated Chinese lingzhi has long been misidentified as G. lucidum, and argued its correct name is G. sichuanense, with G. lingzhi a later synonym. Naming is still debated. The practical upshot is that a pack saying "Ganoderma lucidum", "G. lingzhi" or just "reishi" may not describe exactly the same organism, and published trials don't always say which one they used. Some case reports in the safety literature use G. lingzhi for the same everyday powder.

Two groups of compounds dominate the conversation. Reviews describe polysaccharides (including beta-glucans) and triterpenoids as the main bioactive components, alongside peptides, proteins and sterols (Ren et al., 2025, Food Science & Nutrition). The same review notes that few of these compounds have been clinically validated as better than existing treatments. A 2026 review in Pharmaceuticals (Qu et al.) adds that laboratory activity often fails to carry over to living systems because the signature triterpenoids and polysaccharides are poorly absorbed, and says no reishi nanoformulation had reached human trials.

Where the calming reputation comes from

Tradition comes first. Reishi has been used in East Asian medicine for roughly two thousand years, and "calming the spirit" is part of that vocabulary. It's a cultural history worth knowing about, though it isn't a clinical result.

Then there are the animal studies. A 2024 mouse study in Heliyon (Li et al., 2024) compared different Ganoderma recipes. One blend (reishi extract, broken spore powder and G. sinense powder) shortened the time mice took to fall asleep, from 6.8 to 4.2 minutes, and lengthened sleep duration from 88.3 to 152.5 minutes. A different recipe containing reishi extract did better on a swimming test than on sleep. The authors' own conclusion is that the effect depends on how the reishi is prepared, which is a useful finding for shoppers, though it comes from mice, not people.

The mechanisms you may see on packs (GABA, serotonin, TNF-alpha, the stress axis) come from lab and animal work or from reviews of it. We've left them out of the explanation because no human sleep data tests them.

What has been tested in people

This is the part that matters most for the "calming" claim, so here it is one trial at a time.

Neurasthenia, fatigue and well-being. Tang and colleagues (2005, Journal of Medicinal Food) randomised 132 Chinese patients diagnosed with neurasthenia to a G. lucidum polysaccharide extract (a product called Ganopoly) or placebo, at 1,800 mg three times a day for eight weeks. Of 123 patients assessed, the extract group had lower clinical-severity and fatigue scores than the placebo group, and about half (32 of 62) were rated more than minimally improved against 15 of 61 on placebo. Sleep was not the primary outcome. It is a single, fairly old trial of one branded extract in a specific diagnosis, and the paper's summary doesn't name the funder, so it doesn't tell a general shopper what to expect.

A five-mushroom blend. A 2026 randomised trial in Brain and Behavior (Hisamuddin et al.) gave 50 participants either a proprietary blend or a placebo, with sleep measured on the Pittsburgh Sleep Quality Index among several outcomes. The authors reported better anxiety, stress, fatigue and sleep-quality results in the blend group. The blend contained lion's mane, Cordyceps militaris, reishi, shiitake and maitake, and the study was funded by NexusWise Sdn Bhd. A reishi-only effect can't be pulled out of that, so it counts as evidence about the blend.

Blood sugar and heart-risk markers. A Cochrane review of G. lucidum for cardiovascular risk factors (Klupp et al., 2015) found five eligible trials with 398 participants in total. A later 84-person randomised trial in people with type 2 diabetes and metabolic syndrome, at 3 g a day of reishi, with or without Cordyceps sinensis, for 16 weeks (the two active arms were analysed together), found no effect on blood glucose or the secondary measures (Klupp et al., 2016). So "reishi for metabolic health" doesn't have a trial behind it either.

Cancer. A Cochrane review (Jin et al., 2016) found five randomised trials of generally poor quality, concluded there was not enough evidence to justify reishi as a first-line cancer treatment, and said it could be used as an adjunct to conventional therapy for its possible effect on tumour response and immune measures. Anyone in cancer treatment should treat that as a conversation for their oncology team, not a shopping tip.

Sleep on its own. No placebo-controlled trial of reishi alone in healthy adults or people with insomnia turned up. That fits what recent reviews describe as thin human evidence.

"Reishi 500 mg": what the number on the pack is a number of

"Reishi" on a label can mean several different things. This table covers what's worth asking about, not a ranking.

• What the label may say: Fruiting body powder; What it usually means: Ground mushroom body; What to look for: Which species name is printed; whether anything is said about the polysaccharide or triterpene content
• What the label may say: Extract; What it usually means: Concentrated preparation, often hot-water or hot-water-plus-alcohol; What to look for: Extraction method, the extract ratio, and whether the figure on the front is the extract weight or the raw mushroom weight
• What the label may say: Spore powder or spore oil; What it usually means: From the spores, which are tiny and tough; What to look for: Whether the shell is broken, and what exactly is being claimed
• What the label may say: Mycelium (often on grain); What it usually means: The fungus's thread-like growth, not the mushroom body; What to look for: The word "mycelium" in the ingredient list; see the EU note below
• What the label may say: Tea, coffee or blends; What it usually means: Reishi plus other ingredients; What to look for: The amount of reishi per serving, which is often not stated

A worked, invented example shows why this matters. A pack says "Reishi 500 mg, 10:1 extract". That could mean 500 mg of extract made from about 5 g of mushroom, or 500 mg of mushroom in total. The pack should say which. The trials above used amounts from 1.5 g to 5.4 g a day of different preparations (a figure each paper reports for its own participants, not a target), so the number on your label is only meaningful once you know what it is a number of. Our guide to how to read supplement labels walks through that kind of check.

Safety: the parts worth taking seriously

Most short trials report few problems. A 2007 trial of 16 healthy volunteers taking 2 g of extract twice a day for ten days found no adverse effects compared with placebo (Wicks et al.). Short and small is the keyword, though.

Liver. The case literature is the reason this page has a safety section. A Hong Kong case in 2004 (Yuen et al.) was the first report of liver toxicity linked to a G. lucidum formulation, and a Thai team described a fatal fulminant hepatitis in a patient who had switched from boiled lingzhi to powder one to two months earlier (Wanmuang et al., 2007). Both patients were also taking other treatments, so a causal link is suggestive rather than proven. A 2023 case report (Guedikian et al., Cureus) described a 47-year-old man with acute hepatitis after reishi powder and alcohol; he recovered fully after conservative treatment. Case reports can't tell us how common this is. Memorial Sloan Kettering's patient page on reishi (last updated 5 May 2026) also lists liver injury among possible effects, and notes one fatality linked to powdered reishi.

Reports to pharmacovigilance. A 2025 analysis of the WHO's VigiBase safety database (Liang et al., Pharmaceuticals) found G. lucidum was the most frequently reported single-ingredient product among the natural products studied, and one of the three most often linked to serious reports. The most common reports for reishi were chills, chest pain, fever and skin reactions (itching, rash, redness, sweating), followed by nausea, vomiting and abdominal pain. The authors say causality often couldn't be established, and report counts partly reflect how widely a product is used. The analysis covers adaptogenic and immune-supporting products in general, not reishi alone, so it works as a reason for caution rather than a measure of risk.

Bleeding and blood thinners. Memorial Sloan Kettering advises people on blood thinners such as warfarin to speak to their healthcare provider because reishi can increase bleeding risk. The human data are less alarming: in a randomised trial of 40 healthy volunteers taking 1.5 g a day for four weeks, clotting tests and platelet function stayed normal and did not differ from placebo (Kwok et al., 2005). Healthy volunteers are not people taking warfarin, so the sensible reading is to ask a pharmacist before combining. Our supplement and drug interactions guide covers how to raise that conversation.

Other situations. Memorial Sloan Kettering also says people on immunosuppressants should talk to their provider first. There is no reliable safety data for pregnancy or breastfeeding. If you have liver disease, take prescription medicines, are having surgery, or are in treatment for cancer, speak to your doctor or pharmacist before trying reishi.

Reishi in the Netherlands and the EU, read 8 October 2026

Rules change, so check the current position.

• Dutch herbal rules. The Warenwetbesluit Kruidenpreparaten bans certain plants and fungi listed in its annex. Ganoderma is not named in the annex (consolidated text on wetten.overheid.nl, in force since 1 July 2022), which says nothing about authorisation either way.
• EU novel food rules. A 2019 consultation document on the European Commission's site records that Ganoderma lucidum dehydrated mycelium powder was assessed as a novel food in the EU, because a history of consumption before 15 May 1997 couldn't be shown for the mycelium. The same document says the fruiting body (carpophore) does have a history of safe and significant consumption before that date. That is a 2019 record for one product type, so check the Commission's Novel Food Status Catalogue for extracts and spore products. If a pack lists mycelium, ask the seller or the Dutch food authority (NVWA).

What reishi is worth, for sleep and otherwise

For sleep specifically, reishi is an interesting ingredient with no clear trial result to point to, whatever the front of the pack says. The animal data are encouraging but come from mice, and the strongest human data are about fatigue in one diagnosis, using one extract. If a product leans on sleep claims, read them as marketing language rather than a finding. If you're curious about reishi for its own sake, the useful questions are the ones in the label table above, plus a check against your medicines.

For sleep itself, everyday habits have the better-established track record; our sleep hygiene guide is a good place to start. And for the general rules of reading a supplement pack, see Smart Supplements 101.

Where to read next

Reishi sits alongside other calming-reputation ingredients and mushrooms:

• Functional mushrooms and adaptogens: guide hub, for the six popular ingredients, each with its own guide, and a place to start.
• Cordyceps: fungus, formulations and performance claims, for which species the endurance trials used and the Dutch position as read on 8 October 2026.
• Sleep supplements: ingredients before the promise, for what the label lists, what studies say each ingredient does for sleep and what NL and EU rules allow.
• Ashwagandha: the plant behind the stress and sleep claims, for what the trials tested, what "adaptogen" means and the liver and thyroid cautions.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 12 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.