Reishi
Ganoderma lucidum · Lingzhi · "Spirit Mushroom"
Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.
The strongest human data is the 2016 Cochrane review (Jin et al., CD007731.pub3), which pooled 5 RCTs and 373 participants and concluded there is insufficient evidence to justify Ganoderma lucidum as a first-line cancer treatment. It found no long-term survival benefit and only a non-significant signal for tumor response when added to chemo/radiotherapy (RR 1.50, 95% CI 0.90 to 2.51), plus modest improvements in T-lymphocyte subsets and Karnofsky quality-of-life scores. The authors rated the evidence very low quality because of unclear randomization and small samples. A separate placebo-controlled beta-glucan RCT in healthy adults reported increased NK-cell cytotoxicity and immunoglobulin A, but it is preliminary and single-study. Sleep and stress benefits rest on tradition and small trials. So the honest grade for the supported immune-adjunct signal is preliminary/observational, a 2, not the 3 currently assigned; the traditional and marketed halo runs well ahead of the trial base.
- FDA
- Legal supplement (DSHEA)
- WADA
- Not prohibited
Reference only. Not medical advice.
What can go wrong
Documented liver injury including a fatal fulminant case tied to powdered reishi, plus antiplatelet activity that is a real concern with anticoagulants and pre-surgery; boiled traditional forms have the cleaner safety record.
Reishi carries perhaps the deepest documented traditional pedigree in the supplement world. The Shennong Bencaojing, compiled in Han-dynasty China around two thousand years ago, ranked lingzhi among the "superior" herbs, the top tier of tonics thought safe for prolonged use. Modern science has confirmed real bioactive compounds, triterpenes and beta-glucans, with plausible immune-modulating mechanisms. The human trial evidence is thinner than the reputation suggests: a 2016 Cochrane review of 5 RCTs found insufficient evidence for first-line cancer use, with only a weak, non-significant adjunct signal alongside conventional therapy. Sleep and calm benefits are widely reported but preliminary, and there are documented cases of serious liver injury, including a fatal one, tied to powdered preparations.
A two-thousand-year traditional inheritance and a real modern mechanism.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
Reishi (Ganoderma lucidum) contains two major bioactive fractions: beta-glucan polysaccharides (immune-modulating, particularly through dectin-1 and TLR pathways on macrophages and natural killer cells) and triterpenes (ganoderic acids, with antioxidant, hepatoprotective, and antiplatelet activity). The mushroom is non-edible (woody texture) and is consumed as decoction, extract, or powdered form. The triterpenes drive much of the calming and sleep effects; the polysaccharides drive the immune-modulatory profile.
How it is taken
Clinical trials have most often used standardized extracts in the range of roughly 1.5 to 3 grams per day, divided into two or three doses. Several cancer and immune studies used a polysaccharide-rich extract (marketed as Ganopoly) at about 1,800 mg three times daily for around eight weeks. The fruiting-body extract is the form studied in most human trials; mycelium-grown-on-grain products can be diluted with residual starch and are not equivalent. Dual-extraction (water plus alcohol) products aim to capture both the water-soluble beta-glucans and the alcohol-soluble triterpenes. Dose appears to matter for bleeding risk: reports suggest platelet aggregation is not inhibited at about 1.5 g daily but can be at about 3 g daily. This is informational consumer guidance drawn from the trial literature, not a prescription. Anyone considering reishi, especially during cancer treatment, on blood thinners, or with liver concerns, should confirm the plan with a qualified clinician first.
Safety in detail
- Documented antiplatelet activity, real concern with warfarin, antiplatelet drugs (aspirin, clopidogrel), and pre-surgical use. Discontinue 1-2 weeks before elective procedures.
- Rare hepatotoxicity case reports; baseline liver panel reasonable for long-term use.
- Mycelium-on-grain products are common in the supplement aisle but lack the studied bioactive content of fruiting body extracts.
- GI upset, dryness of mouth, and dizziness are the most commonly reported side effects.
- Allergic reactions are rare but possible.
What people get wrong
Often saidReishi is just a sleep aid.
ActuallyTraditional use is much broader, calming, immune, longevity, "shen" (spirit) support. Modern evidence is strongest for sleep and immune adjuvant; the broader claims are mechanism-supported but outcome-evidence-limited.
Often saidAny reishi product is equivalent.
ActuallyFruiting body extract differs substantially from mycelium-on-grain in beta-glucan and triterpene content. Reading labels matters.
Often saidReishi has no interactions.
ActuallyDocumented antiplatelet activity is real. Warfarin, aspirin, clopidogrel, and pre-surgical caution all apply.
Who profits, and who pushes back
Cochrane Collaboration / Jin team
The cancer evidence is suggestive but limited by trial quality. We cannot recommend reishi as a first-line cancer treatment. The adjuvant immune-modulatory possibility is real but requires more rigorous trials.
Christopher Hobbs
Independent voice on traditional and modern uses; reference text in the functional mushroom space.
Paul Stamets
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
Major mycology voice and brand owner. Brings real expertise; financial stake in functional mushroom supplements.
Daniel Winkler
Independent ethnomycologist on traditional Asian medicinal mushroom use and supply chains.
Where the research comes from
| Place | Share of published research |
|---|---|
| China | 42% |
| Japan | 24% |
| Korea | 18% |
| Western research | 16% |
Research published from: China.
How we got here
Reishi (灵芝, lingzhi, "spirit mushroom") appears in the Shennong Bencaojing (神农本草经, dated to roughly 200 CE), the foundational text of traditional Chinese herbal medicine. It is classified there as a "superior" herb, the highest of three tiers, reserved for tonics safe for prolonged daily use. Two thousand years of continuous documented use is among the deepest traditional inheritances of any compound in the supplement world.
- ~200 CEShennong Bencaojing classifies reishi as "superior" herb
- 1971Yukio Naoi achieves reliable cultivation, ending wild-harvest dependence
- 1990sModern beta-glucan immunology characterizes mechanism
- 2012Chen sleep quality trial
- 2016Cochrane review on cancer indications
- 2020sFunctional mushroom mainstreaming in Western wellness
What we do not know
- Whether the cancer-adjuvant signal from Asian trials replicates in Western clinical populations and oncology protocols.
- Whether triterpene-standardized extracts produce meaningfully different effects than polysaccharide-standardized extracts for specific use cases (sleep vs immune).
- Whether dual-extracted (hot water + alcohol) products are clinically superior to single-extraction products for everyday consumers.
- Optimal dose for sleep and stress applications, most studied doses are higher than commercial product recommendations.
Legal status
Universally available as a dietary supplement worldwide. Long traditional use in East Asian medical systems. PSP and other fungal polysaccharide products are approved cancer adjuvant drugs in some Asian markets but not in the US. Generally no regulatory restrictions on supplement-grade products.
Status current as of July 2026. Regulatory positions change, sometimes quickly.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Fruiting body extract is the studied form and the form with bioactive content matching traditional use. Mycelium-on-grain ("Myceliated grain") products are common, cheap, and often labeled identically, but contain minimal beta-glucan and triterpene content. Dual-extracted (hot water + alcohol) products capture both polysaccharide and triterpene fractions. Country of origin (China, Japan, Korea, US-grown) reflects different cultivar and quality traditions.
At a glance
- Active fractions
- Beta-glucans, ganoderic acids (triterpenes)
- Typical dose
- 1-3g/day extract
- Studied form
- Fruiting body extract, dual-extracted
- Traditional classification
- Shennong "superior" herb
- Traditional use
- 2000+ years documented
- Key interaction
- Anticoagulants, antiplatelets
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Reishi. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
Sources
Cochrane review of 5 RCTs (373 participants) found insufficient evidence for first-line cancer use, no survival benefit, non-significant tumor-response signal (RR 1.50, 95% CI 0.90-2.51), modest T-lymphocyte and quality-of-life changes.
Cochrane Database of Systematic Reviews (Jin X et al., CD007731.pub3), via PMC
Summary of the Cochrane review: insufficient evidence to justify Ganoderma lucidum as first-line cancer treatment; possible adjunct role.
Fatal fulminant hepatitis reported after a patient switched to powdered lingzhi, having tolerated boiled lingzhi previously.
Reishi-powder-associated acute liver injury (ALT 990) in the setting of heavy alcohol use; literature review of prior hepatotoxicity cases and the boiled-vs-powder pattern.
Reishi Mushroom-Induced Acute Liver Injury case report and review, via PMC
Antiplatelet activity of ganoderic acids, reported prolongation of INR/PT/APTT, warfarin-interaction observation, and dose-dependent platelet effects (not at ~1.5 g/day, yes at ~3 g/day).
Memorial Sloan Kettering Cancer Center, About Herbs: Reishi Mushroom
Randomized placebo-controlled trial of Ganoderma-derived beta-1,3;1,6-D-glucan in healthy adults reporting increased T-cell subsets, NK-cell cytotoxicity and IgA, well tolerated with no significant liver/kidney marker changes.
Main bioactives (triterpenes/ganoderic acids and beta-glucan polysaccharides), receptor engagement, and typical clinical dosing of ~1.5-3 g/day extract.
Double-blind placebo-controlled RCT of Ganoderma lucidum for metabolic syndrome cardiovascular risk factors found no significant benefit, illustrating limits of clinical evidence beyond cancer.
Cholestatic liver injury from a Ganoderma lucidum coffee-extract product, supporting the pattern of hepatotoxicity from concentrated preparations.
Traditional origins: Shennong Bencaojing classed lingzhi as a superior herb; Li Shizhen's Bencao Gangmu described lingzhi varieties; cultivation developed in the twentieth century.
Ganoderma lucidum review, Herbal Medicine: Biomolecular and Clinical Aspects (NCBI Bookshelf)
The studies that matter
Cochrane review Jin2016
Insufficient evidence for first-line cancer treatment; possible adjuvant immune-modulatory benefit when added to conventional chemotherapy in some cancer types.
Chen sleep quality and fatigue trial2012
Reishi extract improved subjective fatigue, irritability, and sleep quality in neurasthenia patients over 8 weeks.
Wang G. lucidum cancer adjuvant meta-analysisMultiple
Suggested improved tumor response and immune parameters when added to chemotherapy; methodological quality of underlying trials is variable.
Tang lipid and antioxidant trialsMultiple
Modest improvements in metabolic markers; clinical significance modest.