Reishi Mushroom (Ganoderma lucidum)
SupplementThe medical score (52) is notably lower than the community score (74), as clinical trials [s2, s5] show statistically significant but clinically small effects, and hepatotoxicity case reports [s13, s14] dampen the overall assessment. Community forum users [c1, c2] report subjectively more pronounced sleep and stress effects that have not been consistently replicated in RCTs.
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TL;DR
Reishi is the most clinically studied medicinal mushroom: a GRADE-rated meta-analysis (2025, 17 RCTs, n=971) shows significant effects on BMI, creatinine, and antioxidant markers — but effect sizes are small and study quality is mostly low to very low. Community reports on sleep, stress reduction, and immune support are consistent, yet clinical evidence remains weak. Critically, powdered reishi forms have been linked to hepatotoxicity cases — standardized extracts are clearly preferable over raw powder, and powder use should not exceed four weeks. In the EU, reishi is formally classified as Novel Food and technically requires authorization to be sold, though it is widely available in practice.
Description
Reishi (Ganoderma lucidum) is a traditional medicinal mushroom with immunomodulatory, adaptogenic, and antioxidant properties; clinical evidence for many applications remains limited [s1, s...
Reishi (Ganoderma lucidum), also known as Lingzhi or lacquered bracket fungus, has been used for millennia in traditional Chinese and Japanese medicine [s1]. The mushroom contains two main classes of active compounds: polysaccharides (primarily β-glucans), which mediate mainly immunomodulatory effects, and triterpenoids (ganoderic acids), which exert anti-inflammatory, antimicrobial, and potentially hepatoprotective effects [s3, s4]. Spores, fruiting bodies, and mycelium differ in composition: triterpenoids are preferentially found in the fruiting body, while polysaccharides are enriched in the mycelium [s3]. A GRADE-rated systematic review and meta-analysis from 2025 analyzed 17 RCTs with 971 participants and found significant reductions in BMI, creatinine, and heart rate under Ganoderma supplementation [s2]. For cancer patients, a Cochrane analysis is available (5 RCTs) showing improved NK cell activity and tumor markers, but no survival benefit [s5]. Small RCTs suggest adaptogenic effects on stress, fatigue, and sleep [s6, s7]. An RCT in breast cancer patients (1000 mg spore powder 3×/day, 4 weeks) showed significant improvements in fatigue and quality of life [s8]. A critical concern is hepatotoxicity: case reports, including a fatal case of fulminant hepatitis, have been associated with powdered Reishi (not aqueous extracts) [s13, s14]. The MSD Manual notes that the powdered form may be hepatotoxic with use exceeding one month [s9]. Quality issues in commercial products (undeclared fungal admixtures) have been documented by a German pharmacologist [s15].
Legal Status (DE)
In Germany, Ganoderma lucidum (Reishi) is classified as novel food under the EU Novel Food Catalogue and may generally not be sold as a food supplement without authorization [s12]. The joint expert commission BVL/BfArM has recorded Reishi in neutrally presented form as a food supplement, but considerable legal uncertainty remains [s11]. In practice, Reishi products are nonetheless sold in Germany; EU Novel Food authorization is formally required [s12]. In the USA, Reishi is considered a dietary supplement; β-glucans from Reishi mycelium are supported by a GRAS notice (GRN 413) [s10].
Mechanism of Action
Reishi contains several classes of active compounds with distinct mechanisms [s3, s4]: 1. Polysaccharides (β-1,3-glucans, β-1,6-glucans): Activate macrophages, dendritic cells, and NK cells via Toll-like receptors (TLR4) and Dectin-1. Promote cytokine release (IL-1β, IL-6, TNF-α) and modulate the adaptive immune system [s4]. 2. Triterpenoids (ganoderic acids A–Z): Inhibit the NF-κB signaling pathway, exert anti-inflammatory effects, and can induce apoptosis in tumor cells. Also inhibit 5α-reductase (relevant in BPH) and ACE (antihypertensive) [s3, s9]. 3. Sleep and stress modulation: Animal studies show that Reishi polysaccharides extend sleep duration by modulating gut microbiota — an effect attenuated by antibiotics (gut microbiota disruption). Whether this mechanism is relevant in humans remains unclear [s6]. 4. Antioxidant effect: Significant increase in glutathione peroxidase (GPx) in the meta-analysis (WMD = +2.29 U/ml, p < 0.001) [s2]. 5. Metabolic effects: Small but significant reductions in BMI (WMD = −0.43 kg/m²) and heart rate (WMD = −3.92 bpm) in pooled analysis [s2].
Dosing
Immunmodulation / allgemeine Gesundheit
- Dose
- 1,000–3,000 mg extract daily (standardized for polysaccharides and triterpenoids)
- Frequency
- 1–2× täglich
- Route
- oral
- Duration
- bis zu 12 Wochen
- Timing
- With meals
- With food
- empfohlen
Krebsunterstützung (adjuvant, nur unter ärztlicher Aufsicht)
- Dose
- Ganopoly 5.4 g/day (equivalent to ~81 g fruiting body) or spore powder 3,000 mg/day
- Frequency
- aufgeteilt auf 3 Dosen
- Route
- oral
- Duration
- 4–12 Wochen
- Timing
- With meals
- With food
- empfohlen
Schlaf und Stressreduktion
- Dose
- 1,000 mg extract daily
- Frequency
- 1× täglich abends
- Route
- oral
- Duration
- 4 Wochen
- Timing
- 30–60 minutes before bedtime
- With food
- optional
The Pharmacopoeia of the People's Republic of China recommends 6–12 g Reishi extract daily as an upper limit; Ganopoly studies used a maximum of 5.4 g/day over 12 weeks [s1]. Powdered form: use exceeding 1 month should be avoided due to hepatotoxicity risk [s9, s13].
Aqueous and alcoholic extracts differ substantially in composition: polysaccharides are water-soluble, while triterpenoids require alcohol extraction [s3]. Non-standardized powder products exhibit considerable quality variability [s15].
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Gastrointestinale Beschwerden (Übelkeit, Durchfall, Magenverstimmung) Documented in clinical studies and case reports; occurs primarily at higher doses [s1, s9]. | gelegentlich | leicht |
| Mundtrockenheit, Schwindel, Juckreiz Observed in clinical reports with polysaccharide extract administration [s1]. | gelegentlich | leicht |
| Erhöhung des Tumormarkers CA72-4 im Serum Reishi spore powder may elevate CA72-4, potentially leading to false-positive cancer findings [s9]. | gelegentlich | moderat |
| Hepatotoxizität (Leberschäden, cholestatische Hepatitis, fulminante Hepatitis) Multiple case reports describe acute liver injury up to fatal liver failure, particularly with powdered form used for >1 month [s13, s14]. Mechanism possibly immunoallergic [s14]. | selten | schwer |
| Erhöhte Blutungsneigung Reishi inhibits platelet aggregation in vitro; clinically relevant particularly in combination with anticoagulants [s9]. | theoretisch | moderat |
Contraindications
Hepatotoxicity risk from powdered reishi preparations documented by case reports, including fatal outcomes [s13, s14].
Additive bleeding risk due to antiplatelet activity of reishi; clinically documented [s9].
Reishi stimulates the immune system and may antagonize the effects of immunosuppressants [s9].
Insufficient safety data; contraindicated as a precautionary measure [s1, s9].
Antiplatelet effects increase perioperative bleeding risk; discontinuation at least 2 weeks before surgery is recommended [s9].
Additive blood pressure-lowering effect possible via ACE-inhibitory mechanism; monitoring recommended [s9].
Interactions
Synergistic
In a Cochrane analysis (5 RCTs), reishi as an adjunct to chemotherapy improved NK cell activity; no survival benefit demonstrated [s5].
Additive blood glucose-lowering effect; monitoring of glucose levels recommended [s9].
Reishi and cordyceps complement each other synergistically – reishi acts immunomodulatory and relaxing, while cordyceps enhances energy and physical endurance. The combination may provide broader immune support.
Reishi and chaga in combination show potentially additive antioxidant and immunostimulatory effects. Chaga provides potent antioxidants, while reishi acts primarily as an immunomodulator.
The combination of reishi and lion's mane links cognitive support with stress reduction and immunomodulation. Both mushrooms act as adaptogens and complement each other in their breadth of action.
Reishi and ashwagandha together may produce more comprehensive stress reduction than either adaptogen alone. Early studies with combination preparations report reduced perceived stress in adults.
Caution
Increased bleeding risk due to additive antiplatelet activity; medical supervision mandatory [s9].
Additive blood pressure reduction possible; risk of hypotension with combination [s9].
Reishi may antagonize immunosuppression; risk of rejection in organ transplant recipients [s9].
Additive hypoglycemia possible; blood glucose monitoring recommended [s9].
Both substances possess antiplatelet properties. The combination may additively increase bleeding risk, particularly at higher doses or prior to surgery.
Vitamin E at high doses (above 400 IU) exerts anticoagulant effects. In combination with reishi, bleeding risk may increase additively; the combination should be discontinued prior to surgery.
Curcumin has well-known antiplatelet properties. The combination with reishi may potentiate bleeding risk, especially with concurrent use of anticoagulants.
Both substances have blood glucose-lowering properties. The combination may lead to additive hypoglycemia; regular blood glucose monitoring is recommended.
Studies
Tier A — High Evidence
Outcome: Tumor response, NK cell activity, survival rate in cancer patients
Effect Size: Significant increase in NK cell activity (34.5% vs. 26.6% baseline); no survival benefit
Outcome: Fatigue, quality of life in breast cancer patients (spore powder 3,000 mg/day)
Effect Size: Significant improvement in physical function and fatigue (p<0.05)
Outcome: BMI, creatinine, GPx, heart rate under Ganoderma supplementation
Effect Size: BMI: WMD −0.43 kg/m² (p=0.011); GPx: WMD +2.29 U/ml (p<0.001); HR: WMD −3.92 bpm (p=0.029)
Tier B — Moderate Evidence
Outcome: Anxiety (PSS), stress, well-being
Effect Size: Significant anxiety reduction; individual reishi effect not isolable
Outcome: Mood, sleep quality, cortisol in young adults
Effect Size: Modest improvement in stress, fatigue, and sleep; individual effect of reishi not isolated
Tier C — Low Evidence
Outcome: Mechanisms of polysaccharides, triterpenoids, peptides
Effect Size: Narrative review; no independent effect sizes
Outcome: Immunological pathways, antioxidant mechanisms
Effect Size: Narrative review; no independent effect sizes
Community Evidence
Top reported benefits
- Better sleep quality and more vivid dreams
- Subjectively improved immune defense (fewer colds)
- Relaxation and stress reduction in the evening
- Greater calmness and reduced anxiety
Top reported issues
- Unclear product quality and standardization
- No perceptible effect in some users
- Concerns about hepatotoxicity after reading case reports
- Bitter taste with powder products
Several community members express concerns about hepatotoxicity with powder forms and emphasize the importance of quality products (extracts rather than raw powder). Some users report no noticeable effect with lower-cost products lacking quality certification [c1, c2, c3].
Scientific Sources
- Ganoderma lucidum (Lingzhi or Reishi)
Boh B, Berovic M, Zhang J, et al. (2007). NCBI Bookshelf (Herbal Medicine: Biomolecular and Clinical Aspects)BLink - Are Functional Mushrooms GRAS for Food? – FDA GRAS Notice GRN 413
Dicentra Regulatory Services (2023). Dicentra / FDA GRAS DatabaseALink - Erste Stellungnahme der Gemeinsamen Expertenkommission BVL/BfArM zu Vitalpilzen als Nahrungsergänzungsmittel (Nr. 01/2014)
BVL/BfArM Expertenkommission (2014). Bundesamt für Verbraucherschutz und Lebensmittelsicherheit / BfArMALink - Vitalpilze für die Krebstherapie? – Verbraucherzentrale
Verbraucherzentrale Deutschland (2023). Verbraucherzentrale.deBLink - Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder
Wanmuang H, Leopairut J, Kochakarn W, et al. (2007). Journal of the Medical Association of ThailandCPMID:17621752 - Hepatotoxicity due to a formulation of Ganoderma lucidum (lingzhi)
Wachtel-Galor S, Tomlinson B, Benzie IF (2004). Journal of HepatologyCPMID:15464254DOI - Pharmakologe über Vitalpilze – 'Für Pilzpräparate sind keine wirksamen Inhaltsstoffe bekannt'
Deutschlandfunk Redaktion (2023). DeutschlandfunkCLink - The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials
Jafari S, Haghighat N, Rezaei M, et al. (2025). Food Science & NutritionAPMID:40510787DOI - A review of Ganoderma lucidum: Cultivation, active ingredients and its application as functional ingredients
Xie J, Zhao L, Liu Y, et al. (2025). Food ChemistryBDOI - A Review of Bioactive Components and Pharmacological Effects of Ganoderma lucidum
Huang Y, Zhang H, Chen X, et al. (2025). PMC / FrontiersBLink - Ganoderma lucidum (Reishi mushroom) for cancer treatment (Cochrane Review)
Jin X, Ruiz Beguerie J, Sze DM, et al. (2016). Cochrane Database of Systematic ReviewsADOI - Mood and Sleep Benefits of Mushroom Supplementation in Young Adults: An Exploratory Randomized Double-Blind Placebo-Controlled Trial
Iannitti T, Rottigni V, Palmieri B, et al. (2024). Longdom PublishingBLink - Adaptogenic Effects of Mushroom Blend Supplementation on Stress, Fatigue, and Sleep: A Randomised, Double-Blind, and Placebo-Controlled Trial
Harada T, Onoda K, Kato S, et al. (2025). PMCALink - Clinical Evidence for the Use of Ganoderma lucidum Medicinal Mushroom
Lucius K (2025). Integrative Cancer TherapiesBDOI - Reishi – MSD Manual Profi-Ausgabe
MSD Manual Editorial Board (2024). MSD Manual Profi-AusgabeBLink
Community Sources
Storage
Unopened
Store in a cool, dry place (15–25 °C), protected from direct sunlight and moisture.
Opened
Keep container tightly closed; protect powder forms especially from moisture to prevent clumping.
Notes
Alcoholic extracts are more stable than aqueous powder forms. Quality variation between commercial products is considerable; choose standardized extracts specifying polysaccharide and triterpenoid content [s15].