Reishi

Metadata

Regulatory Status

Chinese Pharmacopoeia

• Listed: Yes. Lingzhi (Ganoderma) is an official drug in the Chinese Pharmacopoeia (2020 edition), covering both G. lucidum and G. sinense.
• Traditional indications: Replenishing qi, easing the mind (an shen), relieving cough and asthma. Indicated for dizziness, insomnia, palpitations, and shortness of breath.
• Classification: Superior-grade herb in the Shennong Bencao Jing (Divine Farmer’s Classic of Materia Medica, circa 200 CE), indicating suitability for long-term use to promote health and longevity without toxicity.

Japanese Pharmacopoeia and Kampo

• Recognition: Reishi (Mannentake) is established in Japanese traditional Kampo medicine and widely available as a health food and dietary supplement.
• Traditional use: Promotion of vitality, immune support, liver function support, and longevity.
• Market status: Japan represents one of the largest global markets for reishi products, with extensive commercial cultivation infrastructure.

Korean Traditional Medicine

• Recognition: Yeongji is documented in Korean traditional medicine texts, including the Dongui Bogam (1613 CE), the seminal Korean medical encyclopedia.
• Traditional use: Used to nourish the heart, calm the spirit, and strengthen qi. Classified as a longevity tonic.

European Union

• EMA/HMPC: No monograph or assessment report. Reishi falls outside the European phytotherapy tradition evaluated by these bodies.
• Novel Food: Some reishi preparations have received novel food authorization in EU member states under Regulation (EU) 2015/2283. Status varies by preparation type and member state.
• Commission E / ESCOP: No monographs exist.

United States

• Dietary supplement: Widely marketed under DSHEA (Dietary Supplement Health and Education Act of 1994).
• FDA GRAS: No specific GRAS determination for reishi extracts, though products are commonly incorporated into functional foods and beverages.

Western Integrative Medicine

• Reishi is increasingly incorporated into integrative oncology protocols, particularly as an adjunctive immune support agent during and after conventional cancer treatment. The Society for Integrative Oncology acknowledges mushroom beta-glucans as an area of active research.

Conditions & Indications

Primary Indications (Moderate-to-Good Evidence)

• Immune modulation and immunodeficiency — Beta-glucan polysaccharides activate innate immune cells (macrophages, NK cells, dendritic cells) via Dectin-1 and complement receptor 3 (CR3). Multiple controlled trials demonstrate measurable enhancement of immune cell counts and activity in both cancer patients and healthy individuals.
• Cancer adjunctive therapy (quality of life, immune support, fatigue) — The Cochrane systematic review by Jin et al. (2012) evaluated five RCTs (n=373) and found that reishi, when used alongside conventional cancer treatment, improved quality of life, enhanced immune cell parameters (CD3, CD4, CD8, NK cell activity), and reduced cancer-related fatigue. No direct antitumor effect was demonstrated as monotherapy.
• Adaptogenic stress response — Traditional classification as a superior-grade shen tonic in TCM, supported by preclinical evidence of HPA axis modulation, anxiolytic activity, and improved stress resilience in animal models.

Secondary Indications (Preliminary Evidence)

• Sleep disturbances and insomnia — Traditional TCM indication (an shen, calming the spirit), supported by adenosine content and preclinical sedative effects. Cui et al. (2012) demonstrated increased total sleep time and non-REM sleep in rodents. Human evidence remains limited to traditional use reports and small uncontrolled studies.
• Cardiovascular support (lipid modulation, blood pressure) — Ganoderic acids and polysaccharides demonstrate lipid-lowering and antihypertensive effects in animal models. However, the Klupp et al. (2015) Cochrane review of five RCTs (n=398) found no statistically significant effects on fasting glucose, HbA1c, blood pressure, or lipid profiles versus placebo.
• Hepatoprotection — Ganoderic acids demonstrate liver-protective effects in animal models of chemical liver injury, reducing serum transaminases and modulating inflammatory pathways.

Emerging/Preclinical Indications

• Anti-allergic and anti-histamine effects — Ganoderic acids C and D inhibit histamine release from mast cells via suppression of IgE-mediated degranulation in vitro and in animal models of asthma and allergic rhinitis.
• Anti-diabetic activity — Reishi polysaccharides (ganoderans A and B) show hypoglycemic activity in diabetic animal models through enhanced insulin sensitivity and glucose metabolism modulation. Limited pilot data in humans.
• Gut microbiome modulation — Chang et al. (2015) demonstrated that reishi mycelium water extract altered gut microbiota composition in high-fat diet mice, reducing the Firmicutes-to-Bacteroidetes ratio and improving metabolic markers, published in Nature Communications.

Mechanism of Action

Primary Mechanisms

1. Beta-glucan activation of innate immunity Reishi beta-1,3/1,6-D-glucan polysaccharides are recognized by pattern recognition receptors on innate immune cells, principally Dectin-1 (CLEC7A) on macrophages and dendritic cells and complement receptor 3 (CR3/CD11b/CD18) on neutrophils and NK cells. Receptor binding triggers NF-kB and MAPK downstream signaling cascades, resulting in enhanced phagocytic activity, pro-inflammatory cytokine production (TNF-alpha, IL-1beta, IL-6, IL-12), and augmented NK cell cytotoxicity. This immune-stimulatory mechanism is the most clinically validated pathway and the principal basis for cancer adjunctive therapy applications.

2. Ganoderic acid triterpenoid activity Over 150 oxygenated lanostane-type triterpenoids (ganoderic acids) have been isolated from reishi. These compounds exert multiple pharmacological effects through distinct mechanisms:

• Anti-inflammatory: Inhibition of NF-kB signaling and suppression of COX-2 expression, reducing pro-inflammatory cytokine release.
• Hepatoprotective: Reduction of hepatic oxidative stress markers and modulation of phase I/II detoxification enzyme activity.
• Anti-histamine: Ganoderic acids C and D inhibit histamine release from mast cells through suppression of IgE-mediated degranulation signaling.
• Cytotoxic (preclinical only): Direct cytotoxicity against select cancer cell lines in vitro via apoptosis induction and cell cycle arrest, though clinical translation remains unestablished.

3. Adenosine-mediated sedative and cardiovascular effects Reishi contains adenosine and structurally related nucleosides that contribute to its calming and cardiovascular properties. Adenosine promotes sleep through activation of A1 and A2A receptors in the basal forebrain, inhibiting cholinergic wake-promoting neurons. It also mediates coronary and peripheral vasodilation and inhibits platelet aggregation via A2A receptor signaling on platelet surfaces.

Key Active Compounds

Pharmacological Note

Reishi’s pharmacological profile is best understood as a dual-action system: water-soluble polysaccharides (extracted by traditional hot water decoction) drive immune modulation, while alcohol-soluble triterpenoids (extracted by ethanol) drive anti-inflammatory, hepatoprotective, and anti-histamine effects. Traditional decoction methods extract primarily polysaccharides; modern dual-extraction products capture both compound classes. The extraction method fundamentally determines the pharmacological profile of the final product, which has critical implications for clinical standardization and therapeutic application.

Clinical Evidence Summary

Clinical evidence for reishi is moderate-to-good in quality, concentrated primarily in cancer adjunctive therapy and immune modulation. Most clinical trials originate from Chinese and Japanese research groups.

Systematic Reviews and Meta-Analyses

Key Individual Trials

Evidence Limitations

• The Cochrane review (Jin et al. 2012) found that no included trial assessed reishi as a sole anticancer agent; all were adjunctive to conventional therapy.
• Most positive trials used the proprietary Ganopoly polysaccharide extract, limiting generalizability to other reishi products.
• The Wachtel-Galor (2004) trial in healthy volunteers showed no significant immune effects at 4 weeks, suggesting that effects may be more pronounced in immunocompromised populations or require longer treatment durations.
• The Klupp (2015) Cochrane review found no significant cardiovascular benefits, failing to confirm earlier preliminary reports.
• Sample sizes are generally small (n=18-96) with short treatment durations (4-12 weeks).
• Standardization and quality control of reishi products vary widely across studies, complicating cross-trial comparisons.
• Publication bias is a concern, particularly for Chinese-language trials not captured in English-language systematic reviews.

Safety Profile

General Assessment

Reishi has been consumed for over 2,000 years in traditional medicine and is generally considered well-tolerated at standard doses. The Cochrane review (Jin et al. 2012) reported no major adverse events across the five included RCTs. However, systematic long-term safety data from large controlled trials are limited, and isolated cases of hepatotoxicity have been reported.

Contraindications

• Autoimmune disease: Due to immune-stimulating properties, reishi should be used with caution in patients with autoimmune conditions (systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease). Immunomodulation could theoretically exacerbate autoimmune activity, though clinical case reports documenting this interaction are absent.
• Bleeding disorders or thrombocytopenia: Reishi has demonstrated antiplatelet activity through adenosine-mediated inhibition of platelet aggregation and inhibition of thromboxane A2 synthase. Avoid in patients with existing bleeding disorders.
• Pre-surgical: Discontinue at least 2 weeks before scheduled surgery due to antiplatelet activity and potential interactions with anesthetic agents.
• Pregnancy and lactation: Insufficient human safety data. No human studies have been conducted in pregnant or lactating women. Avoid until safety is established.

Drug Interactions

• Anticoagulants and antiplatelets (warfarin, heparin, aspirin, clopidogrel): Reishi demonstrates antiplatelet activity through adenosine-mediated inhibition of platelet aggregation and inhibition of thromboxane A2 synthase. Concomitant use may increase bleeding risk. Case reports document elevated INR in patients taking warfarin concurrently with reishi supplements. Severity: Moderate-to-high. Monitor INR closely.
• Immunosuppressants (cyclosporine, tacrolimus, mycophenolate, corticosteroids): Reishi’s immune-stimulating beta-glucan activity may counteract immunosuppressive therapy. This is a clinically significant concern for transplant recipients and patients on immunosuppressive regimens. Severity: High. Avoid concomitant use without specialist supervision.
• Antihypertensives: Additive hypotensive effects are possible due to ACE-inhibitory activity and adenosine-mediated vasodilation. Monitor blood pressure if combining. Severity: Low-to-moderate.
• CYP450 substrates: In vitro studies suggest ganoderic acids may inhibit CYP2E1 and CYP3A4. Clinical significance is uncertain but caution is warranted with narrow therapeutic index drugs metabolized by these enzymes. Severity: Uncertain.
• Antidiabetic agents: Reishi polysaccharides (ganoderans) may lower blood glucose; additive hypoglycemia risk when combined with insulin or oral hypoglycemic agents. Severity: Low-to-moderate. Monitor blood glucose.

Side Effects

• Common: Gastrointestinal upset (nausea, bloating, diarrhea), dry mouth, mild dizziness. These effects are typically transient and dose-related.
• Uncommon: Epistaxis (nosebleeds), bloody stools (related to antiplatelet activity), skin rash or pruritus.
• Rare: Hepatotoxicity. Wanmuang et al. (2007) documented a case of fatal fulminant hepatitis in a patient consuming reishi powder for 2 months. The mechanism remains unclear and may involve contamination, idiosyncratic reaction, or concentrated triterpenoid exposure from powdered preparations. Additional isolated case reports of elevated liver enzymes have been published.

Pregnancy and Lactation

• Category: Avoid. No controlled human studies exist. Traditional texts do not specifically contraindicate reishi during pregnancy, but the absence of modern safety data warrants caution. Animal reproductive toxicity studies are limited and insufficient to establish safety.

Clinical Dosage

Dried Fruiting Body

• Standard dose: 1.5-9 g/day (per Chinese Pharmacopoeia, 2020 edition)
• Preparation: Traditionally sliced and simmered in water for 1-2 hours (decoction) to extract polysaccharides
• Note: The hard, woody (corky) texture of reishi fruiting body is unsuitable for direct consumption; extraction by decoction or processing into powder/extract is necessary

Standardized Polysaccharide Extract

• Standard dose: 1-1.5 g/day of extract standardized to polysaccharide content (typically 10-50%)
• Clinical trial dose (Ganopoly): 1,800-5,400 mg/day of polysaccharide extract in divided doses
• This is the most clinically studied dose form for immune modulation and cancer adjunctive therapy

Cracked-Wall Spore Powder

• Standard dose: 1-3 g/day of cracked (wall-broken) spore powder
• Rationale: Reishi spores possess a hard chitinous outer shell that must be mechanically cracked to release bioactive triterpenoids and lipids. Intact spores pass through the GI tract largely unabsorbed.
• Spore oil: Supercritical CO2 extract of spore lipids; typical dose 0.5-1 g/day, concentrated in triterpenoids

Dual-Extract Tincture

• Standard dose: 2-4 mL of 1:5 dual-extract tincture (hot water + ethanol extraction), two to three times daily
• This form captures both water-soluble polysaccharides and alcohol-soluble triterpenoids
• Preferred for practitioners seeking the full spectrum of reishi bioactives

Traditional Decoction (TCM Preparation)

• Method: 3-5 g of sliced dried reishi simmered in 500-750 mL water for 1-2 hours
• This preparation primarily extracts water-soluble polysaccharides and adenosine
• For triterpenoid extraction: Ethanol tincture or dual-extraction products are required

Sources

• Jin X, Ruiz Beguerie J, Sze DM, Chan GC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev. 2012;(6):CD007731
• Klupp NL, Chang D, Hawke F, et al. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev. 2015;(2):CD007259
• Gao Y, Zhou S, Jiang W, Huang M, Dai X. Effects of Ganopoly (a Ganoderma lucidum polysaccharide extract) on the immune functions in advanced-stage cancer patients. Immunol Invest. 2003;32(3):201-215
• Tang W, Gao Y, Chen G, et al. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. J Med Food. 2005;8(1):53-58
• Wachtel-Galor S, Tomlinson B, Benzie IF. Ganoderma lucidum (“Lingzhi”), a Chinese medicinal mushroom: biomarker responses in a controlled human supplementation study. Br J Nutr. 2004;91(2):263-269
• Chu TT, Benzie IF, Lam CW, Fok BS, Lee KK, Tomlinson B. Study of potential cardioprotective effects of Ganoderma lucidum (Lingzhi): results of a controlled human intervention trial. Br J Nutr. 2012;107(7):1017-1027
• Oka S, Tanaka S, Yoshida S, et al. A water-soluble extract from culture medium of Ganoderma lucidum mycelia suppresses the development of colorectal adenomas. Hiroshima J Med Sci. 2010;59(1):1-6
• Zhao H, Zhang Q, Zhao L, Huang X, Wang J, Kang X. Spore powder of Ganoderma lucidum improves cancer-related fatigue in breast cancer patients undergoing endocrine therapy: a pilot clinical trial. Evid Based Complement Alternat Med. 2012;2012:809614
• Wanmuang H, Leopairut J, Kositchaiwat C, Wananukul W, Bunyaratvej S. Fatal fulminant hepatitis associated with Ganoderma lucidum (Lingzhi) mushroom powder. J Med Assoc Thai. 2007;90(1):179-181
• Cui XY, Cui SY, Zhang J, et al. Extract of Ganoderma lucidum prolongs sleep time in rats. J Ethnopharmacol. 2012;139(3):796-800
• Chang CJ, Lin CS, Lu CC, et al. Ganoderma lucidum reduces obesity in mice by modulating the composition of the gut microbiota. Nat Commun. 2015;6:7489
• Boh B, Berovic M, Zhang J, Zhi-Bin L. Ganoderma lucidum and its pharmaceutically active compounds. Biotechnol Annu Rev. 2007;13:265-301
• Wachtel-Galor S, Yuen J, Buswell JA, Benzie IFF. Ganoderma lucidum (Lingzhi or Reishi): A Medicinal Mushroom. In: Benzie IFF, Wachtel-Galor S, editors. Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2011. Chapter 9
• Chinese Pharmacopoeia Commission. Pharmacopoeia of the People’s Republic of China. Vol 1. 2020 Edition
• Sanodiya BS, Thakur GS, Baghel RK, Prasad GB, Bisen PS. Ganoderma lucidum: a potent pharmacological macrofungus. Curr Pharm Biotechnol. 2009;10(8):717-742
• Cör D, Knez Z, Knez Hrncic M. Antitumour, antimicrobial, antioxidant and antiacetylcholinesterase effect of Ganoderma lucidum terpenoids and polysaccharides: a review. Molecules. 2018;23(3):649

Connections

• Compare with other medicinal mushroom immunomodulators: Turkey Tail (Trametes versicolor — PSK/PSP polysaccharides, strong cancer adjunctive evidence from Japanese clinical trials), Maitake (Grifola frondosa — D-fraction beta-glucans, immune activation), Chaga (Inonotus obliquus — betulinic acid, antioxidant)
• The beta-glucan/Dectin-1 immune activation pathway is shared across medicinal mushrooms, but reishi is unique in its dual polysaccharide + triterpenoid pharmacology, providing both immune-stimulating and anti-inflammatory effects within a single organism
• Compare with Lion’s Mane for a contrasting primary mechanism: Lion’s Mane acts primarily through NGF/BDNF neurotrophic stimulation (cognitive focus), while reishi acts primarily through immune modulation and adaptogenic stress response
• Cordyceps shares the adenosine-related pharmacology (cordycepin is an adenosine analog), connecting to reishi’s adenosine-mediated sedative and antiplatelet activities through overlapping receptor signaling
• Synergy with Astragalus: both are TCM qi-tonifying agents with polysaccharide-driven immune modulation; the combination is a classical TCM pairing for immune deficiency
• The traditional TCM classification of reishi as a shen tonic (calming the spirit) bridges immune and nervous system applications, connecting it to the Western adaptogen category alongside rhodiola and ashwagandha