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Reishi Side Effects & Safety

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Safe with Caution

Potential Side Effects

  • Mild digestive upset (nausea, bloating) in some users
  • Dry mouth and throat
  • Dizziness or headache (uncommon)
  • Rare: liver toxicity reported with concentrated reishi powders (case reports)
  • Nosebleeds or blood-thinning effects at high doses

Drug & Supplement Interactions

  • May enhance effects of anticoagulant/antiplatelet medications (reishi inhibits platelet aggregation)
  • May lower blood pressure — caution with antihypertensive medications
  • May interact with immunosuppressant drugs (stimulates immune function)
  • May lower blood sugar — monitor with diabetes medications
  • Discontinue 2 weeks before surgery due to blood-thinning effects

Maximum Dose

Do not exceed: 5.4g extract daily (highest dose used in clinical trials)

Full Reishi Guide

References

  1. Meta-analysisJin X, Ruiz Beguerie J, Sze DM, Chan GC (2016). Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database of Systematic Reviews. DOI PubMed
  2. Meta-analysisJin X, Ruiz Beguerie J, Sze DM, Chan GC (2012). Ganoderma lucidum (Reishi mushroom) for cancer treatment.. The Cochrane database of systematic reviews. DOI PubMed
  3. ReviewCizmarikova M (2017). The Efficacy and Toxicity of Using the Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), and Its Products in Chemotherapy (Review).. International journal of medicinal mushrooms. DOI PubMed
  4. RCTMitra S, Mitra M, Nandi DK, Saha M, et al. (2024). Efficacy of Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) Supplementation on Psychological Stress and Selective Fitness Profile Parameters in Female College Students in West Bengal, India.. International journal of medicinal mushrooms. DOI PubMed
  5. Meta-analysisNarayanan S, de Mores AR, Cohen L, Anwar MM, et al. (2023). Medicinal Mushroom Supplements in Cancer: A Systematic Review of Clinical Studies.. Current oncology reports. DOI PubMed
  6. RCTWightman E, Khan J, Smith E, Rolfe V, et al. (2023). Chronic supplementation of a multi-ingredient herbal supplement increases speed of cognitive task performance alongside changes in the urinary metabolism of dopamine and the gut microbiome in cognitively intact older adults experiencing subjective memory decline: a randomized, placebo controlled, parallel groups investigation.. Frontiers in nutrition. DOI PubMed
  7. Azizi M, Tavana M, Farsi M, Oroojalian F (2012). Yield performance of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.) P. Karst. (higher Basidiomycetes), using different waste materials as substrates.. International journal of medicinal mushrooms. DOI PubMed