Supplement analysis backed by scientific evidence · PT

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Limited evidenceImmunity

Reishi Mushroom

Two Cochrane reviews looked hard at reishi and found little: no demonstrated survival benefit in cancer and no benefit at all for cardiovascular risk factors. Extremely popular, and the human data are poor.

What the science says

  • Adjunct in cancer treatment Limited evidence

    A Cochrane review found 5 eligible RCTs. Patients given Ganoderma lucidum alongside chemotherapy or radiotherapy were more likely to show a tumour response (RR 1.50, 95% CI 0.90-2.51), but the confidence interval crosses no effect, no trial recorded long-term survival, and the reviewers described the methodological quality as generally unsatisfying. Cochrane did not recommend it as first-line treatment.

  • Cardiovascular risk factors and glycemia Limited evidence

    A separate Cochrane review of 5 trials in 398 participants — with the analysable trials giving 1.4-3 g/day for 12-16 weeks to people with type 2 diabetes — found no significant effect on HbA1c (WMD -0.10%), total cholesterol, LDL, BMI, blood pressure, or triglycerides. The authors' conclusion was explicit: the evidence does not support its use for cardiovascular risk factors.

  • Sleep, stress, and adaptogenic effects Limited evidence

    Reishi is widely marketed for calm and sleep on the strength of rodent studies showing sedative and sleep-latency effects. There is no adequate human randomized trial for sleep or stress outcomes.

Dosage & safety

Studied doseTrials used 1.4-3 g/day of extract, or the equivalent of roughly 1.5-9 g/day of dried mushroom, for 12-16 weeks. No dose has been established as effective for any indication. Extract-to-raw ratios and beta-glucan content vary hugely between products.
SafetyAdverse effects are usually mild — dizziness, dry mouth, nosebleed, GI upset — but in the Cochrane cardiovascular review participants on reishi were 1.67 times more likely than placebo to report an adverse event (none serious). Case reports link powdered reishi to hepatotoxicity, including a fatal case of fulminant hepatitis; the powdered form appears more implicated than hot-water extracts. Reishi has antiplatelet activity — caution with anticoagulants, antiplatelets, and before surgery. Avoid in pregnancy, breastfeeding, and alongside immunosuppressants.

Scientific references

Where to buy

Swanson Vitamins, Reishi Mushroom Extract, Standardized, 500 mg, 90 Capsules

View on iHerb

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