Supplement analysis backed by scientific evidence · PT

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Limited evidenceImmunity

Maitake

Maitake (Grifola frondosa) has the most interesting small trials of the culinary medicinal mushrooms — a phase I/II study showing dose-dependent immune changes in breast cancer patients, and a small ovulation-induction trial in PCOS — but nothing has been replicated at scale. Promising, unproven.

What the science says

  • Immune modulation is dose-dependent but bidirectional Limited evidence

    A phase I/II dose-escalation trial in 34 postmenopausal breast cancer survivors gave oral maitake polysaccharide extract for 3 weeks and found statistically significant changes in ex vivo cytokine production that were non-monotonic: some immune parameters increased at intermediate doses while others were suppressed at the highest doses. The authors explicitly warned that more is not better and that clinical significance is unknown.

  • Ovulation induction in PCOS Limited evidence

    An open randomized trial in 80 women with PCOS reported ovulation in 77% of cycles on maitake SX-fraction versus 94% on clomiphene citrate, and 6 of 8 clomiphene non-responders ovulated when maitake was added. This was unblinded, single-centre, and never replicated; it is a signal worth studying, not a reason to substitute maitake for fertility treatment.

  • Blood glucose and insulin sensitivity Limited evidence

    The 'SX-fraction' glucose claim rests on rodent work and a handful of small uncontrolled human series; there is no adequately powered placebo-controlled trial showing improved HbA1c or fasting glucose in humans. Do not use it in place of established glycemic therapy.

  • Myelodysplastic syndrome and blood counts Limited evidence

    A phase II study of maitake extract in 21 patients with myelodysplastic syndrome found enhanced neutrophil and monocyte function ex vivo, but no meaningful change in blood counts or transfusion requirements. Functional assay changes without hematologic improvement is the recurring pattern in maitake research.

Dosage & safety

Studied doseTrials used purified fractions, not the whole mushroom: the breast cancer study escalated from 0.1 to 5 mg/kg twice daily of polysaccharide extract; the PCOS study used maitake SX-fraction at roughly 18 mg three times daily. Commercial capsules typically supply 500-1,200 mg/day of unstandardized extract, which does not map onto any studied fraction. Culinary intake is 50-100 g fresh mushroom.
SafetyWell tolerated in short trials; reported effects are mild GI upset and, occasionally, low blood pressure. Two real interaction concerns: maitake may add to the glucose-lowering effect of insulin and oral hypoglycemics (monitor if diabetic), and case-level evidence suggests potentiation of warfarin with raised INR — avoid or monitor closely on anticoagulants. Given the bidirectional immune effects seen in trials, use caution in autoimmune disease and in transplant recipients, and clear it with an oncologist before combining with chemotherapy or immunotherapy. Long-term safety beyond a few months is uncharacterized. Not banned in sport.

Scientific references

Where to buy

Vitacost, Root2, Maitake Mushroom Extract, 500 mg, 100 Capsules

View on iHerb

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