Mushroom
    Moderate Evidence

    Turkey Tail

    Trametes versicolor

    TL;DR

    Turkey tail is unusual among medicinal mushrooms: its standardized extracts PSK and PSP were used as licensed adjuncts to cancer chemotherapy in Japan and China, with survival meta-analyses in gastric and colorectal cancer. Ordinary consumer mushroom powders are not the same product and have no comparable evidence.

    Ideal For

    • People seeking evidence-backed mushroom immune support alongside medical care

    Avoid If

    • Organ transplant immunosuppression
    • Autoimmune disease on immune-modulating therapy

    Frequently Asked Questions

    Overview

    Trametes versicolor yields two standardized protein-bound polysaccharides: PSK (krestin, Japan) and PSP (China). Meta-analyses of adjuvant PSK alongside chemotherapy in gastric and colorectal cancer report modest but statistically significant survival gains, and small US phase I work showed immune cell recovery after breast cancer radiotherapy. That evidence is specific to pharmaceutical-grade, hot-water polysaccharide extracts at gram-level doses, taken alongside conventional treatment. Most retail turkey tail is mycelium grown on grain, where beta-glucan content is diluted by starch and the polysaccharide profile is unverified.

    How It Works

    • Beta-glucans engage dectin-1 and TLR receptors on innate immune cells
    • Increases NK cell and cytotoxic T-lymphocyte activity
    • Restores lymphocyte counts after chemotherapy or radiotherapy

    Quick Facts

    • PSK has been a licensed oncology adjunct in Japan since 1977
    • Trial doses are 3 g/day of standardized extract, not 500 mg capsules
    • Grain-grown mycelium products are largely starch

    Benefits & Outcomes

    Immune Function

    Immune
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    The pharmaceutical extracts earn a genuine yes; consumer-grade mycelium products have essentially no evidence behind them.

    Macrophage Function

    Immune
    Likely effective
    Moderate Evidence

    Turkey tail polysaccharides (PSK/PSP) are approved as cancer-treatment adjuncts in Japan and prime macrophage and NK activity in human studies.

    Natural Killer Cell Activity

    Immune
    Insufficient evidence
    Preliminary
    Effectiveness 3/5

    Immune-marker changes are documented; general-population benefit is unproven.

    Health Concerns Addressed

    No linked health concerns yet.

    Supporting Research
    5 studies

    Trametes versicolor mushroom immune therapy in breast cancer

    Score: 4/10
    2008
    systematic_review

    Standish LJ, Wenner CA, Sweet ES

    PSK enhances natural killer and T cell activity in laboratory studies and has survival data from Japanese adjuvant trials

    View source

    Efficacy of adjuvant immunochemotherapy with polysaccharide K for patients with curatively resected colorectal cancer: a meta-analysis of centrally randomized controlled clinical trials

    Score: 7/10
    2006
    meta_analysis
    n=1094

    Sakamoto J, Morita S, Oba K

    Adjuvant PSK improved overall and disease-free survival after curative colorectal cancer resection

    View source

    Can polysaccharide K improve therapeutic efficacy and safety in gastrointestinal cancer? A systematic review and network meta-analysis

    Score: 6/10
    2017
    meta_analysis

    Ma Y, Wu X, Yu J

    PSK added to chemotherapy improved survival outcomes in gastrointestinal cancer with acceptable safety

    View source

    Phase 1 clinical trial of Trametes versicolor in women with breast cancer

    Score: 4/10
    2012
    rct
    n=11

    Torkelson CJ, Sweet E, Martzen MR

    Trametes versicolor was well tolerated up to 9 g/day with dose-dependent recovery of lymphocyte and natural killer cell counts

    View source

    TLR2 agonist PSK activates human NK cells and enhances the antitumor effect of HER2-targeted monoclonal antibody therapy

    Score: 4/10
    2011
    observational

    Lu H, Yang Y, Gad E

    PSK activated natural killer cells via TLR2 and enhanced antibody-mediated antitumor effects

    View source

    Safety Information

    Potential Side Effects

    Mild digestive upset, nausea and darkened stool. Rare skin reactions.

    Contraindications

    Discuss with oncology team before use during active cancer treatment; theoretical interaction with immunosuppressants.

    Drug Interactions

    • Immunosuppressants

    Pregnancy & Breastfeeding

    Pregnancy: insufficient_data

    Breastfeeding: insufficient_data

    Dosage Guidelines

    Dosage Used in Studies

    1000-3000 mg extract

    Best Time to Take

    With or without food

    Best Form

    Hot-water fruiting-body extract standardized to beta-glucans

    Bioavailability

    Polysaccharides are not absorbed intact; they act on gut-associated immune tissue and via microbiome fermentation.

    Forms Compared

    The form used in oncology trials, 3 g/day

    Reasonable consumer proxy; check beta-glucan percentage

    High starch, low beta-glucan; avoid

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.