Turkey Tail Mushroom

Trametes versicolor
Evidence Level
Moderate
2 Clinical Trials
4 Documented Benefits
3/5 Evidence Score

Turkey Tail is a polypore mushroom with a long history of use in Traditional Chinese Medicine and is one of the most well-researched medicinal mushrooms for immune support. Its primary bioactive compounds — PSK and PSP — have been studied extensively in cancer care as adjunct immunotherapy.

Studied Dose 1–3 g/day PSK extract; 2–9 g/day whole mushroom powder
Active Compound Polysaccharide-K (PSK / Krestin) and Polysaccharopeptide (PSP) — protein-bound beta-glucans

Immune system activation

PSK and PSP activate dendritic cells, macrophages, and NK cells via Toll-like receptor and Dectin-1 signaling, enhancing both innate and adaptive immune responses.

Adjunct cancer support

PSK is an approved cancer adjunct therapy in Japan, used alongside conventional chemotherapy for gastric, colorectal, and lung cancers. Trials show improved survival rates and reduced immunosuppression from chemotherapy.

Gut microbiome support

Turkey tail acts as a prebiotic, selectively feeding Bifidobacterium and Lactobacillus species. Clinical study showed significant increases in beneficial bacteria and reduction in Clostridium after supplementation.

Antioxidant protection

Rich in phenolic compounds including quercetin and baicalein that scavenge free radicals and reduce oxidative stress markers in both healthy and immunocompromised individuals.

1

TLR-2 and Dectin-1 activation

Beta-glucans in PSK and PSP bind pattern recognition receptors on macrophages and dendritic cells, triggering NF-κB activation and cytokine production that primes adaptive immune responses.

2

NK and T-cell augmentation

Turkey tail polysaccharides increase NK cell cytotoxicity and CD8+ T-cell activity, enhancing immune surveillance for abnormal or virus-infected cells.

3

Prebiotic fermentation

Polysaccharides from turkey tail are fermented by colonic microbiota, producing short-chain fatty acids and selectively feeding beneficial bacterial species, improving gut microbiome composition.

1
Turkey Tail Mushroom and Gut Microbiome in Healthy Adults
PubMed

Open-label clinical study of turkey tail powder (2.4–4.8 g/day) for 8 weeks in healthy adults.

24 healthy adults. 8-week supplementation.

Dose-dependent increases in Bifidobacterium and Lactobacillus. Significant decreases in Clostridium and Staphylococcus. Improved microbiome diversity scores.

2
PSK as Adjuvant Immunotherapy for Gastric Cancer
PubMed

Meta-analysis of RCTs using PSK alongside chemotherapy in gastric cancer patients in Japan.

Multiple trials, hundreds of patients.

PSK supplementation significantly improved 5-year survival rates and reduced immunosuppression from chemotherapy. Now standard-of-care adjuvant in Japan for GI cancers.

Common Potential side effects

Very well tolerated; occasional mild GI discomfort
Rare allergic reactions in mushroom-sensitive individuals
Dark stools possible — benign pigment effect of mushroom polyphenols

Important Drug interactions

Immunosuppressants — may reduce drug efficacy by stimulating immune activity
Chemotherapy — PSK is specifically studied as an adjunct; generally beneficial but consult oncologist
Anticoagulants — mild platelet effects possible; monitor