Clinical Studies Index

🇹🇷 Bu sayfayı Türkçe oku An index of clinical studies on functional mushroom constituents tested in human subjects, ranked by level of evidence. This page presents literature information only — it does not constitute a health claim. Version 1.0 — April 2026.

Evidence Level Classification

Each constituent in this index is presented with one of the following evidence level labels:

[APPROVED] — Indication formally approved by an official health authority.
[PHASE III] — Large-scale randomized controlled trial available.
[PHASE II] — Limited human studies with efficacy and safety data.
[PHASE I / Pilot] — First-in-human studies, primarily safety-oriented.
[Preclinical] — In vitro and animal model data only; human evidence absent or minimal.

PSK / Krestin — Trametes versicolor

Evidence level: [APPROVED — Japan]

Polysaccharide-K (PSK, trade name Krestin) is a protein-bound polysaccharide isolated from Trametes versicolor. It received approval in 1977 from Japan's Ministry of Health, Labour and Welfare as an adjuvant therapy for gastric, colorectal, and non-small cell lung cancers. Its use alongside chemotherapy is covered under the Japanese national health insurance system.

Reference studies: Tsukagoshi et al. (1984) Cancer Treatment Reviews; Oba et al. (2007) meta-analysis, Cancer Immunology Immunotherapy.

Application: Employed exclusively as an oncological adjuvant, prescribed by physicians in Japan. It is not directly equivalent to Turkey Tail powders sold as dietary supplements.

Lentinan — Lentinula edodes

Evidence level: [APPROVED — Japan]

Lentinan is a β-1,3-glucan polysaccharide isolated from Shiitake mushroom. Since 1985, it has held approval in Japan as an intravenous injectable formulation for adjuvant chemotherapy in advanced gastric cancer.

Reference studies: Chihara (1969) Cancer Research; Hazama et al. (2009) Hepato-Gastroenterology, investigating an oral superfine dispersed lentinan form.

Application: Shiitake powder in oral food form is pharmacokinetically distinct from injectable lentinan. The clinical approval applies specifically to the injectable formulation.

AHCC (Active Hexose Correlated Compound) — Mushroom Mycelial Fermentation Product

Evidence level: [PHASE II — multiple studies]

AHCC is an α-glucan-rich mixture produced through controlled fermentation of selected Basidiomycetes mycelia. It has been the subject of more than 100 human studies. The most notable investigations concern its use as an adjuvant in hepatocellular carcinoma (Matsui et al., 2002) and its role in HPV clearance (Smith et al., 2019, University of Texas MD Anderson Cancer Center).

Reference studies: Matsui et al. (2002) Journal of Hepatology; Smith et al. (2019) Journal of Alternative and Complementary Medicine.

Application: AHCC is classified as a functional food in Japan. Its production requires a proprietary manufacturing process.

Hericium erinaceus — Cognitive Function

Evidence level: [PHASE II — small sample sizes]

Mori et al. (2009, Phytotherapy Research): A 16-week double-blind, placebo-controlled trial in 30 Japanese subjects aged 50–80 with mild cognitive impairment. The Lion's Mane group demonstrated statistically significant improvement in HDS-R (Revised Hasegawa Dementia Scale) scores. However, the sample size was small, and the effect disappeared four weeks after discontinuation.

Saitsu et al. (2019, Biomedical Research): A 12-week placebo-controlled trial in 31 Japanese adults, reporting improvements on cognitive function tests.

Commentary: Promising preliminary data exist, but Phase III-quality studies are not yet available. No specific indication approval exists for dementia or Alzheimer's disease.

Cordyceps sinensis / militaris — Exercise Performance

Evidence level: [PHASE II — mixed results]

Chen et al. (2010, Journal of Alternative and Complementary Medicine): Investigated the effect of a Cs-4 formulation on VO₂max in 20 healthy older adults. Increased exercise tolerance was reported.

Hirsch et al. (2017, Journal of Dietary Supplements): A 3-week study in 28 university-aged athletes found no difference in maximal oxygen uptake.

Commentary: Results are mixed. Differences in population (older adults versus young athletes), dosage, and study duration contribute to methodological heterogeneity.

Ganoderma lucidum (Reishi) — Quality of Life

Evidence level: [PHASE II — assessed by Cochrane review]

Jin et al. (2016, Cochrane Database of Systematic Reviews): A meta-analysis of five randomized controlled trials. Quality-of-life scores (QLQ-C30) improved in the G. lucidum group among cancer patients, but evidence for an antitumor effect was deemed insufficient. Additional research on sleep and immune parameters was recommended.

Grifola frondosa (Maitake) D-Fraction — Immunity

Evidence level: [PHASE I / II]

Deng et al. (2009, Journal of the Society for Integrative Oncology): A Phase I/II study in 34 postmenopausal breast cancer patients. The D-fraction was reported to produce dose-dependent changes in immune parameters.

Ergothioneine — Antioxidant and Metabolic Role

Evidence level: [Preclinical + observational]

Interventional human studies are limited. Observational research (Smith et al., 2020, Heart) has reported correlations between low plasma ergothioneine levels and cardiovascular and neurodegenerative risk markers. Causality has not been established.

Important Methodological Notes

Form differences: The majority of clinical studies employ standardized extracts or specific isolated compounds. Generic mushroom powders available on the market are not pharmacokinetically equivalent to these formulations.
Population differences: Study results obtained in Japanese and Chinese populations may not translate directly to other populations due to genetic and microbiome variations.
Publication bias: In the functional mushroom field, studies with positive outcomes have a higher probability of being published. Systematic reviews partially compensate for this bias.

Legal Framework: Legal status in Turkey and internationally · Editorial Method: Source hierarchy and evidence level labeling · Reference List: Bibliography

Version 1.0 — April 2026