Ganoderma tsugae (Hemlock Reishi)
A North American relative of reishi that grows on eastern hemlock — popular among herbalists in the US and Canada as 'hemlock reishi,' but with a much thinner body of scientific research.
Number of studies
2
Safety
Moderate
Time to effects
No data from human studies.
Monthly cost
ok. 70-140 zł/miesiąc
Price in Poland
80-160 zł za 50-60 ml rzemieślniczej nalewki lub 60-100 zł za 100 g suszonych owocników
Who it's for
Produkt niszowy, dostępny niemal wyłącznie od małych, rzemieślniczych producentów w Ameryce Północnej.
Indicative prices for the Polish market — we don't point to specific retailers; the real price depends on the manufacturer, form and place of purchase.
Table of contents
TL;DR
A North American relative of reishi that grows on eastern hemlock — popular among herbalists in the US and Canada as 'hemlock reishi,' but with a much thinner body of scientific research.
- →A triterpene extract inhibited the release of histamine and Th2 cytokines in an in vitro study
- →In a study on chemotherapy-resistant lung cancer cells, the extract induced apoptosis, enhancing doxorubicin's action
- →Contains triterpenes and polysaccharides with documented in vitro antioxidant activity
| Latin name | Ganoderma tsugae |
|---|---|
| Family | Ganodermataceae |
| Active substances | Triterpenes (triterpene fraction), beta-glucan polysaccharides |
| Form | Dual-extract tincture or dried, wild-foraged fruiting body |
| Evidence level | Preliminary — 2 in vitro studies, no animal or human studies |
| Interactions | Anticoagulant/antiplatelet drugs (theoretical), chemotherapy — in vitro data suggesting an interaction with doxorubicin |
| Status | A niche, artisanal product available mainly in North America |
Understand
Overview
Ganoderma tsugae, known as hemlock reishi, is a species closely related to the reishi mushroom (Ganoderma lucidum), colonizing almost exclusively coniferous wood, primarily eastern hemlock. Like reishi, it forms a glossy cap, which has led herbalists in the US and Canada to use it as a local equivalent of the Asian mushroom.
Despite its chemical similarity to reishi, dedicated research on G. tsugae itself is much thinner. Treating G. tsugae as a 'substitute' for reishi with an identically documented effect would be unjustified.
Who can this realistically help? Practically only enthusiasts of forest fungi and North American herbalism who are knowingly looking for a wild, regional equivalent of reishi and accept that the evidence is limited to two in vitro studies. This isn't an option for people counting on documented antiallergic effects or chemotherapy support in humans. Because of a theoretical interaction with doxorubicin and anticoagulant drugs, this species in particular isn't recommended for people undergoing chemotherapy without medical consultation.
Where it's found
Ganoderma tsugae occurs almost exclusively in North America, colonizing dead and dying coniferous wood — primarily eastern hemlock. Most commonly found in the eastern forests of the US and Canada.
History of use
Unlike reishi, Ganoderma tsugae has no documented centuries-old tradition of use in Chinese or Japanese medicine — it's a North American species. For several decades it has been foraged and processed by Western herbalists as a local, wild-growing equivalent of the Asian reishi.
Mechanism of action
In vitro studies separated a triterpene fraction and a polysaccharide fraction — the triterpene fraction inhibited the release of histamine and Th2 cytokines from mast cells. In a study on lung cancer cell lines, the extract inhibited proliferation via cell-cycle arrest, enhancing the action of doxorubicin.
As with other Ganoderma species, G. tsugae's activity is most likely tied to lanostane triterpenes structurally related to the ganoderic acids described in reishi, as well as beta-glucan-type polysaccharides. The S-phase cell-cycle arrest observed in lung cancer cells is a complementary mechanism, not a replacement for doxorubicin's action — hence the synergy described in the study, rather than standalone cytotoxicity of the extract.
Fraction separation
A triterpene fraction and a polysaccharide fraction were separated from the fruiting-body extract for in vitro testing.
Inhibition of mast cell degranulation
The triterpene fraction inhibited the release of histamine and Th2 cytokines from activated mast cells.
S-phase cell-cycle arrest
In doxorubicin-resistant lung cancer cells, the extract arrested the cell cycle in the S phase.
Induction of apoptosis and synergy with chemotherapy
Cell-cycle arrest led to apoptosis of cancer cells, enhancing doxorubicin's effect.
Evidence: early-stage — based on 2 studies in this database.
Benefits
Common myths
MythGanoderma tsugae is simply 'American reishi' with an identically documented effect.
FactIt's a distinct species with a different habitat and a much thinner research base.
Forms & variants
Ganoderma tsugae (Hemlock Reishi) comes in several forms that differ in bioavailability and use case — the form you pick genuinely matters for how effective the supplementation is.
Dried, wild-foraged fruiting body
Foraged mainly in the forests of eastern North America.
Best for: Foraging enthusiasts and traditional herbalism
Practice
Frequently asked questions
Mainly by habitat — G. tsugae grows on coniferous wood in North America, and the quantity and quality of dedicated research is much smaller.
Dosage & timing
Typical dose
No dosing established in clinical studies. Small producers suggest doses analogous to reishi
Form
Dual-extract tincture or dried, wild-foraged fruiting body
Dosing is informational and reflects the ranges used in the cited studies — it does not replace consulting a doctor or pharmacist.
Best times to take it
- With a meal containing fat
What to combine with
Good combinations
Reishi (Ganoderma lucidum) — Closely related species with a similar chemical profile
Lion's Mane — Popular in niche mushroom 'stacks'
Safety
Side effects & contraindications
Possible side effects
No dedicated safety studies in humans
Theoretically a similar tolerance profile to reishi
Contraindications
Mushroom allergy
Liver disease — caution
Pregnancy and breastfeeding — no data
Interactions
Anticoagulant/antiplatelet drugs — theoretical risk
Chemotherapy — in vitro data suggesting an interaction with doxorubicin
Is it worth taking?
Who it's for
- Enthusiasts of forest fungi and North American herbalism
Not for
- Mushroom allergy
- Liver disease — caution
- Pregnancy and breastfeeding — no data
Evidence
Worth knowing
The English name 'hemlock varnish shelf' refers to its lacquered cap and its preferred host — eastern hemlock.
Studies
The triterpene fraction significantly inhibited the release of histamine and Th2 cytokines from activated mast cells in vitro.
Chen ML, Hsieh CC, Chiang BL, Lin BF, Evidence-Based Complementary and Alternative Medicine, 2015
Ganoderma tsugae Induces S Phase Arrest and Apoptosis in Doxorubicin-Resistant Lung Adenocarcinoma Cells
Research hypothesisYu YH, Kuo HP, Hsieh HH, Li JW, Hsu WH, et al. · Evidence-Based Complementary and Alternative Medicine · 2012
The extract inhibited the proliferation of doxorubicin-resistant lung cancer cells through cell-cycle arrest and apoptosis induction.
View studyTriterpenoids and Polysaccharide Fractions of Ganoderma tsugae Exert Different Effects on Antiallergic Activities
Research hypothesisChen ML, Hsieh CC, Chiang BL, Lin BF · Evidence-Based Complementary and Alternative Medicine · 2015
The triterpene fraction significantly inhibited the release of histamine and Th2 cytokines from activated mast cells in vitro.
View studySources & bibliography
Citations are illustrative for this demo version and require full bibliographic verification by the editorial team before production publication.
Compare with similar entries
About the authors of this entry
Author
Michał NowakClinical Dietitian
Michał specializes in metabolic nutrition, intermittent fasting and sports supplementation.
61 publications on this site
Medical review
dr Anna KowalczykEditor-in-Chief, Molecular Biology
Anna oversees the editorial process and scientific review of every publication in the knowledge base. She previously researched autophagy and mitochondrial biology.
50 publications on this site
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Comments (2)
- KW
Kasia W. 2 weeks ago
Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.
- MT
Marek T. a month ago
Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.