Reishi
Reishi (Ganoderma lingzhi, formerly Ganoderma lucidum in much commercial labelling) is a polypore mushroom with thousands of years of use in East Asian medicine. It is supplied in supplements as fruiting body, spore powder, or chemically extracted polysaccharide / triterpene fractions. The published human evidence is limited and EFSA has not authorised any UK health claim for it.
Camden Medicals editorial · Last reviewed 27 April 2026 · Next review April 2027
- Cross-checked against
- NHS
- NICE
- BNF
- EFSA
- FSA
Camden's editorial team independently graded each health claim below on the strength of the published evidence — see the grade beside every condition.
- Class
- Mushroom
- Typical daily dose
- Most published human trials use 1.4 to 5.4 g/day of Ganoderma extract for 4 weeks to several months. UK supplements typically deliver 500-2,000 mg of mushroom equivalent per serving.
- Top use evidence
- Limited
On this page
What it is
Reishi is a polypore mushroom in the family Ganodermataceae. Modern molecular taxonomy (Cao et al. 2012) split the historical "Ganoderma lucidum" complex into multiple species; the East Asian cultivated species used in Chinese medicine and most commercial supplements is now formally Ganoderma lingzhi. Much commercial labelling still uses "G. lucidum" — a holdover from the older taxonomy.
Three commercial supplement formats appear in UK shops: fruiting-body extract powder; mycelium-on-grain powder; and spore powder (cracked or "broken-cell-wall"), which has a different triterpene profile from fruiting body.
Two compound classes carry most of the mechanistic discussion in the literature: polysaccharides (β-glucans of various structures, studied for innate immune effects in cell and animal models) and triterpenoid compounds (ganoderic acids, studied for hepatic and anti-inflammatory effects in animal models).
At a glance
- Polypore mushroom; thousands of years of traditional use in East Asia (lingzhi / 灵芝).
- No GB-authorised health claim. EFSA evaluation of botanical health claims has been on hold since 2010.
- Most human trials are small; some limited evidence for adjunctive use during cancer treatment, under specialist supervision only.
- Substrate matters: fruit body extract is what most studies used; mycelium-on-grain powder is largely grain by mass.
- Caution with anticoagulants — animal data on platelet effects, weak human signal. Talk to your pharmacist.
What people use it for
People exploring traditional botanicals
Reishi has a long traditional-use history in East Asian medicine. The traditional-use frame is permissible in UK marketing; specific health claims are not authorised.
Some evidenceLimitedCancer patients receiving conventional treatment, with specialist supervision
A 2016 Cochrane review (Jin et al., CD007731) of Ganoderma lucidum for cancer treatment found low-quality evidence that adjunctive use during chemotherapy or radiotherapy may improve immune function markers and quality of life — evidence for tumour response is insufficient. Reishi is NOT a treatment for cancer; it has been studied as adjunctive therapy under specialist oversight only. [1]
Some evidenceLimitedPeople with sleep difficulties
Folk and traditional use of reishi for sleep is widely cited; published human RCT evidence is sparse. NHS recommends sleep hygiene + GP review for persistent sleep problems before turning to supplements.
Popular, not provenInsufficient
How it works
In cell-culture and animal models, reishi polysaccharides activate macrophage and natural-killer cell signalling pathways, and triterpenoid fractions show effects on inflammatory cytokines and on cancer cell lines. Translation to human clinical outcomes is limited; few human trials have measured immune cell function with methodologically-strong outcomes, and where measured, effects are small.
Common myths
Myth"Reishi cures cancer"
RealityIt does not. The Cochrane review of adjunctive use in cancer found evidence for tumour response is insufficient. Reishi has been studied alongside conventional cancer therapy under specialist supervision, not as a replacement. Marketing reishi for a cancer indication crosses into MHRA medicines-borderline territory and is not appropriate. [1]
Myth"Reishi spore powder is universally "superior potency" than fruiting body"
RealityThe two have different triterpene and polysaccharide profiles. Most published human trials used fruiting-body extracts. The "superior potency" framing depends on which compound is the marker — there is no consensus that one form is universally superior.
Myth"Reishi is a "natural alternative" to immunosuppressants or anti-inflammatories"
RealityIt is not. Reishi has shown immune-modulating effects in cell and animal models, but it is not a substitute for prescribed treatments for autoimmune disease, transplant medicine, or any condition where immunosuppression is the goal.
Common online questions
Synthesised from the questions UK shoppers most often ask online about Reishi. Each answer is editorial and links to its evidence in the Sources list below.
Can I take reishi during chemotherapy?
Only with your oncology team's explicit knowledge and approval. Some cancer-care pathways permit adjunctive reishi (Cochrane CD007731.pub3 reviewed it favourably for immune-function and quality-of-life markers), but interactions with specific chemotherapy regimens, anticoagulants, and other cancer-related medications need clinical assessment. Do not self-add any supplement during chemotherapy without telling your team. [1]
Will reishi help me sleep?
Folk and traditional history say yes; published human RCT evidence is sparse. If sleep is a persistent problem, talk to your GP about sleep-hygiene practices and evidence-based options first.
Fruiting body vs spore powder vs mycelium — what should I look for?
Fruiting body extract is what most published human trials used. Spore powder (cracked-cell-wall) is a different chemical profile. Mycelium-on-grain powder is largely grain by mass; the bioactives the literature studied are present at much lower concentrations. Look for a stated beta-glucan percentage and a substrate declaration on the label.
I take warfarin — is reishi safe?
Animal data has shown platelet-aggregation effects, and a small number of human case reports describe interactions with anticoagulants. Talk to your prescribing clinician or pharmacist before adding reishi to any regimen that includes warfarin, apixaban, rivaroxaban, or another anticoagulant.
Is reishi safe in pregnancy?
There is not enough safety data on reishi supplementation in pregnancy. Eating mushrooms as food is a different exposure from concentrated extracts. Talk to your midwife or GP first.
🔬 Camden’s evidence review
The research Camden reviewed, graded on its strength. This is our own appraisal — it sits beneath the official guidance above, never above it.
Adjunctive use in cancer treatment
LimitedEvidencelimitedCochrane review (Jin et al., CD007731.pub3, 2016) found low-quality evidence that Ganoderma lucidum given alongside chemotherapy or radiotherapy may stimulate host immune function and improve some quality-of-life measures, but evidence for tumour response is insufficient. Use only under oncology specialist supervision. [1]
Cardiovascular risk factors in type 2 diabetes
InsufficientEvidenceinsufficientA 2015 Cochrane review (Klupp et al., CD007259.pub2) of Ganoderma lucidum for cardiovascular risk factors in type 2 diabetes found no clinically meaningful benefit and noted methodological limitations across the small number of available trials. [2]
Fatigue, sleep, anxiety in healthy adults
InsufficientEvidenceinsufficientAnecdotal and traditional-use claims; no convincing RCT evidence in healthy adults.
Safety
Reishi is generally well tolerated in published trials at typical doses, but long-term safety data in healthy adults is limited and EFSA has not authorised any UK health claim. Anticoagulant users and pregnant women should talk to a clinician first.
Talk to your pharmacist or GP first if you:
- You take an anticoagulant (warfarin, apixaban, rivaroxaban, etc.).
- You are receiving cancer treatment — only use with explicit oncology-team approval.
- You take immunosuppressants for autoimmune disease or after a transplant.
- You are pregnant, breastfeeding, or thinking of becoming pregnant.
- You have a known mushroom allergy.
- You have liver disease — rare hepatotoxicity case reports exist.
Common side effects: Mild digestive complaints in the first few days. Rare in published trials.
Pregnancy and breastfeeding
Insufficient safety data on reishi supplementation in pregnancy. Talk to your midwife or GP.
Same framing.
Talk to your GP, midwife, or pharmacist before starting any supplement during pregnancy or breastfeeding.
More clinical detail (for clinicians and informed readers)
Contraindications
- Known mushroom allergy.
Drug interactions
- Anticoagulants — animal data on platelet aggregation; isolated human case reports of warfarin INR fluctuation. Talk to your prescriber.
- Immunosuppressants — theoretical immune-modulation; clinical advice indicated.
- Chemotherapy regimens — only use with explicit oncology-team approval.
This is not an exhaustive list. Always tell your prescriber and pharmacist about every supplement you take.
Common side effects
- Mild digestive complaints reported occasionally in trials.
Rare side effects
- Rare case reports of hepatotoxicity (raised liver enzymes); causality not always clear.
- Allergic reactions in mushroom-allergic individuals.
How to take it
- Typical supplemental range
- Most published human trials use 1.4 to 5.4 g/day of Ganoderma extract for 4 weeks to several months. UK supplements typically deliver 500-2,000 mg of mushroom equivalent per serving.
- Timing
- No specific timing requirement.
How to spot quality
Look for
- Substrate declared: fruit body, spore powder, or mycelium-on-grain.
- Beta-glucan percentage stated specifically (not just "polysaccharides").
- Extract ratio AND mushroom-equivalent dose calculated.
- GMP-certified manufacture; ideally third-party heavy-metals testing.
Red flags
- Substrate not declared.
- Cancer-treatment claims or immune-boost marketing claims.
- "30% polysaccharides" presented as a quality marker.
Commonly combined with
Other ingredients that share a biological pathway, cofactor relationship, or evidence-backed protocol with this one. Mechanisms below cite primary physiology — not folk pairing. Doses are literature ranges, not recommendations. Talk to your pharmacist or GP before changing your stack, especially if you take prescription medication.
Lion's Mane
Limited evidenceReishi and Lion's Mane target different systems (Reishi = immunomodulation, Lion's Mane = neurotrophic) and are commonly stacked for that reason.
Lion's Mane (Hericium erinaceus) contains hericenones and erinacines that have been shown in vitro and in animal models to stimulate nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) expression — the mechanistic basis for its cognitive and mood claims. Reishi (Ganoderma lucidum) contains beta-D-glucan polysaccharides that interact with toll-like receptors on macrophages, dendritic cells, NK cells and lymphocytes, with measurable in vitro and animal-model immunomodulatory effects. The two mushrooms target different physiology — neurotrophic vs immune — and the combination rationale is system-coverage rather than direct synergy. Clinical evidence in humans for either mushroom alone is limited; combination evidence is essentially absent.
Evidence: Chong 2019 (Int J Mol Sci 21:163) reviewed Lion's Mane mechanism for depressive disorder, summarising NGF/BDNF pathway evidence. Samberkar 2015 (Int J Med Mushrooms 17:1047) demonstrated Lion's Mane neurite outgrowth in vitro. Xu 2011 (Am J Chin Med 39:15) reviewed Ganoderma lucidum polysaccharide immunomodulation evidence. No published RCTs evaluate the Lion's Mane + Reishi combination in humans; the combination rationale is mechanistic and traditional. [6,7,8]
Doses studied: Common product range: 500-1500 mg Lion's Mane (fruiting-body or dual-extract) + 500-1000 mg Reishi (dual-extract preferred for triterpenes + polysaccharides), divided across the day.
Cordyceps
Limited evidenceReishi and Cordyceps both contribute beta-glucans to immune-mushroom stacks; effects overlap rather than synergise.
Both Cordyceps (most often C. militaris) and Reishi (Ganoderma lucidum) contain cell-wall beta-glucans that interact with pattern-recognition receptors (Dectin-1, TLR2/4) on innate immune cells. Cordyceps additionally contributes cordycepin and adenosine analogues with reported effects on exercise tolerance and mitochondrial function. The combination overlaps in immune mechanism rather than complementing it; the rationale for co-administration is mostly traditional Chinese medicine practice and product positioning (mushroom-complex SKUs).
Evidence: Xu 2011 (Am J Chin Med 39:15) reviews Reishi polysaccharide immunomodulation. Cordyceps human trials are limited. No RCTs evaluate the combination directly; combination rationale is mechanistic + traditional. [8]
Doses studied: Common product range: 500-1500 mg Cordyceps + 500-1000 mg Reishi (dual-extract preferred), divided across the day.
Chaga
Limited evidenceMycofera mushroom-cluster siblings — both contain β-(1-3,1-6) glucan + species-specific polyphenols (chaga melanin, reishi triterpenoids).
Chaga delivers β-glucan + melanin polysaccharide-protein complexes; reishi delivers β-glucan + ganoderic-acid triterpenoids. Mechanism complementary.
Evidence: Camden NB-502 bundles both.
Doses studied: 300-1000 mg chaga + 300-500 mg reishi extracts daily.
Maitake (Grifola frondosa)
Limited evidenceMycofera mushroom-cluster siblings — different mechanism axes (D-fraction vs ganoderma triterpenoids).
Maitake D-fraction polysaccharide vs reishi ganoderic-acid triterpenoids + β-glucans. Mechanism complementary across two active classes.
Evidence: Camden NB-502 bundles both.
Doses studied: 300 mg maitake + 300-500 mg reishi extracts daily.