Maitake (Grifola frondosa)
Maitake (Grifola frondosa, "Hen of the Woods") is a culinary-medicinal mushroom widely eaten in East Asia and sold in the UK as a food supplement, usually as dried fruiting-body powder or as a standardised polysaccharide extract. UK and EU authorities set the baseline here: there is no UK-authorised health claim for maitake (the Great Britain nutrition and health claims register lists none, and the EFSA Article 13 botanical claims for "natural defences"/immune health and for blood sugar remain on hold and unapproved), the NHS does not provide or endorse mushroom supplements, and Cancer Research UK states there is not enough evidence that maitake has anti-cancer or cancer-prevention effects. Beneath that authoritative layer, Camden's own reading of the primary literature adds nuance: the most studied preparation is the proprietary "D-fraction" (and the related MD-fraction), a beta-(1-6)/(1-3)-glucan proteoglycan from the fruiting body, and small early-phase trials in cancer-survivor populations have shown measurable but mixed immunological effects — the dose-response is non-monotonic, and "more is not better".
Camden Medicals editorial · Last reviewed 6 May 2026 · Next review May 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
- Standardised D-fraction extracts in trials: 0.1-5 mg/kg twice daily (Deng 2009 dose-escalation) or 12 capsules/day during chemoradiotherapy (Hu 2022, dose by manufacturer protocol). Crude dried fruiting-body powder: 100-500 mg/day per manufacturer convention, no published efficacy at these doses.
- Top use evidence
- Moderate
On this page
What it is
Maitake (Grifola frondosa) is a polypore mushroom native to temperate forests of East Asia, eastern North America, and parts of Europe. The Japanese name "maitake" means "dancing mushroom" — folkloric origin: foragers were said to dance on finding it. The fruiting body is a large grey-brown rosette of overlapping fan-shaped caps, harvested at the base of oak and other hardwoods.
Maitake is rich in beta-glucans — primarily β-(1-6)-glucans with β-(1-3) branches, a structural pattern that distinguishes it from the β-(1-3)/(1-6) glucans of shiitake. The most-studied isolated preparation is "D-fraction" (and its more refined relative "MD-fraction"), a proteoglycan extracted from the fruiting body. D-fraction is the focus of nearly all published clinical research on maitake; generic dried-mushroom powder is not the same product.
UK food-supplement-grade maitake is sold either as crude dried fruiting-body powder, as mycelial biomass, or as standardised polysaccharide extracts. Dose, evidence base, and cost differ substantially between these forms. Mycelial biomass grown on grain substrate is largely undigested grain by weight, not mushroom — the substrate-vs-fruiting-body distinction is the single most useful question to ask of any maitake product.
At a glance
- No UK-authorised health claim. Marketing must stay descriptive (culinary tradition, mushroom blend) and must not use immune-boosting or "natural defences" framing.
- The clinical research footprint is on D-fraction and MD-fraction (proprietary polysaccharide extracts) — not on generic dried-mushroom powder. Generic powder has no efficacy data of its own.
- A 2009 phase I/II MSK Cancer Center trial in postmenopausal breast cancer survivors showed that maitake extract produces BOTH immune-stimulatory AND immune-inhibitory effects, with a non-monotonic dose-response. The headline is more nuanced than supplement marketing implies.
- A 2022 RCT (n=141) of Maitake D-fraction during chemoradiotherapy for advanced laryngeal/pharyngeal cancer showed reduced treatment-related adverse events and better quality-of-life. This is hospital-supervised, not self-medication.
- Most "mushroom complex" supplements deliver maitake at 100-300 mg/day in a multi-mushroom blend — well below extract doses studied in research.
What people use it for
Adults seeking general "immune support"
There is no UK-authorised health claim for maitake or for beta-glucans for immune function. Marketing must therefore stay descriptive. Small phase-I/II trials of standardised D-fraction extract have shown measurable changes in immune-cell signalling — but with both stimulatory AND inhibitory effects, and a dose-response that is not "more = better". [4]
Some evidenceLimitedCancer patients considering maitake during treatment
UK guidance is cautious here: Cancer Research UK finds insufficient evidence that any mushroom has cancer-treatment efficacy and notes most mushroom-extract supplements are untested for interactions with cancer medicines, and the NHS position is that anyone in treatment tells their care team about supplements. The 2022 RCT of Maitake D-fraction during chemoradiotherapy for laryngeal/pharyngeal cancer showed reduced treatment-related adverse events and better QoL — but this was hospital-supervised, used a specific dose schedule, and does not establish a basis for self-medication. Off-the-shelf mushroom-complex capsules are NOT the same product as the trial preparation. [5,6]
Some evidenceModerateAdults using maitake as a culinary mushroom
Maitake is a well-tolerated edible mushroom and a useful component of a varied diet. Culinary-tier consumption (cooked) carries no specific safety concern in healthy adults.
Popular, not provenInsufficientPeople with diabetes considering maitake for blood-sugar effects
Animal and small early-stage human studies have explored maitake polysaccharides for glycaemic effects (the so-called "X-fraction"). The clinical evidence base is too thin for a recommendation; people with diabetes should NOT substitute maitake for prescribed therapy and should monitor glucose if they choose to add it.
Popular, not provenInsufficient
How it works
Maitake D-fraction beta-glucans are recognised by Dectin-1 and complement-receptor-3 (CR3) on innate immune cells, modulating macrophage and dendritic-cell signalling in pre-clinical models. Human trials show this signalling produces measurable but bidirectional effects (both stimulatory and inhibitory), with a non-monotonic dose-response — the assumption that "more is more" does not hold.
Common myths
Myth""Maitake boosts your immune system.""
RealityNo UK-authorised "immune support" health claim for maitake. The most-cited human study (Deng 2009, MSK-CC) actually concluded that maitake produces both immune-enhancing AND immune-suppressing effects, with intermediate doses sometimes opposing high or low doses. The honest framing is "modulates" — not "boosts" — and the clinical relevance is unclear. [4]
Myth""Maitake fights cancer.""
RealityThe 2022 chemoradiotherapy trial improved supportive-care outcomes (toxicity reduction, QoL) — it did NOT show that maitake cured cancer or improved survival. Marketing maitake as an anti-cancer agent is a medicinal claim, not a permitted food-supplement claim, and conflates supportive care with cure. [5]
Myth""Maitake D-fraction is in any maitake supplement.""
RealityD-fraction is a specific extracted proteoglycan made by a small number of manufacturers under documented protocols. Most off-the-shelf "maitake" products are crude dried fruiting-body powder, mycelial biomass, or a generic mushroom extract — none of which carry D-fraction's research footprint without explicit standardisation and assay.
Myth""Maitake controls blood sugar.""
RealityThe "X-fraction" hypoglycaemic literature is preliminary — animal models and small early-phase human work — and the dose-response is unclear. Anyone with diabetes should manage glucose with prescribed therapy and lifestyle, not substitute maitake. If you choose to add it, monitor glucose closely and tell your diabetes team.
Common online questions
Synthesised from the questions UK shoppers most often ask online about Maitake (Grifola frondosa). Each answer is editorial and links to its evidence in the Sources list below.
Does maitake "boost" my immune system?
There is no UK-authorised health claim that says so. The strongest published trial (a phase I/II at Memorial Sloan-Kettering, 2009) actually found that maitake had BOTH immune-stimulatory and immune-suppressive effects, and that intermediate doses sometimes did the opposite of high or low doses. The biology is more nuanced than "more = better" supplement marketing suggests. [4]
Is maitake safe in pregnancy?
Cooked maitake at culinary food-tier intake carries no specific concern. Concentrated supplements have not been adequately studied in pregnancy and there is no UK guidance recommending maitake supplementation in pregnancy. The default position is to stay at food-tier intake during pregnancy and discuss any concentrated mushroom supplement with your midwife or GP.
Can I take maitake during chemotherapy?
Talk to your oncology team before starting any mushroom or beta-glucan supplement during chemotherapy. The 2022 D-fraction trial during chemoradiotherapy was a specific hospital-supervised intervention with a named product and dose schedule — those results do not transfer to off-the-shelf maitake capsules. Some chemotherapy regimens are sensitive to immunomodulator interactions; the safe default is "ask first". [5,6]
Will maitake help my blood sugar?
The published evidence is preliminary — mostly animal models and small early-stage human studies — and not strong enough to support a clinical recommendation. People with diabetes should not substitute maitake for prescribed therapy. If you do add maitake to a stable diabetes regimen, monitor glucose closely and tell your diabetes team.
⚖️ The official position
What may lawfully be claimed about Maitake (Grifola frondosa) in Great Britain. This is a regulatory position, not an evidence grade.
No health claim is authorised for this use in Great Britain.
Maitake (Grifola frondosa) has a history of traditional use. Authorised health claims require a positive EFSA scientific opinion; none has been issued for this use.
🔬 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.
Immune signalling in cancer survivors (oral D-fraction extract)
LimitedEvidencelimitedUK/EU guidance position (primary): no authorised health claim links maitake to immune function — the GB nutrition and health claims register lists none, and the EFSA Article 13 immune/"natural defences" claim remains on hold and unapproved. Camden's secondary reading of the primary literature: A 2009 phase I/II dose-escalation study at Memorial Sloan-Kettering Cancer Center enrolled 34 postmenopausal breast-cancer survivors free of disease and treated with oral maitake liquid extract at 0.1-5 mg/kg twice daily for three weeks. The trial reported a statistically significant association between maitake dose and immunological function (p < 0.0005), but the effect was non-monotonic — intermediate doses had different effects from low or high doses, and the response included both stimulatory and inhibitory shifts. The authors specifically warned that "botanical agents produce more complex effects than assumed, and may depress as well as enhance immune function". This is a critical interpretive point for any consumer marketing. [4]
Adjunctive supportive care in advanced head and neck cancer (chemoradiotherapy)
ModerateEvidencemoderateUK guidance position (primary): Cancer Research UK states there is not enough evidence that any mushroom, including maitake, has anti-cancer or cancer-prevention effects, and that most mushroom-extract supplements are untested for interactions with medicines; the NHS does not endorse supplement use during treatment. Camden's secondary reading of the primary literature: A 2022 randomised placebo-controlled trial (n = 141) of oral Maitake D-fraction capsules during concurrent chemoradiotherapy for advanced laryngeal/pharyngeal cancer reported lower frequency of severe treatment-associated adverse events, better global quality-of-life scores, and faster QoL recovery to baseline at 6 months. This is hospital-supervised oncology supportive care — not a green light for self-medication. UK relevance: maitake is not a licensed adjunctive medicine; trial conditions and product are specific. [5]
Hypoglycaemic effect / type-2 diabetes
InsufficientEvidenceinsufficientUK/EU guidance position (primary): no authorised blood-sugar health claim exists for maitake — the GB nutrition and health claims register lists none, and the EFSA Article 13 blood-sugar claim remains on hold and unapproved. Camden's secondary reading of the primary literature: Animal-model evidence and small early-stage human work has explored maitake's "X-fraction" for glycaemic effects. The published RCT footprint is too thin and too short to support a clinical recommendation. People with diabetes should not substitute maitake for prescribed therapy.
General "wellness" / "energy" claims
InsufficientEvidenceinsufficientNo UK-authorised claim. No high-quality RCT evidence at food-supplement doses. Marketing this way is not permitted under the Nutrition and Health Claims Regulation.
Safety
Cooked maitake at food-tier intake is well-tolerated. Concentrated maitake supplements have a thin clinical-evidence base in healthy adults; the published trials show maitake has both immune-stimulatory AND immune-suppressive effects, not a simple "boost"; chemotherapy patients should not start any mushroom supplement without their oncology team's input.
Talk to your pharmacist or GP first if you:
- You are receiving cancer treatment or are immunosuppressed (post-transplant, biologic-DMARD therapy, HIV) — mushroom beta-glucans interact theoretically with immune signalling and your oncology / immunology team should approve any supplement.
- You take warfarin or other anticoagulants — high-dose mushroom supplements have weak theoretical interaction signals; check INR if starting.
- You have diabetes or take insulin / sulphonylureas — maitake polysaccharides have weak hypoglycaemic signals in early studies; monitor glucose and tell your diabetes team.
- You are pregnant or breastfeeding and considering a concentrated maitake supplement (food-tier maitake in cuisine is fine; concentrated supplements are unstudied).
Common side effects: Generally well-tolerated at culinary intake. Concentrated extracts: nausea, joint swelling, rash, and pruritus reported individually in dose-escalation trials.
Pregnancy and breastfeeding
Cooked maitake at culinary food-tier intake carries no specific concern. Concentrated maitake supplements are unstudied in pregnancy. Default position: stay at food-tier intake; discuss concentrated supplements with your midwife or GP.
As pregnancy — culinary intake fine; concentrated supplements unstudied; default to food-tier intake.
Talk to your GP, midwife, or pharmacist before starting any supplement during pregnancy or breastfeeding.
More clinical detail (for clinicians and informed readers)
Contraindications
- Documented mushroom hypersensitivity.
- Active immunosuppression for transplantation or biologic therapy — discuss with prescribing team.
Drug interactions
- Insulin / sulphonylureas / other antidiabetic agents — theoretical additive hypoglycaemic effect from maitake polysaccharides. Monitor glucose; the signal is weak but biologically plausible.
- Warfarin / DOACs — theoretical interaction (consistent with the broader mushroom-polysaccharide signal); check INR if starting high-dose extracts.
- Immunosuppressants (ciclosporin, tacrolimus, mycophenolate, biologic DMARDs) — theoretical antagonism. Discuss with prescriber before starting any mushroom supplement.
- Cytotoxic chemotherapy — no documented direct interaction; immunomodulator supplements during chemotherapy should be cleared with the oncology team.
This is not an exhaustive list. Always tell your prescriber and pharmacist about every supplement you take.
Common side effects
- Generally well-tolerated at culinary intake.
- GI symptoms (nausea, bloating) occasionally reported with concentrated extracts.
Rare side effects
- Joint swelling and rash with pruritus — both reported as grade-I events in the 2009 MSK-CC dose-escalation trial.
- Allergic reactions including urticaria in occupational mushroom-cultivation workers.
How to take it
- Typical supplemental range
- Standardised D-fraction extracts in trials: 0.1-5 mg/kg twice daily (Deng 2009 dose-escalation) or 12 capsules/day during chemoradiotherapy (Hu 2022, dose by manufacturer protocol). Crude dried fruiting-body powder: 100-500 mg/day per manufacturer convention, no published efficacy at these doses.
- Timing
- No specific timing requirement.
How to spot quality
Look for
- Species named in full: "Grifola frondosa" — there are several Grifola species, only frondosa is the studied one.
- Part of the mushroom declared: "fruiting body" is the well-studied part. "Mycelium on grain" is a different — and largely undigested grain — preparation by weight.
- Standardisation: declared β-glucan percentage from a third-party assay, OR declared D-fraction / MD-fraction content with batch documentation. "Maitake powder" with no spec is the commodity tier.
- GMP-certified manufacture; ideally a heavy-metals screen (mushrooms accumulate substrate metals).
- Substrate disclosure for cultivated mushroom mycelium (hardwood vs grain).
Red flags
- "Boosts immune system" / "natural defences" / "immunity" marketing — not a permitted UK claim.
- "Anti-cancer" / "tumour" / "fights cancer" wording — not a permitted claim and conflates supportive-care trial findings with cure.
- "Blood-sugar control" / "lowers HbA1c" / "manages diabetes" wording — not a permitted claim and the evidence base does not support clinical use.
- D-fraction or MD-fraction content claimed without a milligram declaration or third-party assay.
- Multi-mushroom blends with no per-mushroom milligram declaration ("proprietary blend X mg") — you cannot work out the maitake dose.
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.
Shiitake (Lentinula edodes)
Limited evidenceMycofera mushroom-cluster siblings — both deliver β-(1-3,1-6) glucan via Dectin-1.
D-fraction (maitake) + lentinan (shiitake) — overlapping but distinct β-glucan preparations. Mechanism additive on innate-immune axis.
Evidence: Camden NB-502 Mushroom Complex bundles both.
Doses studied: 300 mg maitake + 300 mg shiitake extracts daily.
Found in Camden: Mycofera™ Mushroom Complex 120 Capsules
Reishi
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.
Found in Camden: Mycofera™ Mushroom Complex 120 Capsules
Beta-Glucan (β-glucan)
Limited evidenceMaitake D-fraction is a canonical β-(1-3,1-6) glucan preparation — Camden beta-glucan is the molecular pillar.
D-fraction is the most-trialled maitake β-glucan isolate (Nanba 1997 onward). Mechanism: Dectin-1 / CR3 innate immune signalling.
Evidence: Camden beta-glucan covers cluster.
Doses studied: 300-1000 mg maitake D-fraction-standardised extract daily.
Found in Camden: Mycofera™ Mushroom Complex 120 Capsules