Know2eat

Maitake extract

Grifola frondosa

Medicinal Mushrooms

What maitake extract may help with

Ranked by how strong the human evidence is — best supported first.

Best supportedBlood glucose responseNot enough evidence· 3 sources

Then, in order

About Maitake extract

An edible polypore that grows in clusters at the base of oaks, sold as culinary mushroom and as a concentrated beta-glucan fraction. The studied preparations are the proprietary D-fraction and MD-fraction extracts.

Maitake is a good food and a thinly evidenced supplement. The proprietary D-fraction and MD-fraction extracts have been through a small dose-escalation study in postmenopausal breast cancer patients, which found immune parameters moved in both directions depending on dose — a result usually reported in marketing without the second half. Beyond that there are animal glucose studies, a small trial in polycystic ovary syndrome using maitake alongside clomiphene, and very little else. The mushroom itself, eaten as food, is a reasonable source of beta-glucan and, if exposed to ultraviolet light, of vitamin D2.

Sold as
D-fraction liquid extract, MD-fraction capsule, Hot-water extract powder, Dried culinary mushroom
Standardised to
Proprietary fractions are standardised by the manufacturer; generic maitake powder usually is not standardised at all — a product without this marker may not resemble what was studied.
Also known as
Hen of the woods, Dancing mushroom, D-fraction, MD-fraction

Regulation: Sold as a dietary supplement in the US with no pre-market efficacy review. The D-fraction extracts have held investigational drug status for study purposes without reaching approval.

What the research used

The amounts, forms and durations published trials of Maitake extract actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

  • Studied for Immune parameter dose-escalation study

    0.1–5 mg

    Not enough

    Maitake extract per kilogram of body weight, twice daily · 3 weeks

    A phase I study in postmenopausal breast cancer patients. Immune measures rose at intermediate doses and fell at the extremes, which is not a straightforward result and is rarely quoted in full.

  • Studied for Polycystic ovary syndrome

    3000 mg

    Not enough

    Maitake extract tablets, daily · 12 weeks

    A small Japanese study comparing maitake with clomiphene for ovulation induction. It was small, open-label and has not been replicated.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

  • Any time

    Not enough

    No timing comparison exists. Divided dosing in trials was for tolerability.

    Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

The evidence in depth

Best supported: Not enough

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Blood glucose response

Blood Sugar & Metabolic Health
Not enough evidence

Glucose-lowering effects are reported consistently in diabetic rodents and have not been demonstrated in a controlled human trial.

Not enough evidence. Not enough human research to say anything useful yet.

View the 3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Immune function

Immune Health
Not enough evidence

One small dose-escalation study reported changes in immune cell measures, in both directions depending on dose, with no clinical endpoint. That is not a basis for an immune claim.

What may be going on: Beta-glucans in the D-fraction bind innate immune receptors in laboratory systems.

Not enough evidence. Not enough human research to say anything useful yet.

View the 3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

  • Interaction

    Additive with glucose-lowering medication

    Interacts withInsulin, sulfonylureas, other glucose-lowering drugs

    Given the consistent glucose-lowering signal in animal work and a case report of interaction, anyone on insulin or a sulfonylurea should monitor blood glucose if they start maitake extract.

  • Worth knowing

    Proprietary fraction versus mushroom powder

    The small clinical literature used specific proprietary extracts. Generic maitake capsules, and grain-grown mycelium in particular, are different products with unmeasured beta-glucan content and no trial evidence of their own.

  • Interaction

    Warfarin interaction reported

    Interacts withWarfarin

    There is a published case of increased warfarin effect associated with maitake. Anyone anticoagulated should mention it to their prescriber.

  • Avoid

    Immune conditions and cancer treatment

    Interacts withImmunosuppressants, chemotherapy

    An immunomodulating extract is not a neutral addition during immunosuppression, autoimmune disease or active cancer therapy. It belongs in a conversation with the treating clinician.

In the food catalogue

The whole-food form, where one exists. The evidence for a concentrated extract rarely transfers to the food, or the other way round — these are cross-links, not equivalents.

Maitake mushroomsThe culinary mushroom the extract is made from, which supplies…Shiitake mushroomsAnother culinary mushroom with comparable beta-glucan chemistry.

Evidence ratings on this page: 2 not enough evidence.

Supplements are sold in the US without pre-market review of efficacy or safety. Nothing on this page is a recommendation to take Maitake extract, or a dose to follow.