Maitake Supplement Forms, Dosing & Safety
5 mg/kg twice daily
The maximum dose in the only published human dose-escalation trial for maitake extract. Safe at all five dose levels in 34 breast cancer patients.
Deng G et al., J Cancer Res Clin Oncol, 2009
34 patients
enrolled in the dose-escalation trial
5 dose levels
0.1 to 5 mg/kg twice daily tested
12 weeks
longest sustained-dose safety monitoring (Wesa 2015)
Deng G et al., J Cancer Res Clin Oncol, 2009
View as image ↗In 2009, researchers at Memorial Sloan Kettering enrolled 34 postmenopausal breast cancer patients and gave them maitake extract at five escalating doses, ranging from 0.1 mg/kg all the way up to 5 mg/kg twice daily. No serious adverse events at any level. But the more interesting finding wasn't the safety data. It was that the lowest doses sometimes showed more consistent immune stimulation than the highest ones. More wasn't reliably better.
That single finding from the only published human dose-escalation trial for maitake D-fraction dosage reshapes how to read supplement dosing guidance. The evidence base is limited: two clinical trials with real dosing data, a handful of case series, and commercial guidance developed from those studies. But what exists points somewhere specific, and it's not toward "take as much as you can."
This article is part of the broader maitake mushroom guide. Here we focus on one question: what do human studies actually tell us about how to dose D-fraction and its related extracts?
Key Takeaways
- The only published dose-escalation trial (Deng 2009, n=34) tested D-fraction from 0.1 to 5 mg/kg twice daily; all five levels were well tolerated in breast cancer patients
- Paradoxically, lower doses (0.1 to 0.5 mg/kg) showed more consistent immune stimulation than higher doses in Deng's trial; the dose-response was not linear
- General wellness commercial dosing: 12 to 25 mg standardized D-fraction daily, or up to 2,500 mg whole mushroom powder (Mayell 2001 review)
- The longest sustained-dose safety data: 3 mg/kg twice daily for 12 weeks in myelodysplastic syndrome patients, well tolerated (Wesa 2015)
- MD-Fraction (an enhanced, more concentrated form of D-Fraction) showed optimal immunological response at 5 to 7 mg/kg/day in cancer case series, a different product with a different dose range (Kodama 2002)
- Warfarin, diabetes medications, and antihypertensives all have documented interactions with maitake that affect how dosing decisions should be made (Ulbricht 2009 systematic review)
Why D-Fraction, MD-Fraction, and Whole Powder Have Different Dose Ranges
Not every maitake supplement is the same product, and the dose ranges don't transfer between forms. This is the single most important thing to understand before looking at any specific number.
D-Fraction is a concentrated extract standardized to roughly 30% proteoglycans, a class of immune-active compounds made of protein chains bound to sugar molecules. It's extracted exclusively from the fruiting body of the mushroom using hot-water extraction, which is required to pull the beta-glucan compounds out of the mushroom's cell walls in a bioavailable form. D-Fraction is the most-studied maitake extract for immune support and is the form used in both of the major human clinical trials.
MD-Fraction is a more refined and more potent version of D-Fraction. It was developed after D-Fraction with higher bioactive concentration. The clinical dose range for MD-Fraction runs considerably higher than the range used in D-Fraction trials: 5 to 7 mg/kg/day from Kodama et al.'s cancer case series.[3] Using MD-Fraction dosing numbers for a standard D-Fraction product, or vice versa, gives you the wrong reference point entirely.
Whole mushroom powder is not an extract. It's dried and ground mushroom tissue. Without hot-water extraction, the beta-glucans in raw maitake powder are largely locked behind chitin cell walls that the human digestive system cannot break down efficiently. The Mayell 2001 review[6] placed general whole-powder dosing at 500 to 2,500 mg per day, a range that looks completely different from the milligram doses used for standardized extracts but reflects the much lower concentration of active compounds per gram of product.
The differences between maitake supplement forms in more detail cover the extraction process and bioavailability differences. The essential point here is that D-Fraction, MD-Fraction, and whole powder are different products with different clinical evidence and different dose ranges.
General Wellness Dosing: Where the 12 to 25 mg Figure Actually Came From
The 12 to 25 mg per day range for standardized D-Fraction extract appears across commercial products and consumer guides. Understanding where it originated matters for evaluating its reliability.
Mayell's 2001 narrative review[6] documented the commercial dosing guidance that existed at the time: 12 to 25 mg of standardized D-Fraction concentrate daily for general wellness and immune support. This guidance came from the researchers who developed D-Fraction, primarily Dr. Hiroaki Nanba's group at Kobe Pharmaceutical University, the scientists who created the extract and built its commercial presence through Mushroom Wisdom products.
It was not derived from a placebo-controlled efficacy trial testing those specific doses in healthy adults. There's no randomized trial that enrolled healthy volunteers, gave them 12 mg versus 25 mg versus placebo, and found that the 12 to 25 mg range produced measurable immune benefits. The range reflects the product developers' clinical experience and early case observation, translated into a starting recommendation.
For context: a 70 kg adult taking 20 mg of D-Fraction gets approximately 0.3 mg/kg per day. The lowest dose in Deng's clinical trial,[1] 0.1 mg/kg, was given twice daily, making it 0.2 mg/kg total per day. General wellness commercial dosing falls in the same rough neighborhood as the bottom of the clinical trial range, but the clinical trial was studying cancer patients, not healthy people.
For whole mushroom powder, the 500 to 2,500 mg range reflects typical dietary supplement servings. Product concentration varies widely because standardization to specific bioactive percentages isn't universal across whole-powder products.
Where Each Dose Actually Sits
Commercial Wellness Dosing Sits at the Bottom of the Tested Range
Every regimen normalized to milligrams per kilogram of body weight per day. The general-wellness commercial dose is a fraction of what the human trials tested — and MD-fraction is a separate product with its own higher range, not a higher D-fraction dose.
Bar length is scaled against the highest dose tested in humans (10 mg/kg/day, Deng’s top cohort). Clinical-trial doses were used in cancer and blood-disease patients under medical supervision — not as general-wellness recommendations.
Sources: Deng et al. 2009 (J Cancer Res Clin Oncol); Wesa et al. 2015 (Cancer Immunol Immunother); Kodama et al. 2002 (Altern Med Rev); Mayell 2001 (Altern Med Rev).
Deng 2009: Five Doses, 34 Patients, the Only Human Dose-Escalation Trial
Everything we know about safe D-Fraction dosing across a range of doses in humans comes from one study: the 2009 phase I/II trial by Deng and colleagues at Memorial Sloan Kettering Cancer Center.[1]
Deng enrolled 34 postmenopausal breast cancer patients and assigned them to one of five dose levels: 0.1, 0.5, 1.5, 3, or 5 mg/kg of maitake extract, taken twice daily for three weeks. This was a dose-escalation design, the kind of study built to find the safety ceiling by testing progressively higher doses. Every level was well tolerated. No serious adverse events were attributed to the maitake extract across all 34 patients.
The safety data is the primary contribution of this trial. A 100-fold dose range, from 0.1 mg/kg to 10 mg/kg total daily (5 mg/kg twice daily), produced no serious harms in this population. For anyone researching D-fraction safety, that range defines what has actually been tested in humans.
Deng et al. (2009) · Journal of Cancer Research and Clinical Oncology
- Population
- 34 postmenopausal breast cancer patients, disease-free after initial treatment
- Intervention
- Oral maitake liquid extract at 0.1, 0.5, 1.5, 3, or 5 mg/kg twice daily for 3 weeks (five sequential cohorts)
- Finding
- No dose-limiting toxicity at any level across a 50-fold dose range. Immune parameters shifted, but not linearly with dose — lower cohorts sometimes showed more consistent stimulation than higher ones.
Deng et al., J Cancer Res Clin Oncol, 2009
The immune measurements were more complicated. Deng used a battery of immune cell markers to track whether the extract was having any measurable effect on immune function. Something was happening. The extract did influence immune parameters. But the pattern wasn't clean.
For the maitake liquid vs. capsule comparison and how doses translate between forms, the Deng trial used a specific maitake extract product. The body-weight dosing method (mg/kg) that clinical trials use is the framework that liquid drop-based commercial dosing is built around, as discussed below.
The Counterintuitive Finding: Lower Doses Showed More Consistent Immune Effects
This is the part of Deng's trial that no competitor covers, and it's the most practically relevant finding for anyone reading supplement dosing guidance.
When Deng's team analyzed immune function across their five dose groups, the relationship between dose and immune stimulation wasn't linear. At some immune markers, the lower dose groups (0.1 and 0.5 mg/kg) showed more consistent stimulation than the higher dose groups at 3 and 5 mg/kg. Higher doses sometimes appeared to suppress the same immune parameters that lower doses stimulated.[1]
This kind of result, where a biological system responds differently at higher concentrations than at lower ones and sometimes in the opposite direction, is known as a biphasic or non-monotonic dose-response. It's well documented in immunology. The immune system is not a volume knob. It's a network of feedback loops, and some immune-modulating compounds activate inhibitory mechanisms at high concentrations that they don't trigger at low ones.
Deng was appropriately careful about over-interpreting this finding. With 34 patients across five groups, the subgroup sizes were too small to draw firm conclusions about which dose is optimal for immune stimulation. But the finding matters for one specific reason: the assumption that higher maitake doses produce better immune outcomes is not supported by the best available data. The evidence is uncertain, not directional toward higher doses.
This is important context for any marketing language that implies therapeutic benefit scales with dose.
Wesa 2015: What Happened When Patients Took 3 mg/kg for Twelve Weeks
Deng's trial ran for three weeks. The longest continuous safety monitoring came from a 2015 phase II study by Wesa and colleagues, published in Cancer Immunology and Immunotherapy.[2]
Wesa enrolled patients with myelodysplastic syndrome (MDS), a group of blood and bone marrow conditions that affect how the body produces blood cells. These patients received 3 mg/kg of maitake extract twice daily for 12 weeks.
The treatment was well tolerated. Both neutrophil and monocyte function improved over the 12-week period. Neutrophils and monocytes are two types of immune cells that are often impaired in MDS. No serious adverse events were attributed to the extract.
Three points make the Wesa trial specifically useful for understanding sustained dosing.
First, MDS patients are immunocompromised and often on other treatments. If maitake extract were going to cause problems at 3 mg/kg, a medically complex, immunocompromised population would be more likely to show them than healthy adults. The clean tolerability in this group is meaningful.
Second, 3 mg/kg twice daily (6 mg/kg total daily) is a substantial dose. For a 70 kg adult, that's 420 mg of extract per day. It is well above any commercial wellness recommendation and at the lower end of the clinical trial range tested by Deng.
Third, 12 weeks of continuous use at that dose is the longest safety monitoring window in any published maitake clinical trial. It's still a short window in the context of long-term supplementation, but it's what the evidence base contains.
For detailed safety information, adverse events, and drug interaction data, a separate article covers what these trials found beyond the dosing question.
MD-Fraction Has Its Own Dose Range: It's Not the Same Product as D-Fraction
Kodama and colleagues reviewed MD-Fraction cancer case series data in a 2002 paper in Alternative Medicine Review.[3] Their finding: 5 to 7 mg/kg per day of MD-Fraction produced the most significant immunological responses in cancer patients across the case series they analyzed.
MD-Fraction is a more refined version of D-Fraction with higher bioactive concentration. It was developed after D-Fraction specifically to increase potency. Milligram for milligram, MD-Fraction delivers more active compound than standard D-Fraction. The dose ranges from MD-Fraction research don't translate directly to standard D-Fraction products.
For a 70 kg adult, 5 to 7 mg/kg/day of MD-Fraction works out to 350 to 490 mg of that specific concentrated extract per day. If you are taking a standard D-Fraction product and apply the MD-Fraction dose numbers to it, you're using guidance from a different product entirely.
Kodama's separate 2003 study[4] looked at standard D-Fraction and natural killer (NK) cell activation in cancer patients. NK cells are immune cells that identify and destroy tumor cells and virus-infected cells without needing prior exposure to a specific threat. The dosing context in Kodama's 2003 work was consistent with commercial D-Fraction ranges, not the higher MD-Fraction doses, confirming that the two products operate with different dose guidance.
To use maitake extract dosing guidance correctly, you need to identify which form you're actually looking at. For understanding the cancer research behind D-Fraction specifically, that evidence base is covered in depth separately.
Body-Weight Dosing: How to Scale D-Fraction Like the Clinical Trials Did
Clinical trials use milligrams per kilogram (mg/kg) because fixed doses mean different things for different body sizes. Twenty milligrams of D-Fraction is 0.3 mg/kg for a 70 kg person and 0.4 mg/kg for a 50 kg person. The mg/kg method removes that variability.
The commercial body-weight dosing convention, most clearly documented in Mayell's 2001 review,[6] translates to liquid form as approximately 1 drop per kilogram of body weight per day, divided across three doses. The Mushroom Wisdom product line, developed by the same group that created D-Fraction, built its liquid dosing instructions around this convention: a standardized liquid where the drop volume converts to a specific mg amount at that concentration.
For a 70 kg adult: roughly 70 drops total per day, divided into about 23 drops taken three times daily. For a 50 kg person: roughly 50 drops divided across three doses. The drop count scales linearly with body weight.
For capsule-based D-Fraction products, the conversion requires knowing two things: how many milligrams of extract are in each capsule, and what percentage of that is the active proteoglucan fraction. A product standardized to 30% proteoglycans with 25 mg of D-Fraction per capsule delivers approximately 7.5 mg of active compounds per capsule. Two capsules per day at that product would provide 15 mg total, the low end of the general wellness range.
The gap between commercial wellness dosing and clinical trial dosing is substantial. The 0.5 mg/kg dose from Deng's trial,[1] the second-lowest tested, works out to 35 mg for a 70 kg person taken twice daily, or 70 mg total per day. That's already above the top of the commercial wellness range. The 3 mg/kg Wesa dose[2] works out to 420 mg daily, roughly 20 times the typical commercial recommendation.
Clinical trial doses were designed for patients with specific immune diseases, not for healthy adults. The clinical evidence doesn't support scaling commercial wellness doses up to clinical trial levels for general use.
Research vs. Retail
Maitake D-fraction (standardized extract): Research vs. commercial doses
What research used
0.2 to 10 mg/kg/day
Oral liquid extract
Twice daily · 3 weeks (Deng 2009) to 12 weeks at 6 mg/kg/day (Wesa 2015)
Tested in breast cancer and myelodysplastic syndrome patients under medical supervision
What supplements sell
12 to 25 mg/day (≈0.2 to 0.4 mg/kg for a 70 kg adult)
Oral liquid drops or capsules
Once to three times daily
Standardized D-fraction concentrate; drop-based liquids scaled ~1 drop per kg body weight
General-wellness dosing sits at the very bottom of the clinical range and was set by the product developers from clinical observation, not a placebo-controlled dose-finding trial in healthy adults. The clinical doses are an order of magnitude higher and were studied only in patients with immune disease.
- *MD-fraction (5 to 7 mg/kg/day, Kodama 2002) is a different, more concentrated product — do not apply its numbers to standard D-fraction.
- *Higher is not reliably better: Deng's trial found a non-linear immune response.
- *This is informational only and not a dosing recommendation.
Deng 2009; Wesa 2015; Mayell 2001
For a full comparison of how liquid, capsule, and powder forms convert between each other, and what bioavailability data exists for each, the maitake liquid vs. capsule vs. powder comparison covers the conversion math and form-specific considerations in detail.
Three Drug Interactions That Change What's Safe to Take
Ulbricht and colleagues' 2009 systematic review in the Journal of the Society for Integrative Oncology[5] is the most comprehensive documentation of maitake drug interactions. Three interactions are specific enough to affect dosing decisions.
Blood thinners (warfarin, other anticoagulants): Maitake beta-glucans have antiplatelet activity, meaning they reduce the tendency of platelets to clump together and form clots. Combined with warfarin or other anticoagulants, the blood-thinning effect is additive. Ulbricht's review documented this interaction and noted that anyone on anticoagulants using maitake extract should have INR monitoring, and that discontinuing maitake two weeks before surgery is prudent. At higher doses, the antiplatelet contribution from maitake is proportionally greater.
Diabetes medications (metformin, insulin, sulfonylureas): Maitake polysaccharides lower blood glucose independently, as shown in both animal research and the PCOS clinical trial data. Combined with medications that also lower blood sugar, the effect stacks. For anyone on diabetes medications, higher maitake doses create a higher risk of blood sugar dropping lower than intended. The blood sugar research on maitake covers this evidence base in detail.
Blood pressure medications (antihypertensives): Maitake has mild blood-pressure-lowering activity through its polysaccharides. Combined with prescription antihypertensives, the combined effect may exceed what either produces alone. Ulbricht's review[5] flagged this as an additive interaction to monitor.
These three interactions don't mean maitake extract is contraindicated with those medications. They mean that the dose calculation for someone on warfarin, diabetes medications, or antihypertensives involves more variables than it would for a person not on those drugs.
Drug interactions that scale with dose
ModerateThree common medication classes interact with maitake — and the risk grows as the dose rises
Concern
Maitake beta-glucans and polysaccharides have antiplatelet, glucose-lowering, and mild blood-pressure-lowering activity. Combined with warfarin or other anticoagulants, diabetes medications (metformin, insulin, sulfonylureas), or prescription antihypertensives, these effects are additive — and the higher clinical-trial doses contribute proportionally more than general-wellness doses.
What the research says
These interactions are manageable, not absolute contraindications, but they change the dose calculation. Ulbricht's systematic review recommends INR monitoring for anyone on anticoagulants and discontinuing maitake about two weeks before surgery.
Particularly relevant for: People taking anticoagulants, diabetes medications, or blood-pressure medications
What to do
Clear maitake use with your prescriber if any of these apply, and monitor accordingly. This article is educational and is not medical advice.
Ulbricht et al., Journal of the Society for Integrative Oncology, 2009
The Bottom Line
The D-fraction dosage evidence comes from two clinical trials in patients with cancer or blood disease, not from efficacy trials in healthy adults. The safety data extends to 5 mg/kg twice daily (Deng 2009) and 3 mg/kg twice daily for 12 weeks (Wesa 2015). The most striking finding from Deng's dose-escalation trial is that lower doses sometimes showed more consistent immune stimulation than higher doses; the dose-response was not linear. General wellness commercial dosing (12 to 25 mg/day) sits well below the clinical trial ranges and was developed from product experience rather than controlled trials at those specific doses. The appropriate clinical doses for therapeutic applications in immune-disease patients are an order of magnitude above general wellness recommendations and were studied in medically supervised settings.
Frequently Asked Questions
Sources & References
- 1RTHM-00289·Deng, Gary et al. (2009). “A phase I/II trial of a polysaccharide extract from Grifola frondosa (Maitake mushroom) in breast cancer patients: immunological effects..” Journal of cancer research and clinical oncology.Study breakdown →PubMed →↩
- 2RTHM-00745·Wesa, Kathleen M et al. (2015). “Maitake mushroom extract in myelodysplastic syndromes (MDS): a phase II study..” Cancer immunology.Study breakdown →PubMed →↩
- 3RTHM-00095·Kodama, Noriko et al. (2002). “Can maitake MD-fraction aid cancer patients?.” Alternative medicine review : a journal of clinical therapeutic.Study breakdown →PubMed →↩
- 4RTHM-00112·Kodama, Noriko et al. (2003). “Effect of Maitake (Grifola frondosa) D-Fraction on the activation of NK cells in cancer patients..” Journal of medicinal food.Study breakdown →PubMed →↩
- 5RTHM-00319·Ulbricht, Catherine et al. (2009). “Maitake mushroom (Grifola frondosa): systematic review by the natural standard research collaboration..” Journal of the Society for Integrative Oncology.Study breakdown →PubMed →↩
- 6RTHM-00080·Mayell, M (2001). “Maitake extracts and their therapeutic potential..” Alternative medicine review : a journal of clinical therapeutic.Study breakdown →PubMed →↩