Researchers have studied a small group of mushroom compounds — mainly beta-glucans, other polysaccharides, and terpenoids — for possible effects on blood sugar. Most of this research is lab and animal work, not human trials. No mushroom compound is proven, in humans, to lower blood sugar or manage diabetes.
This article looks at the compound level: what these substances are, how scientists think they might work, and how far that research has actually gotten. For a species-by-species look at the human and animal studies on specific mushrooms like maitake and reishi, see our cross-species blood sugar research review.
Important safety note before anything else
If you take insulin or any blood sugar-lowering medication, talk to your prescribing clinician before starting any mushroom supplement. Several of the compounds discussed below lower blood glucose in animal studies through mechanisms that could, in theory, add to a medication’s effect and increase the risk of low blood sugar (hypoglycemia). This risk has not been confirmed in human studies, but it has not been ruled out either. Watch for symptoms like shakiness, sweating, confusion, or fainting, and get medical help right away if they happen. For more detail on this specific concern, see our overview of mushroom supplement and medication interactions.
Nothing in this article is medical advice. It does not diagnose any condition, recommend any dose, or tell you to start, stop, or change any medication. Diabetes and prediabetes need to be managed by a qualified clinician.
The three compound types behind most of this research
Mushroom cell walls and fruiting bodies contain a mix of compounds. A small number keep showing up in blood sugar research:
- Beta-glucans. These are complex sugar chains found in the cell walls of most mushroom species. Researchers are particularly interested in high-molecular-weight beta-glucans with a specific branching pattern, which some lab studies suggest may be more biologically active than simpler, smaller versions.
- Polysaccharide-protein complexes. Some mushroom polysaccharides are bound to protein fragments. Maitake’s well-known “D-fraction” is an example of this type of compound, and it has been tested mainly in animal models, not large human trials.
- Terpenoids. These are a large family of compounds especially abundant in reishi, where researchers have identified well over a hundred distinct types. Some terpenoids are being studied for their effect on enzymes involved in carbohydrate digestion.
These compound classes show up across many species, not just one. That is a key difference from thinking about “maitake mushrooms” or “reishi mushrooms” as single ingredients — the actual research question is usually about a specific extracted compound, tested at a specific dose, in a specific lab or animal model.
How scientists think these compounds might affect blood sugar
Published reviews in this area, including a 2021 review in the Journal of Fungi and a 2022 review in Frontiers in Nutrition, describe several proposed mechanisms. None of these have been confirmed as clinically meaningful effects in people. They are hypotheses based mainly on cell and animal research:
- Slowing sugar absorption. Some polysaccharides increase the thickness (viscosity) of material in the digestive tract, which may slow how fast sugar moves into the bloodstream after a meal.
- Affecting insulin-related signaling. In animal studies, certain polysaccharides appear to influence signaling pathways involved in how cells respond to insulin, and how insulin-producing cells in the pancreas survive and function.
- Blocking a digestion enzyme. Some terpenoids inhibit an enzyme called alpha-glucosidase, which normally helps break down carbohydrates for absorption. Slowing this enzyme could, in theory, blunt a blood sugar spike after eating.
- Reducing oxidative stress and inflammation. Several reviews describe polysaccharides increasing antioxidant enzyme activity and reducing inflammatory signaling, both of which are involved in how type 2 diabetes develops and progresses over time.
- Changing gut bacteria. A few studies report shifts in gut microbiota composition after polysaccharide exposure in animals, with downstream effects on insulin sensitivity. This is an early and developing area of research.
Almost all of this mechanistic work comes from cell cultures or animal models, most often mice or rats with chemically induced diabetes. That matters. A mechanism that looks promising in a rodent’s digestive system does not automatically translate to a safe or effective outcome in a person taking a supplement pill. Our guide to the evidence hierarchy explains why cell and animal research sit lower on the reliability scale than human trials.
Where maitake and reishi fit into this compound picture
Maitake (Grifola frondosa) and reishi (Ganoderma lucidum) are two of the most-studied species in this research area, which is likely why they show up so often in supplement marketing.
- Maitake is studied mainly for its D-fraction, a polysaccharide-protein complex. Research here has been almost entirely in animal models. No confirmed, well-designed human trial has established that maitake extract meaningfully lowers blood sugar in people.
- Reishi is studied for both its polysaccharides and its large terpenoid content. A 2025 systematic review of reishi clinical trials found no clear effect on metabolic measures in humans, despite the compound-level mechanisms looking active in lab and animal settings.
Both examples show the same pattern: encouraging cell and animal signals, paired with a lack of confirming human evidence. See our full research profile on maitake for species-specific detail beyond the compound level.
Checklist: is a blood sugar claim backed by real evidence?
Use this checklist when you see a mushroom supplement marketed for blood sugar or diabetes support:
- Does the claim name the actual compound tested (a specific beta-glucan, polysaccharide fraction, or terpenoid), or does it just say “mushrooms”?
- Was the research done in cells, animals, or humans? Marketing rarely specifies this on its own.
- If human research exists, how many people were in the study, and was it a randomized controlled trial or just an observation?
- Does the dose used in the study match the dose in the product you’re looking at?
- Is the claim about managing or treating diabetes, or about a lab measurement changing in a petri dish or a rodent?
- Does the product tell you to stop or reduce your diabetes medication? That is a red flag, not a feature.
Our medication interaction overview and evidence hierarchy guide go into more depth on evaluating claims like these.
Why this evidence does not support using mushroom supplements to manage diabetes
Diabetes management requires monitoring and treatment decisions that only a qualified clinician can make for your specific situation, using tools like the A1C test and, for many people, prescribed medication. According to the National Institute of Diabetes and Digestive and Kidney Diseases, unmanaged high blood sugar over time can lead to serious complications affecting the heart, nerves, eyes, and kidneys.
The mushroom compound research described above has not reached the level of evidence needed to recommend any mushroom extract as a treatment or replacement for medical diabetes care. The gaps are specific and well documented by the researchers themselves:
- Very few randomized controlled trials exist in people with diabetes or prediabetes.
- Existing human studies are often small and short in duration.
- Doses used in animal research frequently do not match what is realistic or available in commercial supplements.
- Structure-activity relationships — which exact molecular features make one polysaccharide more active than another — are still not fully understood.
Reviewers in this field consistently call for larger, well-controlled human trials before any therapeutic claims can be made. That call has not yet been answered at scale.
People who need extra caution
- Anyone on insulin or blood sugar-lowering medication should talk to their care team first, given the theoretical hypoglycemia risk described above.
- Anyone scheduled for surgery should tell their surgical team about any mushroom supplement, since blood sugar and bleeding-related effects can complicate procedures.
- Pregnant or breastfeeding people should be especially cautious, since blood sugar regulation in pregnancy is different and mushroom supplement safety data in this group is limited. See our blood sugar research review for more on at-risk groups.
- Anyone newly diagnosed with diabetes or prediabetes should focus first on the management plan set by their clinician, not on supplement research that has not reached human confirmation.
What ongoing research looks like
Researchers reviewing this field are actively calling for large, well-designed human trials, better understanding of how gut bacteria interact with mushroom polysaccharides, and clearer dosing standards that match what is actually sold in supplements. Until that research exists and is replicated, the honest summary is this: mushroom compounds show real biological activity in cells and animals, but that activity has not been confirmed to help people manage blood sugar or diabetes.
Frequently asked questions
Can eating mushrooms as food lower my blood sugar?
Whole mushrooms are low in carbohydrates and contain fiber, which can be part of a blood sugar-friendly eating pattern. That is different from the concentrated compound research discussed in this article, which mostly involves extracts and isolated fractions tested at doses far higher than what you would get from a normal serving of food. Talk to your clinician or a registered dietitian about how mushrooms fit into your specific diabetes eating plan.
Are maitake or reishi supplements proven to treat diabetes?
No. Despite active research interest, no maitake or reishi supplement has been proven in well-designed human trials to treat or manage diabetes. The strongest evidence for both species currently comes from animal and lab research.
Is it safe to take a mushroom supplement along with my diabetes medication?
Don’t start a mushroom supplement while on diabetes medication without talking to your prescribing clinician first. Some mushroom compounds lower blood sugar in lab and animal studies through mechanisms that could theoretically add to your medication’s effect.
What’s the real difference between eating mushrooms and taking mushroom extract supplements?
Food-level amounts of mushrooms and concentrated supplement extracts are not the same exposure. Supplements are formulated to deliver much higher amounts of specific compounds like beta-glucans, which is exactly why the safety and interaction questions in this article apply to supplements far more than to mushrooms eaten as food.
Educational disclaimer
This article is for general educational purposes only. It summarizes published research and does not diagnose any medical condition, recommend any treatment, or replace advice from a qualified healthcare provider. Always talk to a doctor, pharmacist, or other qualified clinician before starting, stopping, or changing any medication or supplement, especially if you have diabetes, prediabetes, or another condition affecting blood sugar.