Some mushroom species have lowered blood glucose in animal studies, but no mushroom or mushroom supplement is proven to treat, prevent, or manage diabetes in people. The strongest human evidence, a 2025 systematic review of reishi mushroom trials, found no clear effect on blood sugar or related metabolic measures. Anyone using diabetes medication should talk to their prescribing clinician before adding any mushroom product.
Important Safety Note Before You Read Further
Diabetes medications, including insulin and drugs like metformin or sulfonylureas, are already designed to lower blood sugar. Adding a supplement that also affects glucose can push blood sugar too low, a condition called hypoglycemia. This is not a theoretical risk. A case report published in Annals of Internal Medicine: Clinical Cases in 2025 documented severe hypoglycemia after a person consumed coffee containing reishi mushroom. Warning signs of low blood sugar include shakiness, sweating, confusion, a fast heartbeat, and, in severe cases, loss of consciousness. Anyone on blood-sugar-lowering medication who wants to try a mushroom product should discuss it with their doctor or pharmacist first, and should never adjust a diabetes medication dose without medical guidance.
Understanding Diabetes and Blood Sugar
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), diabetes happens when blood glucose is too high. Left uncontrolled, this can lead to heart disease, nerve damage, eye problems, and kidney disease. NIDDK data shows that roughly 38.4 million Americans, about 11.6 percent of the population, have diabetes, and nearly 1 in 5 of them do not know it. Another 97.6 million American adults have prediabetes, meaning their blood sugar is higher than normal but not yet in the diabetic range. Diabetes takes several forms, including type 1, type 2, gestational diabetes during pregnancy, and rarer monogenic forms. NIDDK’s current diabetes information does not list mushroom supplements as a recognized management tool.
Maitake Mushroom: What the Animal Studies Found
Maitake (Grifola frondosa) has the most laboratory interest for blood sugar among culinary and medicinal mushrooms, but almost all of that evidence comes from animals, not people.
In one study, a compound called Fraction SX, extracted from maitake, favorably influenced blood glucose and blood pressure in rats with chemically induced diabetes. In another animal study, a water-soluble maitake extract lowered circulating glucose and insulin levels in a mouse strain bred to develop diabetes-like symptoms. A third study found that an alpha-glucan compound isolated from maitake’s fruiting body showed anti-diabetic activity in genetically diabetic mice.
These are real, published findings, but they come from rodent models using isolated extracts and fractions, not the whole mushrooms or general supplements sold to consumers. Only a very limited amount of human data exists, far short of a controlled clinical trial. There is currently no well-designed human trial confirming that maitake lowers blood sugar in people with diabetes. Our maitake mushroom research and safety profile grades its human evidence as limited for this reason.
Reishi Mushroom: What the Human Research Found
Reishi (Ganoderma lucidum) has more human research behind it than most other species, which makes it a useful case study in how preliminary interest does not always translate into a clear benefit.
A 2025 GRADE-assessed systematic review and meta-analysis, published in Food Science & Nutrition, pooled data from 17 randomized clinical trials evaluating Ganoderma lucidum’s effects on human health, including cardiovascular and metabolic measures relevant to diabetes risk. The review rated the certainty of evidence as very low and found no clear effect for many of the metabolic and cardiovascular outcomes examined. In plain terms, the best current review of human reishi trials does not support using reishi to manage blood sugar. Our reishi mushroom research profile covers this review and its limitations in more detail.
Evidence Summary by Species
- Maitake, animal study (streptozotocin-diabetic rats): Fraction SX extract favorably influenced blood glucose and blood pressure. No confirmed human trial exists for this finding.
- Maitake, animal study (diabetes-prone mice): A water-soluble extract lowered circulating glucose and insulin. No confirmed human trial exists for this finding.
- Maitake, animal study (diabetic mice): An isolated alpha-glucan compound showed anti-diabetic activity. No confirmed human trial exists for this finding.
- Reishi, human systematic review and meta-analysis (17 trials, 2025): Found no clear effect on most metabolic and cardiovascular measures, with certainty rated very low.
- Reishi, human case report (2025): Documented severe hypoglycemia after consumption of reishi coffee, a safety signal rather than a benefit finding.
Why Animal Findings Do Not Confirm Human Results
Rodent studies use methods, like chemically inducing diabetes or breeding genetically diabetes-prone mice, that do not reflect how type 2 diabetes develops in people over years of diet, genetics, and lifestyle. Animal studies also often use isolated fractions or extracts at concentrations far higher than a typical supplement dose. A finding in mice is a reason for researchers to study a compound further in people, not a reason for a person to expect the same result from a store-bought supplement. Our guide to understanding the evidence hierarchy for mushroom research explains this gap in more detail.
Who Should Use Extra Caution
- People taking insulin or blood-sugar-lowering medication. Combining these with a mushroom product that also affects glucose raises the risk of hypoglycemia, as documented in the reishi coffee case report above.
- People scheduled for surgery. Blood sugar changes can complicate anesthesia and recovery, so some clinicians recommend stopping certain mushroom supplements before a procedure.
- Pregnant or breastfeeding people. There is not enough safety data on mushroom supplements in pregnancy or breastfeeding to recommend their use.
- People with a known mushroom allergy. Mushroom supplements can trigger allergic reactions in sensitive individuals.
- Anyone taking blood-pressure or blood-thinning medication. Some of the same compounds studied for blood sugar have also been studied for blood pressure effects, which can compound medication interactions.
Evidence Gaps and Ongoing Research
No large, well-designed, placebo-controlled human trial has confirmed that any mushroom species meaningfully lowers blood sugar or improves diabetes outcomes in people. Most maitake evidence remains confined to animal models. The most rigorous reishi review to date found very low certainty evidence and no clear benefit. Researchers have not established an effective human dose, a standardized extract, or a defined treatment duration for any mushroom species in relation to blood sugar. Until human trials close these gaps, mushroom supplements cannot be considered a blood sugar management tool. If you want to learn how to evaluate future research as it is published, our consumer’s guide to reading a mushroom clinical trial walks through what to look for.
Frequently Asked Questions
Can mushrooms or mushroom supplements replace my diabetes medication?
No. No mushroom species has human trial evidence strong enough to replace, reduce, or substitute for a prescribed diabetes medication. Never stop or change a diabetes medication without talking to the clinician who prescribed it.
Which mushroom has the strongest research for blood sugar, maitake or reishi?
Neither has strong human evidence. Maitake has more laboratory and animal interest, while reishi has the largest and most recent human systematic review. That reishi review found no clear metabolic benefit, so more research does not currently mean better results for either species.
Is it safe to take a mushroom supplement alongside metformin or insulin?
This should be discussed with your doctor or pharmacist before starting. Because some mushroom compounds may lower blood sugar, combining them with diabetes medication could increase the risk of hypoglycemia, as seen in a published case involving reishi.
Why do promising animal studies so often fail to hold up in human trials?
Animal models use different biology, higher extract concentrations, and artificially induced diabetes that does not match how the disease develops in people. A result in rodents is a starting point for further research, not proof of a human benefit.
Educational Disclaimer
This article is for general educational purposes only and is not medical advice. It does not diagnose any condition, recommend any supplement, or replace guidance from a qualified healthcare professional. If you have diabetes, prediabetes, or any concern about your blood sugar, talk to your doctor before making any changes to your diet, supplements, or medication.