Maitake and Shiitake: What's Actually Known About the Other Two Mushrooms

What does the research say about maitake and shiitake mushroom benefits?

Maitake and shiitake are both food mushrooms with a long culinary history, and both have been studied mainly for a group of natural compounds called polysaccharides — including beta-glucans — that interact with the immune system. Most of that research uses concentrated extracts or purified compounds at amounts far higher than what a typical mushroom-blend supplement contains, and much of it is laboratory or animal work rather than large human trials. This guide separates what's actually been studied from what a supplement label can honestly claim.

What maitake and shiitake are

Maitake (Grifola frondosa) grows in layered, ruffled clusters at the base of trees, which is where its common name "hen of the woods" comes from. It has a long culinary history in Japan, where it's cooked and eaten much like other food mushrooms.

Shiitake (Lentinula edodes) may be the most familiar mushroom of the four in RENEW's blend. It's widely used in home and restaurant cooking across East Asia and, increasingly, in the United States, and it is one of the most widely cultivated food mushrooms in the world.

Both differ from reishi, the woody, rarely-eaten mushroom in RENEW's blend covered in our reishi guide — maitake and shiitake are tender, edible mushrooms in their whole form, though what goes into a capsule is not the mushroom you would cook. RENEW's panel names Maitake (Grifola frondosa) powder (mycelial biomass) and Shiitake (Lentinula edodes) powder (mycelial biomass) — mycelium is the fungus's root-like network, grown and dried, rather than the tender cap harvested and eaten. The culinary history below is about the whole mushroom; the ingredient is the cultivated mycelium.

The immune research — and its limits

A 2023 peer-reviewed review of medicinal-mushroom components describes beta-glucans as a primary group of compounds behind mushrooms' traditional reputation. We cite that review for one thing only — what it says is still unsettled. Much of what it covers is medical-treatment research that has no bearing on a food-grade daily supplement, and none of it was done on RENEW. The review's own conclusion is direct: the underlying mechanisms are not fully worked out, and the authors say longer, well-designed human studies are still needed to confirm mushroom components' effects, establish their safety, and settle on an appropriate amount. That review does not treat maitake as a primary subject at all — its featured mushrooms are lion's mane, reishi, chaga, cordyceps, shiitake, and turkey tail. We did not find a comparable peer-reviewed review focused on maitake that we could read end to end, so we are not going to summarize one here.

None of this research was done on capsule-form mushroom powder blended with other ingredients, and none of it was done on RENEW. It's background for why maitake and shiitake are included in a formula meant to support normal immune function — not a promise about what a serving of RENEW does.

Safety and what to watch for

Shiitake carries one well-documented reaction worth knowing about. Eating raw or undercooked shiitake can trigger a rash researchers call flagellate dermatitis — itchy, whip-like streaks, usually on the trunk and limbs, that typically appear within one to two days of eating the mushroom and clear on their own within a couple of weeks. The case literature attributes it to lentinan, a shiitake polysaccharide, and notes that lentinan is heat-sensitive — its structure changes irreversibly at high cooking temperatures, which is why cooked shiitake usually does not cause the reaction. RENEW's shiitake is disclosed on the panel as a powder (mycelial biomass) rather than a whole raw mushroom. That is not reassurance by itself: the case literature locates lentinan in the mycelium, and the variable that matters in those reports is heat, not whether the mushroom was whole. We do not have processing-temperature data for RENEW's powder, and we have not found research testing whether powder form carries the same reaction — so if you have any mushroom sensitivity, raise this with your doctor before starting.

Maitake's most-discussed interactions involve blood sugar and blood thinners. Memorial Sloan Kettering's herb-interaction database notes that maitake "may increase the effects" of diabetes medications, which could make blood sugar drop lower than intended, and cites a case report linking maitake to an elevated INR — a blood-clotting measurement — in someone taking warfarin.

How this relates to RENEW — and how it doesn't

RENEW's label lists Maitake (Grifola frondosa) powder (mycelial biomass) and Shiitake (Lentinula edodes) powder (mycelial biomass) as two of the four mushrooms — alongside cordyceps, covered in our cordyceps guide, and reishi — inside a combined 1,020 mg proprietary blend, included to support normal immune function. A proprietary blend discloses its total weight and its ingredients, not a separate weight for each one. That means the label doesn't say how many of those 1,020 milligrams come from maitake, how many come from shiitake, or how either compares to the doses used in the research above. Mycelial biomass is also grown on grain and dried with its substrate, and commercial preparations vary widely in how much actual beta-glucan they carry; we do not have a certificate of analysis breaking that out for RENEW's blend. Neither the immune research nor the maitake interaction findings can be read as evidence about what RENEW's maitake or shiitake content specifically does, and we don't claim that they do. (RENEW's label separately discloses Beta Glucan 1,3/1,6 at 1,000 mg as its own ingredient — a different, yeast-derived compound from the mushroom blend's naturally occurring polysaccharides.)

The traditional culinary history and general research above are background for why these two mushrooms are part of an immune-support formula — not a guarantee of a particular outcome. You can see the full blend, and what is and isn't broken out by amount, on the RENEW ingredients page.

Questions to ask your doctor

Bring your full supplement label to your next appointment and ask:

• I take a blood thinner like warfarin. Could a maitake-containing supplement affect my bleeding risk or my INR?
• I take medication for diabetes or blood sugar. Is a mushroom-blend supplement like this safe to combine with it?
• I have a mushroom allergy or sensitivity. Does this product fit my situation?
• Does the lack of separate maitake and shiitake amounts on the label change your advice for me?

These questions are meant to support a conversation with your doctor. They are not instructions to start, stop, or change any medicine or supplement on your own.

Worth sending to someone who reads labels with you.

---

Written by The Novera Team. Last reviewed: 2026-09-08.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.