Mushroom Immune Support: A Plain-English Guide to Shiitake, Maitake and Reishi

If you’re considering a mushroom supplement for immune support, these three are a good place to start. Shiitake and maitake are food mushrooms you may already have cooked with. Reishi is too tough and bitter to eat, so it’s taken as an extract. This guide covers what each one contains, what researchers have studied, how the three compare, and how to read a mushroom label so you know exactly what’s in the capsule.

The short answer: all three contain beta-glucans, a type of fiber in mushroom cell walls that immune cells are built to recognize. Reishi also carries triterpenes, bitter compounds that dissolve in alcohol rather than water. Research on each mushroom has focused on different immune cells, which is why they’re often combined rather than taken alone.

Shiitake is the most familiar of the three, and the only one most people have cooked with. Its best-known beta-glucan is lentinan, named after the mushroom itself. In a randomized trial of shiitake in healthy young adults¹, 52 men and women aged 21 to 41 ate whole dried shiitake every day for four weeks, and researchers compared blood and saliva samples taken before and after. Two groups of T cells multiplied more readily when tested in the lab, one by about 60% and the other roughly twofold, and levels of secretory IgA, an antibody in saliva that forms part of the body’s first line of defense in the mouth and gut, went up.

Maitake grows in large, frilly clusters at the base of oak trees, which is how it earned the name hen of the woods. Its beta-glucans include a fraction researchers call D-fraction, and most maitake research has looked at how it affects the immune cells that act first: macrophages and NK cells. In an animal study of maitake and shiitake extracts², two weeks of oral extract increased macrophage and NK cell activity, and the maitake and shiitake combination gave the strongest response of all the preparations tested, ahead of either mushroom alone.

Reishi is a glossy, woody mushroom that has been used in East Asian traditions for centuries. It is too tough to eat, so it is almost always prepared as an extract. Besides beta-glucans, it carries triterpenes, which do not dissolve in hot water; that is why reishi is often extracted twice, with water and then with alcohol. In a double-blind trial of reishi extract in older women³, participants received a reishi dry extract or a placebo for eight weeks, and researchers found changes in how their T cells responded when stimulated in the lab, with a shift toward a calmer, less inflammatory pattern.

Beta-glucans from fungi have been tested in dozens of human trials. A systematic review of 34 fungal beta-glucan trials⁴ (a study that gathers and assesses every trial on a question) included beta-glucans from shiitake and reishi among its sources. Immune function was the outcome most of those trials measured, and the review recorded no adverse events caused by the beta-glucans themselves.

Combining the three isn’t just tradition. In a laboratory study of a shiitake, reishi and maitake formula⁵, researchers tested nine store-bought mushroom extracts, picked one of each mushroom and combined them. They then compared the blend with each extract on its own, using human immune cells called macrophages. The blend triggered a stronger response than the three extracts would be expected to produce added together, an effect called synergy. The study was done in cells, not people, so it shows how the extracts behave in a lab rather than in the body.

The same three mushrooms are combined in MycoRev Immune, the immune formula from the 3rd Planet mushroom line, which Aduco carries.

For more on how mushrooms interact with the immune system, see our article on the topic.

Mushroom labels vary a lot, and a few details tell you far more than the front of the bottle. Here is what to look for, and what the MycoRev Immune label shows for each.

Every figure in the first three columns comes straight from the Supplement Facts panel of MycoRev Immune; the last column is how 3rd Planet describes each extract. The reishi is the most concentrated extract in the formula, and 3rd Planet describes it as extracted with both alcohol and water, so it carries triterpenes as well as beta-glucans. Aduco’s companion article, what makes MycoRev Immune different, walks through how the formula was put together.

The FDA’s consumer guidance on dietary supplements⁶ advises speaking with a healthcare provider before starting a supplement, especially alongside medicines. Follow the directions on the label or your practitioner’s advice.

MycoRev Immune is the 3rd Planet formula built specifically around immune function. The other formulas in the line pair different mushrooms, and sometimes botanicals, for other goals. MycoRev Tonic, the line’s everyday mushroom foundation, combines chaga, cordyceps and lion’s mane rather than the three immune species.