I’ve written extensively about the health benefits of functional mushrooms, and I’ve repeatedly highlighted why including the mycelium of fungi matters. I also get a lot of questions on the matter. Let’s focus on that for a moment.
When most people think of mushrooms, they think of the fruiting body. That’s the visible structure that sprouts above the surface and releases spores so the fungus can spread i.e. the sexual organ. It’s the part you see in grocery stores when you buy mushrooms, it is what you buy. But the fruiting body is only a fraction of the organism. Beneath it is the mycelium: a sprawling root-like network that communicates with surrounding fungi, absorbs nutrients, breaks down surrounding material, and produces many biologically active compounds. However, unlike roots mycelium are very small, almost hair-like.
Our cells (eukaryotic) take in food and digest it internally. We have organelles in every cell that contain digestive enzymes, almost like little stomachs in every cell. Fungi work differently. They secrete digestive enzymes outward from the mycelium, breaking material down externally before absorbing nutrients back in. In many ways, the mycelium is the true body of the fungus.
Most supplement companies focus exclusively on fruiting bodies because they are easier to standardize and process. One challenge with mycelium is separation from the growth substrate. If mushrooms are grown on grain or sawdust, poorly processed products can contain leftover filler material. Because of this, many companies rely heavily on beta-glucan measurements from fruiting bodies to define “purity” and quality.
Beta-glucans absolutely matter. They are important structural polysaccharides found in fungal cell walls and are associated with immune-supportive effects. But focusing only on beta-glucans ignores an important reality: some of the most interesting and well-studied mushroom compounds are primarily associated with the mycelium, and are not easily quantified.
Let’s look at the research.
Lion’s Mane
Lion’s mane is most known for supporting brain health, memory, focus, and nerve regeneration. One of the most studied compounds associated with these effects is erinacine A, a molecule shown to stimulate nerve growth factor (NGF) production. Erinacine A is only found in the mycelium of lion’s mane rather than the fruiting body (https://pubmed.ncbi.nlm.nih.gov/32581767/).
Turkey Tail
Turkey tail is well known for immune and gut support, but it has also been extensively studied for its anti-cancer properties. One of its best-known compounds is PSK (polysaccharide-K, or Krestin), which has been used clinically in parts of Asia as an adjunct to cancer treatment. PSK is derived from cultured turkey tail mycelium. Again, this potent compound is only found in mycelium. (https://pubmed.ncbi.nlm.nih.gov/12168863/)
Reishi
Reishi has long been associated with calmness and sleep support. A recent study showed that reishi mycelium promoted natural sleep through serotonin-related signaling pathways. In that study, the researchers specifically utilized reishi mycelium also known as GLAA rather than fruiting bodies (https://pubmed.ncbi.nlm.nih.gov/34211003/).
Chaga
Chaga is unique because the large black structure commonly harvested from birch trees is not a traditional fruiting body at all. It is primarily a hardened mycelial mass known as a sclerotium. Yes, I know that sounds dirty. In many ways, chaga itself reinforces the idea that mycelium is biologically important. Research has shown that this mycelium is able to lower blood sugar and promote pancreatic health (PMID: 39523023).
Cordyceps
Cordyceps may be one of the clearest examples of why mycelium matters. One of its most studied compounds, cordycepin (3’-deoxyadenosine), is an adenosine analog and heavily associated with cultured cordyceps mycelium. Cordycepin has been investigated for anti-inflammatory, antioxidant, metabolic, and anti-cancer effects, including interactions with immune signaling and the tumor microenvironment (PMCID: PMC11274779). In fact, much of the cordyceps research and commercial production relies on cultivated mycelium rather than wild fruiting bodies because the mycelial stage can produce significant levels of cordycepin.
Maitake
Maitake is often discussed in terms of beta-glucans and immune support, but many experimental preparations used in research often contain cultured fungal biomass that includes mycelial material rather than isolated fruiting bodies alone. In studies examining neuroprotection and Alzheimer’s disease models, maitake-derived mycelial preparations reduced amyloid plaque accumulation and improved cognitive performance (https://pmc.ncbi.nlm.nih.gov/articles/PMC9075749/).
Across functional mushrooms, the mycelium is not simply a root-like support system. It is a biologically active part of the organism capable of producing unique and clinically relevant compounds. A company that doesn’t get it means you don’t get it. Here at Brain Wave, we got you covered.
Until next time,
Dr. Andy