Sourcing & Quality · 5 min read
Why Fruiting Body Matters (and Why Mycelium-on-Grain Doesn't)
Most supplements on the shelf are mycelium grown on grain, which means you're paying for starch. Here's how to tell the difference.
By Scott Burgess, ND · Naturopathic Doctor and Formulator, Rhizomatic Gardens
This distinction does not get enough air time, and the supplement industry has spent money keeping it quiet.
A mushroom has a life cycle. The part you recognize, the cap and stem, is the fruiting body. It's what the organism produces to reproduce, and it's where medicinal compounds concentrate: beta-glucans, triterpenes, polysaccharides, hericenones. The mycelium is the root-like network that comes before it. Both have some biological activity. But they are not equivalent, and they are not interchangeable on a label.
The problem is how mycelium is commercially produced. Manufacturers grow mycelium on a grain substrate, typically oats or brown rice, in large batches. When the growth cycle ends, the mycelium is inseparable from the grain it colonized. The entire mixture gets dried, ground, and encapsulated. Analysis of these products routinely shows 30 to 60 percent starch by weight. A 2017 study published in International Journal of Medicinal Mushrooms tested commercial mycelium-on-grain products and found beta-glucan content as low as 1.1 percent, compared to 14 to 40 percent in dried fruiting body extracts.
You are paying for starch.
How to tell the difference on a label: if it says "mycelium" and does not specify extraction or beta-glucan percentage, assume it is mycelium-on-grain. If it says "fruiting body extract" with a beta-glucan or polysaccharide percentage listed, it has been through aqueous or dual extraction, which is required to break down the chitin cell walls and release the active compounds into bioavailable form.
Unextracted fruiting body is better than mycelium-on-grain. Extracted fruiting body is better than unextracted. Hot water extraction pulls the polysaccharides. Dual extraction (hot water plus ethanol) also pulls the fat-soluble triterpenes critical for Reishi's adaptogenic and immune properties.
The four questions to ask before buying any mushroom supplement: Is this fruiting body or mycelium? Is it extracted? What is the beta-glucan percentage? Does the COA show starch content?
If a company cannot answer those four questions directly, that answer is your answer.
† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any new supplement, especially if you are pregnant, nursing, or taking medication.