Fruiting body vs. mycelium
The fruiting body is the part most people picture as a mushroom: the cap and stem that grow above ground. The mycelium is the root-like network the fungus grows from.
Commercially, mycelium is often grown on a grain such as rice or oats, and the finished powder can include that grain. That matters because grain is mostly starch. Labels may list the fruiting body, the mycelium, or both. The ingredient line should tell you which.
The two parts can also contain different compounds. In lion's mane, for example, researchers have isolated compounds called hericenones from the fruiting body and erinacines from the mycelium.
Polysaccharides are not all beta-glucans
"Polysaccharide" simply means a long chain of sugar units. Starch is a polysaccharide. So are the beta-glucans that most mushroom research focuses on. A test for total polysaccharides cannot tell them apart.
Researchers at Megazyme developed an enzyme-based method that measures alpha-glucans (starch and glycogen) separately and calculates beta-glucan from the difference. In their 2016 study, most mushroom fruiting bodies contained under 4% alpha-glucan, while in grain-grown mycelium products starch was often the main glucan present. A 2017 study of 39 mushroom species called the Megazyme approach the most reliable of the methods it reviewed.
| Total polysaccharides | Beta-glucans | |
|---|---|---|
| What it counts | Many kinds of carbohydrate chains, including starch (alpha-glucans) | Beta-glucans specifically |
| Common test | Colorimetric methods read by UV-Vis | Enzyme-based assays, such as the Megazyme method |
| Affected by grain starch? | Yes; starch is counted | Starch is measured separately and excluded |
| What it tells you | How much carbohydrate polymer is present | How much of the compound mushroom research usually focuses on |
What the ranges look like
Using the enzyme method, the 2017 study measured beta-glucan in mushroom fruiting bodies from roughly 8 to 61 grams per 100 grams of dry mass, depending on species. Lion's mane was not among the species tested.
Testing published by Nammex, a mushroom-extract supplier with a commercial interest in fruiting-body products, reported that whole mushrooms were low in starch, while mycelium grown on grain averaged about 35% to 40% starch and often 10% or less beta-glucan. We cite it because the pattern matches the peer-reviewed work, but it comes from a seller, not an independent lab.
Questions to ask of any mushroom label
Few labels answer all five. When one is missing, the honest reading is that the information is unknown, not that it is good or bad.
| Check | Why it matters |
|---|---|
| Species name (for example, Hericium erinaceus) | Confirms which mushroom is in the product |
| Fruiting body, mycelium, or both | Grain-grown mycelium can add starch |
| Polysaccharides or beta-glucans | Polysaccharides can include starch; beta-glucans are specific |
| Test method named | Colorimetric and enzyme methods measure different things |
| Batch document available | A label states a target; a lot record shows a measured result |
How we describe our own product
DECLARED Lion's Mane contains 1,000 mg of organic lion's mane fruiting body and mycelium per two-capsule serving. The label states it is standardized to 40% polysaccharides, or 400 mg.
The batch report we reviewed measured 401.78 mg of total polysaccharides per serving by UV-Vis. That is a total polysaccharide result, not a beta-glucan result, and it does not separate out starch. Without a beta-glucan test on file, we do not describe this product's polysaccharides as beta-glucans.
What a label cannot settle
Neither a polysaccharide nor a beta-glucan figure tells you what a product will do for you. Human research on lion's mane is early, with a small number of short trials. A label can tell you what is in the capsule and how it was measured. It cannot tell you more than that.
Sources
- McCleary BV, Draga A. Measurement of β-glucan in mushrooms and mycelial products. J AOAC Int, 2016
- Sari M et al. Screening of beta-glucan contents in commercially cultivated and wild growing mushrooms. Food Chemistry, 2017
- Ma BJ et al. Hericenones and erinacines: stimulators of nerve growth factor (NGF) biosynthesis in Hericium erinaceus. Mycology, 2010
- Nammex — Redefining Medicinal Mushrooms (supplier white paper)
- Alzheimer's Drug Discovery Foundation — Cognitive Vitality: Lion's Mane
This material is for general educational purposes only and is not medical advice. Consult a qualified healthcare professional about your individual circumstances.