Key takeaways
- The fruiting body is the visible mushroom; the mycelium is the thread-like network it grows from.
- Mycelium is often grown on grain, and the grain frequently ends up in the product.
- Grain starch (alpha-glucans) can inflate glucan test results if not separated from beta-glucans.
- Fruiting bodies and mycelium can contain different compounds; neither is simply a lesser version.
- Check labels for the part used, and for any grain or substrate.
Of all the questions to ask about a mushroom product, “which part of the mushroom is it made from?” is one of the most revealing. The answer is usually either the fruiting body, the mycelium, or a mixture. They are parts of the same organism, but they are not the same thing, and products made from each can differ considerably.
Two parts of one organism
A fungus spends most of its life as mycelium: a web of microscopic threads, called hyphae, spreading through wood, soil or another food source. When conditions are right, the mycelium produces a fruiting body, the structure we recognise as a mushroom, which releases spores to start the cycle again. Our article What Is a Fruiting Body? explains the life cycle in more detail.
How each is produced commercially
Fruiting bodies are grown on logs, sawdust or other substrates, then harvested, dried and processed. The mushroom is picked away from what it grew on.
Mycelium is often grown on sterilised grain, such as rice or oats. Because the mycelium grows through the grain and can’t easily be separated from it, the whole mass is frequently dried and ground together. The resulting product, sometimes called myceliated grain, can contain a substantial proportion of grain.
Mycelium can also be grown in liquid culture, which avoids the grain issue, but this is less common in consumer products.
Why the grain matters
Grain is mostly starch. Starch is made of alpha-glucans, which are different from the beta-glucans found in fungal cell walls. When a mycelium-on-grain product is tested for total glucans without distinguishing between the two, the starch can make the figures look higher than the mushroom content alone would justify. Specific testing methods can separate beta-glucans from alpha-glucans; our articles on mycelium on grain and beta-glucan testing explain how.
Do fruiting bodies and mycelium contain different compounds?
Sometimes, yes. The two stages of a fungus don’t always produce the same compounds in the same amounts. Lion’s Mane is a well-known example: hericenones are associated with the fruiting body, while erinacines are found mainly in the mycelium. To be even-handed, this means mycelium isn’t simply an inferior version of the mushroom; it is a different material. What matters is that a product is honest about which it contains, and how much of it is actually fungus.
A special case: chaga
Chaga doesn’t fit neatly into either category. What is harvested from birch trees is a dense, sterile mass rather than a true fruiting body. That’s why you’ll see it described simply as “chaga”. Read Why Chaga Is Not Technically a Mushroom for the full story.
How to tell what you’re buying
- Look for “fruiting body” stated clearly on the label.
- Watch for “mycelium”, “myceliated” or “mycelial biomass”, and check whether a grain or substrate is listed.
- Be wary of vague terms such as “full spectrum” or “whole mushroom” without an explanation.
- Ask for test results that separate beta-glucans from starch where relevant.
Why we use fruiting bodies
Spore & Bloom tinctures are made from UK-grown fruiting bodies (and, in the case of chaga, wild-harvested chaga from Finland). We don’t use grain-grown mycelium. For us, it’s the most straightforward way to know that what goes into the bottle is the mushroom itself. You can read more in Why We Focus on Fruiting Bodies, or explore our mushroom tinctures.