Fruiting Body, Mycelium-on-Grain, and Liquid Fermentation: What's Actually in Your Mushroom Supplement

There's a conversation going around at the moment about mushroom supplements not always containing what people assume, specifically, that a lot of mycelium products on the market are mostly grain starch rather than mushroom. It's a fair point, and it's worth understanding properly rather than dismissing it or overselling it. Here's what's actually in a mushroom supplement depending on how it's made, and why our own range uses two different approaches rather than just one.

The Quick Answer

There are three distinct ways a mushroom supplement can be made, not two. Fruiting body extract concentrates compounds from the visible mushroom itself. Mycelium-on-grain grows mycelium on rice or oats and processes the whole mass, mycelium and grain together, which is where the "it's mostly starch" criticism genuinely applies. Liquid-fermentation mycelium extract grows mycelium in a nutrient-rich liquid instead of on grain, so there's no starch left to dilute it. Most of our range is fruiting body extract. Alchemy, our one mycelium product, is liquid-fermented, not grown on grain.

Fruiting Body Extract

The fruiting body is the part most people picture when they think of a mushroom, the visible cap and stem that grows above the substrate. Fruiting body extract is made by harvesting that part, drying it, and extracting it to concentrate its active compounds, mainly beta-glucans. It's what most of our range, Lion's Mane, Turkey Tail, Reishi, Chaga and Cordyceps, is made from, and it's the approach most premium mushroom brands lean on for good reason: for these mushrooms, it's where the compounds we're after are most concentrated.

Mycelium on Grain: The Real Problem

This is the method the current conversation is actually about, and the criticism is legitimate. Mycelium is grown on a grain substrate, usually rice or oats, and at harvest the entire mass, mycelium and grain together, is dried and powdered as one product rather than separated. Because the grain is never removed, a meaningful share of what ends up in the finished product is grain starch, not mushroom. Testing that only reports a generic "polysaccharide" figure can make this kind of product look more concentrated than it actually is, since starch itself is a polysaccharide.

This is a real quality problem, and it's common, particularly in mycelium products grown at lower cost. But it's a problem with growing mycelium on grain specifically, not with mycelium as a category.

Liquid-Fermentation Mycelium Extract

The third method solves the grain problem differently: it removes the grain entirely. Mycelium is grown in a nutrient-rich liquid culture instead of on a solid substrate, then harvested from that liquid and extracted on its own. There's no starch to separate out because there was never any grain to begin with, so what ends up in the product is concentrated mycelium compounds. This is a more involved and more expensive process than growing on grain, which is part of why it's less common, but it's also why a genuinely liquid-fermented mycelium extract doesn't carry the same criticism mycelium-on-grain does.

Alchemy, our liquid-fermented blend of Shiitake, Maitake, Lion's Mane and Agaricus blazei, is made this way, and it's the same broad approach behind AHCC, a well-known trademarked mycelium extract. We've gone into that comparison in more detail in a separate piece if you want the fuller picture.

Three Methods at a Glance

Why We Use Two of the Three

For most of the mushrooms we work with, fruiting body is simply where the compounds we're after are most concentrated, so that's what we use. But that's not universal, and Alchemy is our clearest example of why. Its mycelium blend of Shiitake, Maitake, Lion's Mane and Agaricus blazei is rich in acetylated alpha-glucans, a compound class concentrated in the mycelium of these mushrooms and not found in anything like the same richness in the fruiting body. For that compound class specifically, mycelium isn't a workaround or a substitute for fruiting body, it's simply where the compound actually is.

That's why we don't treat mycelium as something to avoid altogether. When a compound genuinely concentrates in the mycelium rather than the fruiting body, growing that mycelium properly, in a liquid culture rather than on grain, is the right tool for the job, not a cheaper workaround.

That's why we don't treat mycelium as something to avoid altogether. When a compound genuinely lives in the mycelium rather than the fruiting body, growing that mycelium properly, in a liquid culture rather than on grain, is the right tool for the job, not a cheaper workaround.

Beta-Glucans vs Alpha-Glucans, in Brief

Beta-glucans are the compound class most associated with fruiting body extracts and the marker we test for across our capsule range. Alpha-glucans are a related but distinct compound class, notably acetylated alpha-glucans, associated with liquid-fermented mycelium extracts like Alchemy and AHCC. Both are legitimate quality markers; the one to look for depends on which type of product you're actually holding. A product that only advertises a vague "polysaccharide" percentage, without specifying which glucan class, is the figure worth being sceptical of.

What to Actually Check on Any Label

• Whether a mycelium product is grown on grain or in a liquid culture, since that's the single biggest quality factor
• Whether beta-glucans or alpha-glucans are stated specifically, rather than a generic "polysaccharide" figure
• Whether that figure comes from independent testing or only a formulation target
• Whether the product is genuinely extracted, or just a dried, unextracted powder

These questions tell you far more about mushroom extract quality than whether a product is labelled "fruiting body" or "mycelium" alone.

Where to Start

If you want to see how this plays out across a full range, our mushroom capsules are fruiting body only, dual-extracted, and third-party tested in New Zealand, with results published on our test reports page. If you're curious about the liquid-fermentation side specifically, Alchemy is where we've put that approach into practice, and MyComplete brings six fruiting-body mushrooms together in one daily blend if you'd rather cover more ground at once.

Disclaimer: It is important to consult a health professional before taking supplements if you have a health condition, are taking medication, are pregnant, or nursing.