What Is Mycelium, and Why Does It Matter in Supplements?

Mycelium is the thread-like network a fungus grows before, and alongside, the mushroom you can see. It is the living body of the fungus, mostly hidden in soil, wood or another growing medium.

This guide explains what mycelium is, how it relates to the fruiting body, how supplement makers grow it and why the growing medium can change what ends up in the capsule or powder you buy.

What Is Mycelium?

Mycelium is the vegetative part of a fungus, a mass of fine branching threads called hyphae that absorb nutrients from their surroundings. If a mushroom is the fruit, mycelium is closer to the plant that produces it.

Each hypha is a tube only a few cells wide. Together, millions of them form a white or cream web that grows through soil, fallen logs, leaf litter or a cultivated substrate. As it grows, mycelium releases enzymes that break down organic matter, then absorbs the nutrients that are released. The mycelium entry on Wikipedia gives a clear summary of this structure.

Mycelium does important ecological work. Many fungi decompose wood and plant material, returning nutrients to the soil, and mycorrhizal fungi form partnerships with plant roots. Mycelium is also used well beyond supplements, from packaging and building materials to food. Researchers have even described mycelium as a nutrient-dense food for future protein supply.

One point often confuses people: mycelium is not mould in the everyday sense, although moulds are fungi with their own hyphae. Edible and functional mushroom mycelium is a separate organism from household mould.

Mycelium vs Fruiting Body: How They Relate

The fruiting body is the reproductive structure that mycelium produces when conditions are right, and it is the part we call a mushroom. Both are the same organism at different stages.

• Spores land on a suitable material and germinate into hyphae.
• Mycelium spreads through the material, feeding and growing.
• Primordia form when temperature, humidity, light and fresh air shift.
• Fruiting bodies mature and release spores, and the cycle repeats.

Because they are different structures, mycelium and fruiting bodies do not have identical compositions. That is the core reason the part used matters on a supplement label. For Lion's Mane (Hericium erinaceus), the fruiting body is the shaggy white mushroom known for culinary use, and it is often researched for its polysaccharides and hericenones. Mycelium is more associated with a different compound group, the erinacines.

How Mycelium Is Grown for Supplements

Most mycelium supplements are made by growing mycelium on sterilised grain, such as oats, rice or sorghum, then drying and milling the whole mass. This is sometimes called myceliated grain or mycelium on grain.

Growing on grain is fast and efficient, which is why it is common. The catch is that mycelium cannot be fully separated from the grain it grew on. When the batch is milled, the remaining grain is milled with it, so the finished powder can contain a meaningful share of the original substrate.

Grain is rich in starch, and starch is an alpha-glucan. On a label or test report that only shows "total polysaccharides", starch can be counted alongside beta-glucans, which makes the number look higher than the beta-glucan content alone. A separate beta-glucan result, tested by a named lab, gives a clearer picture. Mycelium can also be grown in liquid culture, which avoids grain, although that method is less common in consumer products.

Fruiting body products take a different route. The mushrooms are grown on a substrate, then the fruiting bodies are harvested and processed on their own, leaving the growing medium behind.

Why Mycelium Matters When You Buy

Knowing whether a product uses mycelium, fruiting body or both helps you understand what you are paying for. Neither label is automatically wrong, but they are not interchangeable.

• Part used: look for "fruiting body", "mycelium" or "mycelium on grain" stated clearly.
• Fillers: check whether grain, starch or carriers are listed.
• Beta-glucans vs polysaccharides: a specific beta-glucan figure is more useful than a broad polysaccharide claim.
• Testing: a dated lab report shows the numbers were measured.

Suppliers and brands weigh these trade-offs in more detail when they compare fruiting body and mycelium Lion's Mane, including which compounds each may contain. The meaning of a 10:1 fruiting body label is worth understanding too.

Where Xotic Lion's Mane Fits

Xotic Mushrooms uses 100% Lion's Mane fruiting body extract, with no added starch, grain, mycelium or fillers. The mushrooms are grown in Thomastown, Victoria, Australia, on Tasmanian oak hardwood sawdust and Australian soya husk.

Fruiting bodies are harvested, freeze-dried and processed into a 10:1 extract using hot water and ethanol dual extraction. The product is vegan, gluten free and non-GMO, with no caffeine. A tested extract powder blend with 1% BioPerine recorded 32.2% beta-glucans (Symbio S2162602 [R01], 13 May 2026), a sample-specific result rather than a guarantee for every product. Reports from AEGIC and RMIT University researchers are on the Xotic lab results page.

You can choose Lion's Mane extract powder, with a 1 g serve on the label, or Lion's Mane extract capsules, with a 2 x 300 mg serve. Both contain the same extract, and the powder is cheaper per serve. Xotic is Australian-grown and ships its Lion's Mane extract powder and capsules internationally, including to the US, UK, Canada and Singapore.

Building a Mushroom Product for Your Brand?

For businesses, the part used becomes a specification question. Ask any supplier to confirm fruiting body or mycelium, the substrate, extraction method and ratio, and to provide a batch COA with separate beta-glucan and starch results, heavy metals and microbial testing. Confirm MOQ, samples and lead times early.

Xotic offers white and private label Lion's Mane. White label places our established powder or capsules under your brand, while private label covers your own blend, formulation or packaging, usually with higher MOQs and longer lead times. Bulk extract comes in 1 kg and 5 kg.

Final Thoughts on Mycelium

Mycelium is the hidden network of a fungus, and the fruiting body is the mushroom it produces. Both are real parts of the organism.

In supplements, the part used and the growing medium shape the label. Try Xotic fruiting body extract as powder or capsules, and brands can ask about white or private label supply.

FAQs

1. What is mycelium in simple terms?

Mycelium is the root-like network of a fungus. It is made of fine threads called hyphae that grow through soil, wood or another material, breaking down organic matter and absorbing nutrients. The mushroom you see above ground is the fruiting body, which the mycelium produces when growing conditions are right.

2. Is mycelium the same as a mushroom?

Not quite. Mycelium and the mushroom are the same organism, but different structures. Mycelium is the vegetative network that feeds and grows, while the mushroom, or fruiting body, is the reproductive part that releases spores. Their compositions differ, which is why supplement labels should state which part was used.

3. Is mycelium the same as mould?

Mycelium is a general term for the thread network of any fungus, and moulds are fungi too, so both have hyphae. In everyday language, though, mould means fungi growing on food or damp surfaces. The mycelium used for edible and functional mushrooms comes from cultivated mushroom species, not household mould.

4. Why can mycelium supplements contain starch?

Many mycelium supplements are grown on sterilised grain such as oats or rice. The mycelium cannot be fully separated from the grain, so the whole mass is dried and milled together. Grain is high in starch, an alpha-glucan, which can raise a total polysaccharide figure without adding beta-glucans.

5. Does Xotic Lion's Mane contain mycelium?

No. Xotic Lion's Mane is a 100% fruiting body extract with no added starch, grain, mycelium or fillers. The fruiting bodies are grown on Tasmanian oak hardwood sawdust and Australian soya husk in Victoria, Australia, then harvested, freeze-dried and processed into a 10:1 extract using hot water and ethanol dual extraction.

6. Is mycelium better or worse than fruiting body?

Neither is simply better. They are different parts with different compositions, and grain-grown mycelium can include substrate starch. What matters is that the label states the part used clearly and the product has dated lab testing, ideally with a separate beta-glucan result, so you know what you are buying.