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Glossary

What is mycelium in mushroom supplements?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Mycelium is the body of a fungus: a network of fine threads, called hyphae, that grows through its food source, such as wood, sawdust or grain. Mushrooms, the fruiting bodies, grow from it. Supplements labeled mycelium are made from this network, often grown on grain, and that grain can end up in the powder.1,2,3

Key facts

  • MeSH defines mycelium as the body of a fungus, made up of hyphae.1
  • A 2025 analysis of chaga products found that those made from mycelium fermented on grain were rich in starch, unlike the wild chaga growth, which contained none.3
  • The mycelium and fruiting bodies of one fungus can differ in composition, and growing conditions change both.4
  • Laboratories can measure beta-glucan separately from starch-type alpha-glucan in mushroom and mycelial products.5

Where mycelium fits

In shiitake cultivation, the mycelium first spreads through a sawdust log. Later, under the right conditions, it forms knots of hyphae that grow into mushrooms, and those release spores. The mycelium is the body of the fungus; the mushroom is the part that produces spores.1,2

Mycelium grown on grain

Some mycelium products are grown on grain, and the grain stays in the finished powder. In the 2025 chaga study, products made from mycelium fermented on grain were starch rich, while the wild chaga growth contained no starch. The study's authors work for a company that sells chaga supplements, which is worth knowing when weighing it.3

This is why some laboratories measure beta-glucans and starch-type alpha-glucans separately: a figure for total glucan can include starch that came from the grain.5

Reading a mushroom label

  • Part: fruiting body, mycelium or both. FDA requires botanicals, which include fungi, to name the part used.6
  • Substrate: if the label mentions grain, such as mycelium on grain, the grain is part of the powder you take.3
  • Extract or powder: an extract is made with a solvent and concentrates some compounds, while a powder is the dried material.7

Questions people ask

Is mycelium the same as a mushroom?

Not quite. The mushroom is the fruiting body, the spore-bearing part. The mycelium is the network of hyphae it grows from. Both come from the same organism but differ in composition.1,4,8

What is mycelium powder?

Dried and milled mycelium. If it was grown on grain, the powder can include that grain as well, which made such products rich in starch in a 2025 chaga study.3

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Sources

  1. Medical Subject Headings, U.S. National Library of Medicine. Mycelium, descriptor D025282. Opened 2026-10-07.
  2. Song X, Shang X, Zhang M, et al. Cultivation methods and biology of Lentinula edodes. Appl Microbiol Biotechnol. 2025;109(1):63. Opened 2026-10-07.
  3. Windsor C, Kreynes AE, Chilton JS, et al. Comparative Study of Chaga (Inonotus obliquus) Dietary Supplements Using Complementary Analytical Techniques. Int J Mol Sci. 2025;26(7):2970. Opened 2026-10-07.
  4. Jędrejko K, Kała K, Sułkowska-Ziaja K, et al. Cordyceps militaris: Fruiting Bodies, Mycelium, and Supplements: Valuable Component of Daily Diet. Antioxidants (Basel). 2022;11(10):1861. Opened 2026-10-07.
  5. McCleary BV, Draga A. Measurement of β-Glucan in Mushrooms and Mycelial Products. J AOAC Int. 2016;99(2):364-373. Opened 2026-10-07.
  6. Code of Federal Regulations, Title 21, Section 101.4: Food; designation of ingredients. eCFR, current as of October 2026. Opened 2026-10-07.
  7. Monagas M, Brendler T, Brinckmann J, et al. Understanding plant to extract ratios in botanical extracts. Front Pharmacol. 2022;13:981978. Opened 2026-10-07.
  8. Medical Subject Headings, U.S. National Library of Medicine. Fruiting Bodies, Fungal, descriptor D048690. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.