How Mushrooms Are Grown and Processed for Supplements
A plain overview of how mushrooms become supplements: cultivated or wild source, fruiting body, mycelium or mycelium on grain, processing, and why the starting material matters.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
A mushroom supplement can start from very different materials, and the label does not always make the difference obvious. This page explains the general steps in plain language. It is not a guide to growing or making anything at home, and it does not describe how to prepare a product.
Where the material comes from
Many mushrooms in commerce are cultivated on substrates, which are the materials the fungus feeds on. For example, studies of oyster mushroom (Pleurotus ostreatus) cultivation describe substrates such as straw, corn residues and rice husks. [1] Some medicinal fungi are also taken from the wild. One cancer center notes that the natural reserves of chaga (Inonotus obliquus) have nearly been exhausted and that scientists are seeking cultivated substitutes. [2] Wild harvesting and conservation are covered in Wild Harvest, Conservation and Sustainability of Medicinal Fungi.
Three different starting materials
| Starting material | What it is | Why it matters |
|---|---|---|
| Fruiting body | The visible mushroom, such as a cap and stem or a conk. | Most food use is of fruiting bodies. A result for the fruiting body should not be assumed for another material. |
| Mycelium | The threadlike network of the fungus that grows through its substrate. | Mycelium and fruiting bodies are not the same material. A review notes that active compounds are found in fruit bodies, cultured mycelia and cultured broth. [3] |
| Mycelium grown on grain | Mycelium that has colonized a grain or similar substrate. Laboratory work shows that mushroom-producing fungi can ferment and colonize cereal and legume substrates. [4] | The grain may remain part of what is sold. See Mycelium Grown on Grain. |
A chaga example shows why this matters. In one analysis, fermented grain products were starch-rich, while authentic chaga conk was not. [5] The authors work for a company that sells chaga supplements, so read the paper as one source with a financial interest, not as a ruling. [5] The chaga conk is itself unusual: according to one cancer center, the conk used medicinally includes wood from the host tree as well as fungal mycelium. [2]
Processing steps
After harvest or fermentation, material may be dried, milled or extracted. A 2017 study notes that processed raw materials, "modified by milling, drying, or extraction", move through a multilevel supply chain before reaching the finished product. [6] Processing can remove the visible features that identify a fungus, and this is particularly difficult for samples containing fungal mycelia. [6] The same study used DNA barcoding, which checks species identity from genetic code rather than appearance, as a possible way to verify identity. [6]
Extraction is its own subject. See Mushroom Extraction Methods and Fruiting Body vs Mycelium.
Who checks what is in the bottle
In the US, FDA is not authorized to approve dietary supplements for safety and effectiveness before they are marketed. [7] A review of "immune health" products reported that popular botanical and functional mushroom products can suffer adulteration with inaccurate labeling, through intentional or unintentional addition of lower grade ingredients. [8] Authenticity, mislabeling and quality control are also named as concerns for chaga products. [5]
What a reader can do:
- Look for the scientific name, the part used and whether the product is fruiting body, mycelium or grain-based.
- Ask a pharmacist about the product and your medicines.
- Read How to Read a Mushroom Supplement Label and Quality Testing and Certifications to learn what testing can and cannot show.
Frequently asked questions
Is a mushroom supplement made from the whole mushroom?
Not always. It may be made from fruiting body, mycelium or mycelium grown on grain, and these are different materials. [3][5]
What is mycelium on grain?
It is mycelium grown on a grain-type substrate. In a chaga analysis, fermented grain products were starch-rich and authentic chaga conk was not. [5] See Mycelium Grown on Grain.
Can a lab tell which mushroom is in a product?
Sometimes. DNA barcoding was used to check the identity of 33 fungal samples, and in most cases it could be sequenced from powdered mycelium, grocery mushrooms and supplement capsules. [6] The study's title asks whether it is a partial solution for product certification. [6]
Does FDA approve mushroom supplements before sale?
FDA is not authorized to approve dietary supplements for safety and effectiveness before they are marketed. [7]
Are cultivated mushrooms better than wild ones?
Proper evidence not found for human outcomes. We searched PubMed for comparisons of wild and cultivated medicinal mushrooms and found only laboratory chemistry. In one such study of Ganoderma lucidum extracts, ganoderic acid and ergosterol levels were higher in cultivated than wild samples, while one enzyme test was higher in wild samples. [10] That says nothing about benefit in people.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
Supplements can interact with medicines or carry risks if you have certain medical conditions or are about to have surgery, so talk with a clinician and tell your surgical team about every supplement. [9] See How Interactions Work. Never use a wild-picked mushroom on the strength of a photo or an app; call Poison Help at 1-800-222-1222 (US) after a possible poisoning.
References
- Agri-food wastes as substrates for oyster mushroom (Pleurotus ostreatus) cultivation and their agricultural potential. Sci Rep. 2025. PubMed 41315478. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Chaga Mushroom. Read 2026-10-23.
- Wasser SP. Medicinal mushrooms in human clinical studies. Part I. Anticancer, oncoimmunological, and immunomodulatory activities: a review. Int J Med Mushrooms. 2017. PubMed 28605319. Read 2026-10-23.
- The potential of mycelium from mushroom-producing fungi in alternative protein production: a focus on fungal growth, metabolism, and nutrition. Curr Res Food Sci. 2025. PubMed 41551172. Read 2026-10-23.
- 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. Authors are employed by a company that sells chaga supplements, as the paper states. PubMed 40243601. Read 2026-10-23.
- Raja HA, Baker TR, Little JG, Oberlies NH. DNA barcoding for identification of consumer-relevant mushrooms: a partial solution for product certification? Food Chem. 2017. PubMed 27507489. Read 2026-10-23.
- U.S. Food and Drug Administration. Information for Consumers on Using Dietary Supplements. Read 2026-10-23.
- You H, Abraham EJ, Mulligan J, et al. Label compliance for ingredient verification: regulations, approaches, and trends for testing botanical products marketed for "immune health" in the United States. Crit Rev Food Sci Nutr. 2024. PubMed 36123797. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Read 2026-10-23.
- Supercritical carbon-oxide extracts from cultivated and wild-grown Ganoderma lucidum mushroom: differences in ergosterol and ganoderic acids content. Nat Prod Res. 2024. PubMed 36744699. Read 2026-10-23.