Functional mushroom products reached approximately $1.9 billion in 2025 and are projected to exceed $2.2 billion by the end of 2026, driven by mushroom coffee, energy drinks, and gummies. The regulatory framework governing that market has not kept pace. The FDA has not issued guidance specifically for functional mushrooms, and silence is not a green light. What the agency has said — through warning letters, GRAS determinations, and enforcement actions — defines the actual compliance picture for manufacturers and retailers operating in this space.

What the FDA Has Said

The clearest FDA communication in the functional mushroom space is what the agency has done, not what it has written.

In 2021, the FDA issued a warning letter to an online supplement company selling lion's mane, maitake, reishi, and cordyceps products, finding that the claims on their website — including "helps to lower cholesterol," "anti-inflammatory," and cancer-fighting language — made the products unapproved new drugs under section 201(p) of the FD&C Act. The mushroom ingredients themselves were not the problem. The claims were. The FDA issued a similar warning in 2023 to another botanical supplement company selling lion's mane, chaga, and reishi products with claims including "lowering cholesterol, blood sugar and blood pressure" and cholesterol-reducing language for reishi.

The pattern holds across both actions: structure-function claims like "supports immune health" or "helps maintain focus" are permissible under DSHEA. Claims that describe the treatment, prevention, or mitigation of a specific disease or condition cross into drug territory and require FDA approval, which is not available for these products.

On Amanita muscaria specifically, the FDA was direct. In December 2024, the FDA determined that Amanita muscaria, its extracts, and certain constituents — muscimol, ibotenic acid, and muscarine — do not meet the GRAS standard and are unapproved food additives. That ruling drew a hard line between Amanita products marketed as "legal psychedelics" and conventional functional mushrooms like lion's mane and reishi, which remain legal for sale as dietary supplements.

What the FDA Has Not Said

There is no FDA guidance document, final rule, or regulatory framework specific to functional mushrooms. Lion's mane, reishi, chaga, cordyceps, and turkey tail operate under the general dietary supplement rules established by DSHEA — the same framework that governs vitamins, minerals, and herbal products. The FDA does not pre-approve these products for safety or efficacy before they reach market.

The gap that catches brands most often is the food and beverage channel. GRAS status for functional mushrooms is ingredient-specific and depends on identity, manufacturing, dose, and use in specific food categories — it is not automatic. A mushroom ingredient that is legally sold as a capsule supplement is not automatically cleared for use in a ready-to-drink beverage, a gummy, or a protein bar. Chaga, reishi, and cordyceps are among the ingredients that are not generally recognized as safe for use in conventional foods and beverages, yet they appear widely in those formats anyway.

FDA rarely asks for GRAS confirmation from brand owners, which signals to many companies that they can push the envelope with ingredients that lack previous GRAS evidence. That posture has a ceiling. Brands expanding into food and beverage formats without a defensible GRAS position are carrying regulatory exposure that grows with market visibility.

The Labeling Problem the Industry Created

A separate compliance issue lies at the ingredient-identity level. Nammex, a major mushroom ingredient supplier, petitioned the FDA to require that products containing fungi properly identify the fungal part — whether fruiting body or mycelium — and disclose any substrate on which the ingredient is grown. The petition cites concerns about deception and fraud. Currently, the FDA's compliance policy guide uses "mushroom mycelium" to describe any fungi product, which obscures meaningful differences in compound profile and potency.

For manufacturers, this matters because claims built around beta-glucan content, hericenones, or other bioactive compounds need to accurately reflect what the product actually contains. A Certificate of Analysis that verifies species identity, part used, and active compound concentrations is not just a quality tool — it is the documentation that makes a structure-function claim defensible.

What Businesses Should Be Doing

Functional mushroom companies operating only in the supplement channel have a cleaner compliance path than those entering the food and beverage channel. For supplement products, the requirements are clear: compliant structure-function claims, DSHEA disclaimer, GMP manufacturing, and batch-level COA documentation. For food and beverage applications, companies need a formal GRAS assessment for each ingredient under its intended conditions of use before launch.

Brands are as likely to face challenges from commercial retailers as from the FDA itself — major natural retailers have become aggressive about ingredient permissibility and require documentation that the agency rarely demands up front.

Contact Qredible today to learn how our quality management solutions help functional mushroom and botanical supplement businesses implement batch-level Certificate of Analysis management, maintain defensible structure-function claim documentation, and build the ingredient verification infrastructure necessary to meet both regulatory and retailer requirements in a market that is drawing increasing scrutiny.