Robin Gurney, managing director at Estonia-based premium organic mushroom extract and supplement manufacturer Musheez, has reviewed the current body of evidence behind popular mushroom species Lion’s Mane (Hericium erinaceus) and Reishi (Ganoderma lucidum / Lingzhi), finding significant reporting gaps related to intervention description, material characterization, and metabolite profiling.
“The body of evidence contains useful human studies. The issue is that the evidence is often less transferable than the market assumes,” he told NutraIngredients.
He said many studies reviewed report the amount of ingredient administered but not the identity and characterization of the intervention.
“This matters because medicinal mushroom interventions are not uniform entities,” he explained.
He explained that even within one species, materials may differ substantially by fungal part, species strain, cultivation conditions, harvest maturity, post-harvest handling, extraction route, carrier content, batch consistency, and chemical profile.
“As a result, nominal daily dose alone is often a weak basis for translation to formulation practice or real-world use,” he said.
“The industry needs to be more careful about turning one study’s dose into a general recommendation for a completely different commercial ingredient,” he argued. “Brands should ask suppliers whether their ingredient is genuinely comparable with the material used in the study they are citing.”
The paper proposes an eight-part reporting framework covering fungal part, species identity, cultivation, harvest and handling, extraction and processing, carriers, batch integrity, and analytical/metabolite characterization.
Gurney added: “We are calling for better research reporting and better discipline in how studies are interpreted commercially.“
Dosage guide not possible
Gurney’s review, published online in the open-access preprint platform Zenodo and accepted for post presentation at IMMC13 (the International Medicinal Mushroom Conference), was borne out of a desire to produce an evidence-based dosage guide for functional mushrooms.
However, Gurney said in starting that research he realized the body of evidence was not complete enough to be able to achieve his aim and instead reverted to completing a review of the gaps within the human studies currently available.
Across the reviewed literature of studies of the two popular mushroom varieties (with a primary focus on fruiting-body-derived interventions), Lion’s Mane studies showed a more clustered dosage history for fruiting-body-based interventions, whereas Reishi studies spanned a broader and more heterogeneous range of nominal doses and preparation types.
Key details missed in several studies included a range of crucial details: fungal part, species identity and identity verification, cultivation substrate and conditions, harvest maturity and post-harvest handling, extraction and processing method, carrier and exipient content, batch identity and consistency, and compounds of interest or metabolite profile.
A prominent issue in botanical research
Bill Chioffi, COO at organic mushroom extract supplier Nammex, said this review puts into writing a prominent issue in the mushroom sector.
“This paper explains quite clearly something people in this industry have quietly known for years: material without characterization on a label tells you almost nothing about what was actually tested,” he told NI. “Two studies can both say ’500mg/day’ and still be describing materially different interventions.”
Nammex’s founder Jeff Chilton’s illustrated the issue in a 2015 HerbalGram article. He noted characterization failure can have a direct consequence for formulators and consumers making choices based on a name and a dose number that poorly describes the material.
“Most manufacturers and brands aren’t trying to sell an underpowered product; they’re sourcing against a spec sheet and a dose that looks equivalent to what’s cited in the literature, without the analytical or financial means to confirm the material matches,” added Chioffi.
He added Nammex reported this in its own comparative study of commercial Chaga products, where several samples were found to be nothing but fermented grain biomass, which was low in the marker triterpenoids and phenolics and high in starch.
“That’s not a labeling technicality; it’s the product not containing what the research says should be there,” Chioffi said.
“It’s why we’ve been pushing on reference materials and standards work, including our contribution to AOAC’s Reishi Standards Working Group and the authenticated Hericium Erinaceus reference materials we presented at ICSB this year.”
He added that Gurney’s reporting framework gives researchers a checklist for human studies, “so the next generation of research gives formulators something they can actually build a product against”.
Stefan Gafner, chief scientific officer at the American Botanical Council (ABC), agreed the review highlights an important issue within botanical studies.
“In general, a thorough chemical characterization needs to be part of a clinical study, and it is really disappointing to see that many manuscripts still fall short of this even today,” he told NI.
He added that reishi is especially challenging due to the nomenclatural confusion and the unclear taxonomic status.
“I think there are still some studies that are carried out by medical professionals who may not have expertise in chemical analysis and hence do not exactly know how a thorough product characterization looks like.”
