Emerging & Specialty Mushrooms
2,000+ years
Agarikon is the oldest documented medicinal mushroom in Western history, and in 2026 it became the first fungal species of its kind tested in a randomized human clinical trial for immune support after vaccination.
Saxe et al., BMC Immunol, 2026
~65 CE
earliest written record of medicinal use, in Dioscorides' De Materia Medica
90
participants in the first randomized human trial, published 2026
0
isolated agarikon compounds with a published antiviral potency value
Saxe et al., BMC Immunol, 2026
View as image ↗In 2026, researchers at UC San Diego published a result that barely registered outside specialist circles. A randomized, double-blind, placebo-controlled trial of 90 people found that a mycelium preparation containing agarikon reduced vaccine side effects and preserved antibody responses over six months in participants who had never been exposed to SARS-CoV-2, with 100% trial completion and no adverse events.[1] It was the first randomized clinical trial to test this mushroom in humans.
Most people have never heard of the species being tested. That is partly because it is extraordinarily rare: agarikon (Laricifomes officinalis, still widely published under the name Fomitopsis officinalis) is a large bracket fungus that grows almost exclusively on old-growth conifers and has largely disappeared from its historical European range.[4] It is also one of the oldest recorded medicines in Western history, described by the Greek physician Dioscorides around 65 CE for tuberculosis and respiratory illness — a use that, two thousand years later, turned out to have a chemically interesting parallel.
This article covers the full picture: what agarikon is, where it grows, what makes it biologically active, what the laboratory evidence does and does not show, and what the 2026 clinical trial found. It also corrects several claims that circulate widely in agarikon coverage and do not survive a check against the source papers. Each section links to a dedicated deep-dive for readers who want more detail.
Key Takeaways
- Agarikon's currently accepted scientific name is Laricifomes officinalis, though most research is still published under Fomitopsis officinalis. Both names refer to the same organism. It has no relationship to Agaricus mushrooms such as white button or portobello, despite the similar-sounding name.
- A 2014 review of European ethnobotany found agarikon was one of five polypore species widely used in central European folk medicine, for coughs, rheumatism and related complaints, alongside archaeological evidence of polypore use going back more than 5,000 years. (Grienke et al., J Ethnopharmacol, 2014)
- No isolated, chemically defined compound from agarikon has a published antiviral potency value. The frequently quoted figure — fomitopsin D inhibiting herpes simplex virus at an IC50 of 17 micrograms per millilitre — comes from Fomitopsis feei, a different species, and those compounds have not been shown to occur in agarikon.
- The chlorinated coumarins that genuinely were isolated from agarikon came from an ethanol extract and showed a narrow antimicrobial spectrum, with their lowest MICs against the Mycobacterium tuberculosis complex. Antiviral activity was not tested in that study. (Hwang et al., J Nat Prod, 2013)
- The claim that hot-water agarikon preparations are inert is backwards. The one positive influenza screen in this literature used an aqueous extract of mycelium, which named agarikon among the most promising of eleven species tested. (Teplyakova et al., Int J Med Mushrooms, 2012)
- The 2026 Saxe RCT (n=90, double-blind, placebo-controlled, 6 months) is the first human trial of agarikon. It tested an agarikon–turkey tail blend as a COVID-19 vaccine adjunct and found reduced side effects and preserved antibody levels in COVID-naive participants. It did not test treatment or prevention of viral infection. (Saxe et al., BMC Immunol, 2026)
- Agarikon establishes on conifers aged roughly 150 years or more. It is classified as Endangered, and habitat loss from old-growth logging is the primary threat to the species.
First, the Confusion: Agarikon's Names, and Why None of Them Is Agaricus
Before anything else, a clarification that matters for reading both this article and the research literature correctly.
"Agarikon" sounds like "Agaricus," and the two are routinely conflated on health websites. Agaricus is the genus containing white button mushrooms, cremini and portobello — the most widely eaten mushrooms in the world. Agarikon is a bracket fungus in a different order and a different family, with no taxonomic or pharmacological overlap. If you encounter content about agarikon that also discusses Agaricus blazei as though it were the same lineage, treat the rest of that source with caution.
The second source of confusion is that the species itself has been renamed repeatedly since it was first described in 1789. The currently accepted name is Laricifomes officinalis, in the family Laricifomitaceae. The name you will see most often in the research literature, however, is Fomitopsis officinalis: the 2019 antimicrobial review and the 2020 biological-properties review both use it,[6][4] as does the 2026 clinical trial,[1] while the 2025 comprehensive review uses Laricifomes officinalis.[2] Older texts use Fomes officinalis, Polyporus officinalis, or the original Boletus officinalis.
One name that circulates online is not real at all: "Ganoderma officinalis" is not a synonym of this species and has no standing in the nomenclatural record. Its appearance in a piece of agarikon content is a reliable signal that the content was not checked against primary sources.
Name Resolution
Which agarikon names are real, and which one is currently correct
The species has been reclassified repeatedly since 1789, so the literature carries several names for one organism. Searching any of the valid names returns research on the same mushroom.
Laricifomes officinalis
Accepted(Vill.) Kotl. & Pouzar, 1957
Currently accepted name. Family Laricifomitaceae. Used by the 2025 comprehensive review.
Fomitopsis officinalis
Synonym — widely used(Vill.) Bondartsev & Singer, 1941
Still the most common name in the research literature. Used by the 2019 and 2020 reviews and by the 2026 clinical trial.
Fomes officinalis
Historical(Vill.) Bres., 1931
Appears in early 20th-century pharmacy and mycology texts.
Polyporus officinalis
Historical(Vill.) Fr., 1821
The 19th-century name, common in European pharmacopoeias.
Boletus officinalis
HistoricalVill., 1789
The original description (basionym). All later names derive from it.
Ganoderma officinalis
Not a real name—
Not a synonym of this species. It circulates on health websites but has no standing in the nomenclatural record.
Separate point of confusion: agarikon is not Agaricus. Agaricus is the genus of white button, cremini and portobello mushrooms, in a different order and family entirely. The two names sound alike and share a Greek root, but nothing else.
Nomenclature per Species Fungorum / GBIF. Name usage in the research literature per Girometta (2019), Mycology 10(1):32–39; Muszynska et al. (2020), Chemistry & Biodiversity 17(6):e2000213; Gafforov et al. (2025), Plant Foods for Human Nutrition 80(1):77.
The definition: Agarikon (Laricifomes officinalis, syn. Fomitopsis officinalis) is an endangered polypore bracket fungus that grows on old-growth conifers, historically across Europe and northern Asia and today primarily in the Pacific Northwest of North America. It contains chlorinated coumarins, lanostane triterpenoids, polysaccharides, organic acids and phenolic compounds, with antibacterial, antiparasitic, antitumour and — in crude extracts only — antiviral activity reported in laboratory studies.[2] It was described as a medicine around 65 CE by Dioscorides, making it one of the oldest recorded medicines in Western history.
The common name comes from the ancient Greek word Dioscorides used. Some historical sources use "agaric" loosely for any bracket fungus; in current usage, "agarikon" refers specifically to this species, and that is the convention throughout this article.
Two Thousand Years of Documented Use
The Greek physician Pedanius Dioscorides described a fungal medicine called agarikon in De Materia Medica, written around 65 CE. He recommended it for tuberculosis, asthma and coughs, and noted that it grew on certain mountain trees. This is the earliest known written record of a medicinal mushroom in Western history. It is a historical record, not a clinical result, and it should be read as evidence of what people did rather than evidence that it worked.
The tradition long outlasted Dioscorides. A 2014 review of European ethnomycology examined five polypore species that were widely used in central European folk medicine — agarikon among them — for complaints including coughs, rheumatism, dysmenorrhoea and pyretic disease.[3] That review also notes how deep the practice runs: two polypore species were found among the possessions of Ötzi, the Iceman, who lived more than 5,000 years ago. It is worth being precise here, because agarikon coverage often overstates this point. The review does not describe agarikon as the single most widely used medicinal polypore on the continent; it describes it as one of five that were widely used.
By the 18th and 19th centuries agarikon had become a pharmacy staple, and that popularity contributed directly to its decline. A 2020 review documents how mass collection for pharmacy, combined with heavy demand for larch wood and resin, drove the species out of much of its natural European range.[4]
The tuberculosis use is the part of this history with the most interesting modern parallel. For centuries people used agarikon against a disease they could observe but not explain. In 2013, Hwang and colleagues isolated two previously unknown naturally occurring chlorinated coumarins from an ethanol extract of agarikon and profiled their antimicrobial activity. The profile was narrow, and the lowest MICs in the panel were against the Mycobacterium tuberculosis complex.[5] That is a genuinely striking convergence with the traditional use. It is also strictly a laboratory antibacterial result: it does not mean agarikon treats tuberculosis, and the study did not test the compounds against any virus.
For the full historical record, including the role of agarikon in Indigenous Pacific Northwest traditions and the stories that have been revised on closer examination, see The 2,000-Year Medical History of Agarikon.
One Mushroom, Twenty Centuries
Agarikon: From Ancient Cough Remedy to Modern Chemistry
The documented path of Fomitopsis officinalis — from Dioscorides’ c. 65 CE record, through European folk medicine and the collapse of its old-growth host forests, to the modern chemical and review literature.
- c. 65 CETraditional Record
Dioscorides records agarikon
The Greek physician Dioscorides documents agarikon in De Materia Medica for consumption (tuberculosis), coughs, and other respiratory and infectious complaints — one of the earliest written records of a medicinal mushroom in the Western tradition.
- Medieval–18th C.Traditional Record
European folk medicine
Agarikon persists across central European folk medicine for tuberculosis, coughs, asthma, rheumatism, and fever. A modern review of European medicinal polypores counts it among the five species most widely used in the tradition.
- 18th–19th C.Habitat & Decline
Mass-collection and decline
Fomitopsis officinalis is mass-collected for 18th- and 19th-century pharmacy while heavy demand for larch timber and resin strips its host forests. The combined pressure drives the fungus toward disappearance across much of its European range.
- 2013Modern Science
A chemical clue for the TB use
Chemists isolate two chlorinated coumarins from F. officinalis with a narrow antimicrobial spectrum and the lowest MICs against the Mycobacterium tuberculosis complex — an in vitro hint at why the ancient TB remedy was used, not clinical proof.
- 2020–2025Modern Science
Modern reviews and conservation
Review papers catalogue the fungus's coumarins, phenolics, polysaccharides, terpenoids, and sterols and their antibacterial, antiviral, anti-inflammatory, anticancer, and antioxidant activity — while flagging overexploitation and habitat loss as an urgent conservation problem.
European folk-medicine use and the five-polypore ranking per Grienke et al., Journal of Ethnopharmacology, 2014. Pharmacy history and larch-forest decline per Muszyńska et al., Chemistry & Biodiversity, 2020. Chlorinated-coumarin anti-TB activity per Hwang et al., Journal of Natural Products, 2013 (in vitro). Bioactive profile and conservation status per Gafforov et al., Plant Foods for Human Nutrition, 2025. The c. 65 CE Dioscorides entry is a documented historical record, not a clinical result.
Where Agarikon Grows, and Why It's Nearly Impossible to Find
Agarikon has demanding habitat requirements. It grows on old-growth conifers — primarily larch across its Eurasian range and Douglas fir in North America — and typically establishes only on trees aged around 150 years or older. Young plantation forests do not support it even when the tree species is right, because they lack the dead branches, exposed heartwood and bark fissures the fungus needs to colonise. This makes it one of the most habitat-restricted medicinal fungi on earth.
In Europe, agarikon is close to gone. Centuries of logging removed the old-growth habitat it depends on, and the mass pharmacy collection described above removed the fruiting bodies themselves. The 2020 review describes the species as having largely disappeared from its natural European environment.[4] The 2025 comprehensive review reaches the same conclusion globally, naming overexploitation and habitat loss as the central conservation threats and arguing that culture collections and controlled cultivation are now necessary to preserve both the species and its chemistry.[2]
In North America, the surviving populations are concentrated in old-growth forests of Washington, Oregon and British Columbia. Agarikon produces the largest and longest-lived fruiting bodies of any polypore: a single specimen can persist on its host tree for up to 75 years, adding a layer of pore tissue each season, and can exceed 40 centimetres across. But each one needs an old tree to establish on, and when that tree is logged the fungus goes with it.
Paul Stamets, the mycologist most associated with bringing agarikon into scientific conversation, began collecting tissue samples from old-growth Pacific Northwest trees to preserve the species' genetic diversity. That collection has reached 118 distinct strains, each undergoing genome sequencing, and it supplied the material for later antiviral screening work. The full story of that effort is covered in Agarikon and Paul Stamets: The Quest to Save an Endangered Mushroom.
What Makes Agarikon Biologically Active
Agarikon is not active because of a single compound. Reviews of its chemistry consistently describe several distinct classes: coumarin derivatives, triterpenoids and sterols, polysaccharides, organic acids, indole compounds and phenolics.[2][4] Understanding which class does what — and in which assay — is where most popular agarikon coverage goes wrong.
Chlorinated coumarins. These are the most distinctive chemistry in the species. Hwang and colleagues isolated two of them from an ethanol extract of agarikon in 2013: 6-chloro-4-phenyl-2H-chromen-2-one and an ethyl ester derivative, both confirmed by synthesis.[5] Naturally occurring chlorinated compounds are unusual, which makes these a real chemical signature. Their measured activity was antibacterial, with the lowest MICs against the tuberculosis complex.
Lanostane triterpenoids. These occur in the fruiting bodies. The 2019 antimicrobial review is explicit about the division of labour: chlorinated coumarins from mycelia and lanostane triterpenoids from basidiomes are responsible for antimicrobial and trypanocidal activity respectively.[6] The agarikon triterpenoids that have been isolated and tested were screened against Trypanosoma congolense, a livestock parasite — not against viruses.
Polysaccharides. These do not inhibit pathogens directly; they interact with immune receptors. Two 2024 studies purified defined heteropolysaccharides from agarikon and characterised their binding. FOBP90-1 was shown to interact with TLR-2, TLR-4, PD-L1 and VEGFR-2,[12] and FOBP50-1 with TLR-4, PD-1 and VEGF.[13] Both were tested for antitumour rather than antiviral effects, in zebrafish. For how mushroom beta-glucan signalling works more generally, see Mushroom Beta-Glucans and Immunity: The Complete Research Guide.
Organic acids. Agaricic acid is a major structural constituent and part of the reason for the mushroom's intensely bitter taste. The 2019 review documents broad-spectrum antibacterial activity for agarikon against Mycobacterium tuberculosis, Yersinia pseudotuberculosis and Staphylococcus aureus, and reports orthopoxvirus activity as well, but attributes the characterised activity to the coumarins and triterpenoids rather than to agaricic acid specifically.[6]
Here is where the most persistent error in agarikon writing enters. A specific figure — fomitopsin D inhibiting herpes simplex virus type 1 with an IC50 of 17 micrograms per millilitre — is quoted almost universally as an agarikon result. The number is real, but it belongs to Fomitopsis feei, a different, tropical bracket fungus. Those compounds have never been isolated from agarikon. Presenting the figure as agarikon's transfers a result across a species boundary without evidence that the compound is even present in this mushroom.
Compound Audit
Which isolated compounds are actually agarikon’s — and what was actually measured
Named compounds get transferred between Fomitopsis species and between assay types as claims travel. Each row pins the compound to its source organism and to the endpoint the original experiment measured.
Chlorinated coumarins
AgarikonF. officinalis (mycelium)
Antibacterial — M. tuberculosis complex
Lowest MICs of the panel
Fomitopsin D
Not agarikonFomitopsis feei (fruiting body)
Antiviral — herpes simplex virus type 1
IC₅₀ 17 μg/mL
Fomitopsins E and F
Not agarikonFomitopsis feei (fruiting body)
Antibacterial — Bacillus cereus
MIC 6.25 μg/mL
Lanostane triterpenoids
AgarikonF. officinalis
Antiparasitic — Trypanosoma congolense
IC₅₀ 7.0–27.1 μM
FOBP50-1 polysaccharide
AgarikonF. officinalis
Immune activation / antiangiogenic (zebrafish)
Binds TLR-4, PD-1, VEGF
Net result: no isolated, chemically defined compound from F. officinalis has a published anti-influenza or anti-herpes potency value. The one quantified anti-herpes figure in this literature (fomitopsin D, IC₅₀ 17 μg/mL) belongs to a different mushroom species. Agarikon’s antiviral signal exists only in crude, chemically undefined extracts.
Sources: Hwang et al. (2013), Journal of Natural Products 76(10):1916–22; Isaka et al. (2017), Tetrahedron Letters 58(18):1758–61, as reported in Girometta (2019), Mycology 10(1):32–39; Naranmandakh et al. (2018), Journal of Natural Medicines 72(2):523–29; Shen et al. (2024), International Journal of Biological Macromolecules 267(Pt 2):131320.
The Lab Evidence: What Viruses Has Agarikon Been Tested Against?
The honest summary of the antiviral literature is that agarikon's antiviral signal exists in crude extracts, not in identified compounds.
Influenza. The strongest result comes from a 2012 screen of aqueous extracts from the mycelium of eleven Altai basidiomycetes against influenza A H5N1 and H3N2 in cell culture. Agarikon was named among the most promising strains for developing antiviral preparations.[7] A later review from the same Russian virology group surveyed antiviral activity across Agaricomycetes against herpes, West Nile, influenza, HIV, hepatitis and orthopoxviruses including variola, attributing activity to polysaccharides, proteins, glycoproteins, terpenoids, melanins and nucleosides across the class.[8] A 2021 review from the same group focused on influenza specifically; notably, the mushroom it singles out for the broadest antiviral range is chaga, not agarikon.[9]
Herpes and poxviruses. The 2019 review reports orthopoxvirus activity for agarikon.[6] The most-cited specific result in this area comes from US biodefense antiviral screening, where of seven agarikon strains submitted, three showed activity described as remarkable while the remainder showed weak or no activity. That strain-to-strain variation is itself the important finding: antiviral potential in agarikon appears to be a property of particular strains rather than of the species as a whole.
A figure worth retiring. Agarikon coverage frequently repeats that an extract retained half its antiviral effect at a one-in-a-million dilution. That figure originates in patent filings rather than in a peer-reviewed experiment, and it should not be cited as a published result. It is also implausible on its face as a description of a crude extract.
The extraction claim, corrected. A rule that circulates widely holds that ethanol extracts of agarikon are the antiviral ones and hot-water preparations are inert. The published record does not support it, and in the most important respect it is backwards: the one positive influenza screen used an aqueous extract of mycelium,[7] while the ethanol study measured antibacterial activity and never ran a viral assay at all.[5] Different solvents certainly pull out different compound classes, but no extraction method has been shown to concentrate an antiviral agarikon compound, for the simple reason that no such compound has been identified.
Preparation Audit
Each agarikon preparation was tested against a different question
The common claim that ethanol extracts are antiviral and water extracts are inert does not survive contact with the papers. The one positive influenza screen used a water extract; the ethanol study measured antibacterial activity and never ran a viral assay.
Aqueous extract of mycelium
Cell cultureTeplyakova 2012
Endpoint
Influenza A (H5N1, H3N2), cell culture
Finding
Named among the most promising of 11 species screened
Only row in this table with a positive antiviral screen — and it is a water extract.
Ethanol extract
Cell cultureHwang 2013
Endpoint
Antimicrobial panel (no viral assay)
Finding
Two chlorinated coumarins; lowest MICs vs M. tuberculosis
Chloroformic fraction (Fo3)
Cell cultureAltannavch 2022
Endpoint
Liver cancer lines HepG2 / LO2
Finding
Apoptosis and NF-kB modulation; most active of six fractions
Purified polysaccharides (FOBP90-1, FOBP50-1)
Animal modelLiu 2024; Shen 2024
Endpoint
Tumour growth in zebrafish; receptor binding
Finding
Immune activation and angiogenesis inhibition
Mycelium capsule blend with turkey tail (FoTv)
Human trialSaxe 2026
Endpoint
COVID-19 vaccine adjunct, n=90 randomized
Finding
Safe; fewer side-effects and antibodies preserved in COVID-naive
What this means for a product label: no extraction method has been shown to concentrate an antiviral agarikon compound, because no isolated agarikon compound has a published antiviral potency value at all. Extraction claims on agarikon products are ahead of the evidence in every direction.
Sources: Teplyakova et al. (2012), International Journal of Medicinal Mushrooms; Hwang et al. (2013), Journal of Natural Products 76(10):1916–22; Altannavch et al. (2022), Anti-Cancer Agents in Medicinal Chemistry 22(8):1561–70; Liu et al. (2024) and Shen et al. (2024), International Journal of Biological Macromolecules; Saxe et al. (2026), BMC Immunology 27(1).
For the complete antiviral evidence review, see Agarikon and Antiviral Activity: Influenza and Herpes Research.
The 2026 Clinical Trial: What the First Human Study Actually Found
In 2026, Saxe and colleagues at UC San Diego published the first randomized, double-blind, placebo-controlled trial of agarikon in humans. Ninety participants were randomized — 52 to the active arm, 38 to placebo — and followed for six months. The product tested, abbreviated FoTv, was a mycelium blend of agarikon and Trametes versicolor (turkey tail).[1]
The design used COVID-19 vaccination as the immune challenge. Participants took eight 500 mg capsules three times daily for four days alongside vaccination, then were followed with blood draws at days 1, 3, 14, 28/42 and six months. Primary outcomes were safety, feasibility, self-reported vaccine side effects and anti-SARS-CoV-2 antibody levels. The trial was pre-registered on ClinicalTrials.gov as NCT04951336.
Participants were split by prior exposure: those with detectable antibodies at baseline were classified COVID-exposed, those without as COVID-naive. Two findings separated FoTv from placebo, and both were confined to the COVID-naive group. First, FoTv significantly reduced the number and severity of vaccine side effects on days 3 and 5. Second, antibody responses in the COVID-naive FoTv group were preserved across six months and possibly increased — an effect not observed in the other groups. In COVID-exposed participants, there was no side-effect benefit.
On safety and feasibility the trial was clean: no adverse events, overlapping confidence intervals for renal and hepatic function between arms, 100% completion and greater than 95% treatment adherence.
What this trial establishes is worth stating precisely, because it is easy to overstate. It is a safety-and-feasibility trial with immunological secondary outcomes, in a subgroup, using a two-species blend. It shows that a mycelium product can be taken safely alongside vaccination without blunting the antibody response, and that it may reduce reactogenicity in immunologically naive recipients. It does not show that agarikon prevents or treats viral infection, it does not isolate agarikon's contribution from turkey tail's, and the arms were unbalanced (52 versus 38). The authors themselves frame the work as testing a strategy, with potential application to emerging viruses, rather than as a demonstration of antiviral efficacy.
Claim Reach
What the one human trial tested vs. what the antiviral claim needs
Agarikon-containing mycelium has now been through a randomized controlled trial in people. Only one of the five dimensions below lines up with the question “does agarikon work against flu or herpes?”
How to read this: the trial is real evidence, and it is the first controlled human safety data for an agarikon-containing product (no adverse events, 100% completion). It is not evidence that agarikon treats influenza or herpes, and it was never designed to be.
Source: Saxe et al. (2026), BMC Immunology 27(1); trial registration NCT04951336.
For a full evaluation of what the lab and clinical evidence together mean for the antiviral hypothesis, see Agarikon and Paul Stamets' Antiviral Hypothesis: What the Research Actually Shows.
Beyond Antivirals: Anticancer and Immune Effects in Lab Studies
Antiviral research gets most of the attention, but agarikon's better-characterised laboratory activities are actually in oncology and immunology. Everything in this section comes from cell culture or non-mammalian animal models.
Antioxidant and anticancer fractions. A 2022 study prepared six fractions of agarikon residue — ethanolic, petroleum ether, chloroformic, ethyl acetate, butanolic and water-ethanolic — and screened them against hepatocellular carcinoma cells. All six showed antioxidant activity, but the chloroformic fraction was the standout: it promoted apoptosis in HepG2 and LO2 cells, arrested the cell cycle at G2/M, and acted through NF-kB signalling.[11] The authors are candid that only that one fraction was pursued in depth. Note that this is a fraction-level result: the paper does not attribute the activity to lanostane triterpenoids or any other named compound class.
Antitumour polysaccharides. The two 2024 studies isolated structurally defined heteropolysaccharides and tested them in zebrafish. FOBP50-1 activated immunity and inhibited angiogenesis, with surface plasmon resonance confirming binding to TLR-4, PD-1 and VEGF at micromolar-to-submicromolar affinity.[13] FOBP90-1 showed a comparable profile through TLR-2, TLR-4, PD-L1 and VEGFR-2.[12] These are careful structural studies with clear mechanistic work. They are also zebrafish studies, and the distance from a zebrafish xenograft to a human outcome is very large.
The honest framing for this whole section is that agarikon has a real and reproducible laboratory pharmacology, and that not one of these findings has been tested in a mammal, let alone a person.
Agarikon Supplements: What the Research Tells You to Look For
A small number of supplement products contain agarikon, almost all of them mycelium-based and marketed for immune support. The research supports a few narrow conclusions and undercuts several common marketing claims.
Mycelium versus fruiting body. A 2021 study grew agarikon mycelium in 10-litre bioreactors and tested whether supplementing the culture medium with zinc and magnesium salts changed its composition. It did: mycelium grown on enriched medium contained substantially more magnesium and zinc than fruiting bodies (1,261 versus 132 mg/100 g dry weight for magnesium; 183 versus 15 mg/100 g for zinc), along with more indole compounds, phenolics and L-phenylalanine.[10] This shows that cultivated mycelium can be deliberately enriched, which matters for a species too endangered to harvest at scale. It does not show that mycelium contains more of the antiviral-relevant compounds — that study measured bioelements and simple organics, not coumarins.
Extraction method. Marketing claims that a particular solvent delivers agarikon's antiviral compounds are ahead of the evidence in every direction, because no isolated agarikon compound has a published antiviral potency value. Both the water route and the ethanol route have a laboratory result attached, and neither is an antiviral result in a chemically defined preparation.
Dosing context. The only human dosing data is the 2026 trial protocol: eight 500 mg capsules three times daily for four days, as a two-species blend, in the specific context of vaccination.[1] That is a short, high-intensity, event-anchored protocol. It provides no basis for daily long-term supplementation, and no dose-ranging work has been done in humans.
Sourcing and conservation. This is the point that carries the most weight. Agarikon is Endangered, and wild harvest is straightforwardly incompatible with the species' survival — the 18th- and 19th-century pharmacy trade is part of why it vanished from Europe. Cultivated mycelium from preserved strains is both the more defensible option and the more chemically reproducible one.
A note on expectations. Nothing in the current evidence base supports using agarikon to treat or prevent an infection. The one human trial tested tolerability and immune markers around a vaccine, not illness outcomes. This article is educational and is not medical advice; anyone considering a mushroom supplement alongside prescription medication, during pregnancy, or with an immune condition or immunosuppressive therapy should discuss it with their physician first.
The Bottom Line
Agarikon (Laricifomes officinalis, syn. Fomitopsis officinalis) is the oldest documented medicinal mushroom in Western history, with a written record reaching back to about 65 CE and, since 2026, a first randomized human trial. Its laboratory pharmacology is real but narrower than its reputation: the chlorinated coumarins isolated from it are antibacterial, its lanostane triterpenoids were tested against a parasite, and its polysaccharides were tested against tumours in zebrafish. No isolated agarikon compound has a published antiviral potency value, and the widely quoted fomitopsin D herpes figure belongs to a different species. The antiviral signal exists only in crude extracts — and the one positive influenza screen used a water extract, not the ethanol extract that marketing usually credits. The 2026 RCT showed a mycelium blend was safe alongside COVID-19 vaccination and reduced side effects while preserving antibody levels in COVID-naive participants; it did not test antiviral efficacy. The species is Endangered, and conservation of old-growth forest is directly tied to both its survival and the research it makes possible.
Frequently Asked Questions
Sources & References
- 1RTHM-02244·Saxe, Gordon et al. (2026). “Polypore mushroom mycelia as an adjunct to COVID-19 vaccination: a randomized clinical trial..” BMC immunology.Study breakdown →PubMed →↩
- 2RTHM-00924·Gafforov, Yusufjon et al. (2025). “Mycochemistry, Traditional Uses, and Nutraceutical Potential of Laricifomes officinalis: A Biotechnological and Pharmacological Perspective..” Plant foods for human nutrition (Dordrecht.Study breakdown →PubMed →↩
- 3RTHM-00322·Grienke, Ulrike et al. (2014). “European medicinal polypores--a modern view on traditional uses..” Journal of ethnopharmacology.Study breakdown →PubMed →↩
- 4RTHM-00640·Muszyńska, Bożena et al. (2020). “Fomitopsis officinalis: a Species of Arboreal Mushroom with Promising Biological and Medicinal Properties..” Chemistry & biodiversity.Study breakdown →PubMed →↩
- 5RTHM-00290·Hwang, Chang Hwa et al. (2013). “Chlorinated coumarins from the polypore mushroom Fomitopsis officinalis and their activity against Mycobacterium tuberculosis..” Journal of natural products.Study breakdown →PubMed →↩
- 6RTHM-00556·Girometta, Carolina (2019). “Antimicrobial properties of Fomitopsis officinalis in the light of its bioactive metabolites: a review..” Mycology.Study breakdown →PubMed →↩
- 7RTHM-00265·Teplyakova, Tamara V et al. (2012). “Antiviral activity of polyporoid mushrooms (higher Basidiomycetes) from Altai Mountains (Russia)..” International journal of medicinal mushrooms.Study breakdown →PubMed →↩
- 8RTHM-00450·Teplyakova, Tamara V et al. (2016). “Antiviral Effect of Agaricomycetes Mushrooms (Review)..” International journal of medicinal mushrooms.Study breakdown →PubMed →↩
- 9RTHM-00723·Teplyakova, Tamara V et al. (2021). “Medicinal Mushrooms against Influenza Viruses..” International journal of medicinal mushrooms.Study breakdown →PubMed →↩
- 10RTHM-00684·Fijałkowska, Agata et al. (2021). “Fortified Mycelium of Fomitopsis officinalis (Agaricomycetes) as a Source of Biologically Active Substances Effective in the Prevention of Civilization Diseases..” International journal of medicinal mushrooms.Study breakdown →PubMed →↩
- 11RTHM-00740·Altannavch, Nyamsambuu et al. (2022). “Anti-oxidant and Anticancerous Effect of Fomitopsis officinalis (Vill. ex Fr. Bond. et Sing) Mushroom on Hepatocellular Carcinoma Cells In Vitro through NF-kB Pathway..” Anti-cancer agents in medicinal chemistry.Study breakdown →PubMed →↩
- 12RTHM-00892·Liu, Wenhui et al. (2024). “A fungal polysaccharide from Fomitopsis officinalis as a multi-target molecule to combat cancer..” International journal of biological macromolecules.Study breakdown →PubMed →↩
- 13RTHM-00907·Shen, Yongye et al. (2024). “An antitumor fungal polysaccharide from Fomitopsis officinalis by activating immunity and inhibiting angiogenesis..” International journal of biological macromolecules.Study breakdown →PubMed →↩