Lion's Mane Side Effects: What the Research Shows (2026)
Lion's Mane is one of the safer adaptogenic supplements: 2025 OECD-guideline toxicology established a NOAEL of 2,000 mg/kg/day. Clinical trials report only mild, rare effects; the main caution is mushroom allergy.
Lion’s mane supplement side effects are rare and generally mild: clinical trials at doses up to 3 g/day for 16 weeks reported only transient digestive discomfort. A 2025 systematic review by Dr. Aditya Menon published in Frontiers in Nutrition confirmed lion’s mane’s strong safety profile across available human studies, with no serious adverse events attributable to the supplement (Menon et al., 2025). The Memorial Sloan Kettering Cancer Center database notes lion’s mane may have antiplatelet activity, warranting caution before surgery, but for most users, is lion’s mane safe? The evidence says yes at standard doses.
Reviewed by Tao Wu, Founder of YourHealthier · Editorial Policy
The extract (Hericium erinaceus) is one of the safer adaptogenic supplements on the market, with a strong toxicology profile and few reported adverse events in human trials. Realistic side effect picture: mild GI symptoms in some users, skin reactions or itching in a small minority, rare but documented allergic reactions including one case of anaphylaxis, and a handful of contraindications you should know about before starting.
A bigger problem with lion's mane content online isn't downplayed risk, it's manufactured fear. You'll find articles claiming lion's mane causes brain damage, hormonal disruption, liver injury, and cancer. Most of these claims trace to a single Reddit community, anecdotal reports, or in vitro studies misinterpreted as human evidence. This guide separates the documented from the speculative, with citations to peer-reviewed toxicology and clinical studies.
What does the safety evidence show at a glance?
| Study | Population / Dose | Duration | Adverse Events |
|---|---|---|---|
| Mori 2009 | 30 adults age 50-80, mild cognitive impairment, 3 g/day | 16 weeks | No significant adverse events |
| Docherty 2023 | 41 healthy adults age 18-45, 1.8 g/day | 28 days | No significant adverse events |
| Chen 2022 (toxicology) | Rats, beta-glucan extract up to 2,000 mg/kg/day | 90 days subchronic | NOAEL = highest dose tested; no genotoxicity |
| Mahadevan 2025 (toxicology) | Rats, whole mushroom powder up to 2,000 mg/kg/day | Acute + 90 days | No treatment-related effects at any dose |
| Kobernick 2022 (case report) | 43-year-old male, food consumption | Single exposure | First documented anaphylaxis case |
| NIH LiverTox | Database review | Ongoing | No documented hepatotoxicity attributable to lion's mane alone |
Lion's Mane Supplement Side Effects: What Are Lion's Mane Side Effects?
Most-reported side effects, ranked by frequency in clinical and case-report literature:
- Mild GI symptoms — bloating, gas, soft stools (most common, usually transient)
- Itchy skin or rashes, uncommon, possibly allergy-related
- Allergic reactions, rare; ranges from mild urticaria to one documented case of anaphylaxis
- Mild headache or dizziness — uncommon, usually dose-related
- Theoretical interactions, blood thinners, diabetes medications (mechanism-based, not strongly documented)
Across published clinical trials. Mori 2009 (3 g/day for 16 weeks in older adults with mild cognitive impairment), Docherty 2023 (1.8 g/day for 28 days in young adults) — no clinically meaningful adverse events were reported (PubMed, PMC). A 2025 OECD-guideline toxicology assessment by Mahadevan et al. tested whole lion's mane powder up to 2,000 mg/kg/day and found no treatment-related adverse effects, no genotoxicity, and no subchronic oral toxicity (PubMed).
What are the common GI side effects?
Lion's mane's most common side effect is mild digestive upset: bloating, gas, slightly loose stools, or occasional nausea. These are usually transient and dose-related. Starting at half dose, taking it with food, and building up gradually resolves most cases. Serious reactions are rare in healthy adults.
The most common complaint among lion's mane users is mild digestive upset, bloating, gas, slightly loose stools, or occasional nausea. These symptoms reflect normal adjustment to a high-fiber, beta-glucan-rich supplement and usually resolve within 1-2 weeks.
Why it happens: lion's mane fruiting body is rich in indigestible polysaccharides (mostly beta-glucans) that act as prebiotic substrate for gut bacteria. As your microbiome adjusts to the new fiber load, you may experience fermentation byproducts — gas, bloating, or shifts in bowel patterns. A 2021 pilot study by Xie et al. on short-term lion's mane consumption documented modest changes in gut microbiota composition without any clinically significant symptoms in most participants.
Practical adjustment: start at half the label dose for the first week, take with food, and slowly titrate up. If symptoms persist beyond 2 weeks, switch from whole-mushroom powder to a hot-water extract (which removes much of the indigestible fiber while keeping the bioactive compounds).
Can lion's mane cause itchy skin or allergies?
Lion's Mane was well-tolerated at 3 g/day in clinical trials, with adverse-event rates comparable to placebo. The literature contains isolated case reports of skin rash and one respiratory reaction in individuals with mushroom allergies. Anyone with known mushroom or mold allergies should avoid it; others may experience mild GI adjustment during the first week.
Reported skin reactions in published clinical and case-report literature include:
- Pruritus (itching), without visible rash, sometimes within hours of ingestion
- Urticaria (hives), raised, itchy welts on the skin
- Contact dermatitis — in people handling fresh mushrooms
- Generalized rash, uncommon, sometimes linked to higher-dose extracts
If you notice itching, hives, or skin irritation within hours of starting lion's mane, stop immediately. Mild reactions typically resolve within 24 hours with antihistamines like cetirizine or diphenhydramine. Persistent or worsening symptoms warrant medical evaluation.
Has lion's mane ever caused anaphylaxis?
In 2022, Kobernick et al. published the first known case of anaphylaxis to lion's mane in Annals of Allergy, Asthma & Immunology. A 43-year-old male developed abdominal pain, diarrhea, hives, and angioedema within minutes of consuming the mushroom. Symptoms resolved over 24 hours after Benadryl. Skin prick testing with fresh H. erinaceus was positive (3/3 mm wheal), confirming a true IgE-mediated allergy. The patient was prescribed an epinephrine auto-injector and advised to strictly avoid lion's mane.
One case in millions of users doesn't mean lion's mane is dangerous, but it does mean true mushroom allergies exist. People with known fungal allergies, asthma, or food allergies in general should be more cautious. Start at a very low dose, monitor for symptoms, and have antihistamines on hand for the first week.
Is lion's mane safe for the liver?
You'll see articles claiming lion's mane causes liver damage. Look at the actual evidence: The NIH LiverTox database; the authoritative US reference on drug-induced liver injury, lists lion's mane under "herbal and dietary supplements" with no published cases of hepatotoxicity attributable to lion's mane alone ( NCBI Bookshelf ).
The NIH LiverTox database; the authoritative US reference on drug-induced liver injury, lists lion's mane under "herbal and dietary supplements" with no published cases of hepatotoxicity attributable to lion's mane alone (NCBI Bookshelf). Mahadevan's 2025 toxicology study evaluated liver function parameters in subchronic rat studies and found no histopathological evidence of hepatotoxicity at doses up to 2,000 mg/kg/day. Liver weights increased slightly at the highest dose, but enzyme markers (AST, ALT, bilirubin) remained within normal range and pathology was clean.
Caveat: some commercial mushroom supplements contain contaminants, heavy metals, mycotoxins from improper drying, or adulterants. Liver damage risk in those cases comes from the contaminant, not lion's mane itself. This is why third-party testing matters more for mushroom supplements than for many other categories.
Is lion's mane safe during cancer treatment?
Actual in vitro research shows the opposite of what the fear-based posts claim. A study published in the International Journal of Medicinal Mushrooms tested lion's mane water extract on MCF-7 estrogen receptor-positive (ER+) breast cancer cells and found it inhibited cell viability in a dose-dependent manner, induced apoptosis, and showed complementary effects with tamoxifen, meaning it made the cancer drug more effective, not less. Medical News Today's review of available data concluded "there is no strong scientific evidence to suggest that lion's mane mushroom significantly affects estrogen levels."
Still, if you're undergoing active cancer treatment, do not add any supplement, including lion's mane, without your oncologist's input. Reason: not that lion's mane is dangerous; it's that supplement-drug interactions during cancer treatment are an area where every variable matters and clinical evidence is too thin to predict individual outcomes.
Dr. Karen Sullivan (board-certified neuropsychologist) reviews the clinical evidence on lion's mane for brain health, including safety considerations and what the research actually supports.
Do side effects differ in men vs women?
Adverse events in Lion's Mane trials matched placebo at 3 g/day; the compound is remarkably well-tolerated. The exceptions live in allergy: documented case reports of skin rash and one bronchial reaction, all in mushroom-sensitive individuals. First-week GI adjustment occurs occasionally. Mold and mushroom allergy is the one absolute exclusion.
Women considering pregnancy or breastfeeding: safety data in pregnancy is essentially absent. Default position: avoid during pregnancy and lactation. Lion's mane hasn't been associated with reproductive toxicity in animal studies at standard doses, but human data doesn't exist for these populations.
Men with bleeding disorders or on blood thinners: lion's mane has shown mild anticoagulant activity in some animal and in vitro studies. If you're on warfarin, apixaban, rivaroxaban, or daily aspirin, discuss with your prescriber before starting. Risk is theoretical rather than documented, but the rationale for caution is real.
What are the long-term side effects?
No long-term harm has been documented for lion's mane in the available human trials, which are short and small. Most studies run weeks to a few months with only mild GI effects reported. Long-term safety data is limited, so treat sustained use as low-risk but not formally proven.
Long-term human data on lion's mane is limited but reassuring. The longest published clinical trial — Mori 2009, ran for 16 weeks at 3 g/day with no significant adverse events. Toxicology data extends much further: 90-day subchronic rat studies at 2,000 mg/kg/day showed no organ damage, no genotoxicity, and no significant hematological changes (Chen 2022, PubMed).
Translation: animal data supports months of daily use at very high doses without harm. Human data supports the same at typical supplement doses, though we don't have year-plus RCT data the way we do for some medications. The reasonable practical approach: cycle if you want to be cautious (8-12 weeks on, 2-4 weeks off), or take continuously if you're tolerating it well after the first month.
Who should not take lion's mane?
The honest list: People with known mushroom allergies , even if you're not specifically allergic to lion's mane, cross-reactivity is possible Pregnant or breastfeeding women — no safety data in these populations On blood thinners or with bleeding disorders , theoretical additive anticoagulant effect On diabetes medications (insulin, sulfonylureas) , lion's mane may affect blood sugar levels; additive hypoglycemia possible Scheduled for surgery within 2
- People with known mushroom allergies, even if you're not specifically allergic to lion's mane, cross-reactivity is possible
- Pregnant or breastfeeding women — no safety data in these populations
- On blood thinners or with bleeding disorders, theoretical additive anticoagulant effect
- On diabetes medications (insulin, sulfonylureas), lion's mane may affect blood sugar levels; additive hypoglycemia possible
- Scheduled for surgery within 2 weeks — discontinue due to bleeding risk
- Active asthma with mushroom or fungal sensitivities, could trigger respiratory symptoms
- Currently undergoing cancer treatment, coordinate with oncologist due to potential interactions with chemotherapy or hormone therapy
Does lion's mane interact with medications?
| Medication / Supplement | Interaction | Risk | Action |
|---|---|---|---|
| Warfarin / DOACs (apixaban, rivaroxaban) | Theoretical additive anticoagulant effect | Moderate | Discuss with prescriber; monitor INR if on warfarin |
| Daily aspirin / NSAIDs | Additive antiplatelet effect | Moderate | Use with caution; discontinue 2 weeks before surgery |
| Insulin / sulfonylureas | Possible additive blood-sugar lowering | Moderate | Monitor blood glucose; consult prescriber |
| Immunosuppressants | This compound has immunomodulatory effects — could interfere | High | Avoid; discuss with specialist |
| Chemotherapy / cancer treatment | Unpredictable interactions during active treatment | High | Avoid unless oncologist approves |
| Ashwagandha | Complementary, different mechanisms (cortisol vs NGF) | Safe | Common nootropic stack |
| Magnesium glycinate | Complementary, sleep and nervous system support | Safe | Often stacked for sleep + cognition |
How to Minimize Lion's Mane Side Effects
To minimize side effects, start at half the usual dose and take lion's mane with food, then increase gradually over one to two weeks. Choose a fruiting-body extract over cheap mycelium-on-grain, and stop if you notice any skin or breathing reaction, which can signal a rare allergy.
| Issue | Adjustment |
|---|---|
| GI upset (bloating, gas) | Start at half dose; take with food; switch to extract (less fiber) |
| Mild itching / skin reaction | Stop immediately; antihistamine if needed; do not restart |
| Headache or dizziness | Reduce dose by 50%; ensure hydration |
| Sleep disruption | Take in morning rather than evening |
| Suspected allergy (any reaction) | Discontinue; consult allergist for skin testing if reaction was significant |
| No effect after 4 weeks | Check extract type (fruiting body preferred over mycelium-on-grain) |
What's our approach to lion's mane?
Our Lion's Mane uses fruiting body extract, not mycelium-on-grain, standardized for beta-glucan content. The mushroom powder used has passed OECD-guideline toxicology testing of the type referenced in Mahadevan 2025. Every batch is third-party tested for heavy metals, mycotoxins, and microbial contaminants; results are on our Lab Results page. For comparison with other adaptogens, see Lion's Mane vs Ashwagandha.
Related Research
- DOI: 10.1007/978-3-319-51639-4_2
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What's new in lion's mane research (2025–2026)?
Lion’s mane research kept expanding in 2025–2026. A registered clinical trial (NCT06870136) is now evaluating extract quality and human outcomes, adding to a still-small but growing interventional evidence base. What does lion's mane's safety profile show? Lion's mane has one of the cleanest safety profiles in the functional mushroom space, but that statement needs context.
What does lion's mane's safety profile show?
Lion's mane has one of the cleanest safety profiles in the functional mushroom space, but that statement needs context. The Mori 2009 RCT, which remains the most-cited human trial, administered 3,000 mg of whole fruiting body powder daily for 16 weeks with no serious adverse events. The Nagano 2010 trial used 2,000 mg daily for 4 weeks in women with mild complaints and reported no safety concerns. Neither study detected liver enzyme changes, kidney function alterations, or hematological abnormalities.
The side effects that do appear in user reports and smaller studies are mild and predictable. GI discomfort (bloating, loose stool) affects an estimated 5 to 8% of users, typically in the first week and especially at higher doses or on an empty stomach. Taking lion's mane with food resolves this for most people. Allergic reactions are possible in individuals with mushroom allergies, and cross-reactivity with other fungal allergens has been documented in case reports. If you have ever reacted to any edible mushroom, treat lion's mane as potentially contraindicated and discuss with your allergist.
A more complex concern involves immune modulation. Lion's mane contains beta-glucans that stimulate innate immune activity, which is generally considered beneficial but could theoretically be problematic for people on immunosuppressive medications or with autoimmune conditions. No human trial has demonstrated this risk, but the mechanism is plausible enough that most practitioners recommend caution in these populations.
For the full evidence on what lion's mane offers, see our lion's mane benefits guide. If you are evaluating products, our fruiting body vs mycelium comparison explains why source material matters for both efficacy and safety. For dosing guidance, lion's mane dosage covers the clinical trial protocols. And if you are considering lion's mane for a specific cognitive concern, our lion's mane for brain fog article addresses realistic expectations.
Who should avoid lion's mane?
While lion's mane has an excellent safety profile in clinical settings, several populations warrant extra caution. People with mushroom allergies should treat lion's mane as potentially cross-reactive until proven otherwise. No formal cross-reactivity study has been published, but immunological principles suggest that individuals who react to common culinary mushrooms (shiitake, oyster, enoki) may share IgE sensitivity to Hericium erinaceus. Start with a quarter dose and wait 48 hours before escalating.
People on anticoagulant or antiplatelet medications (warfarin, aspirin, clopidogrel) should exercise caution. Preclinical data suggests lion's mane may have mild antiplatelet activity through hericenone B-mediated inhibition of platelet aggregation. While this has not been demonstrated to cause bleeding problems in human studies, the theoretical additive effect with pharmaceutical anticoagulants justifies caution and physician awareness.
People scheduled for surgery should discontinue lion's mane at least 2 weeks prior, consistent with general supplement discontinuation guidelines. This is a precautionary measure related to the antiplatelet concern above and to avoid any unknown interactions with anesthetic agents. There is no specific evidence of surgical complications from lion's mane, but the absence of evidence is not evidence of absence in a compound with limited long-term human data.
Pregnant and breastfeeding women lack sufficient safety data to make a recommendation in either direction. No human trial has enrolled pregnant women, and the developmental toxicity data is limited to animal studies that showed no adverse effects. Most practitioners recommend avoidance during pregnancy as a default precaution for any supplement without specific pregnancy safety data.
Duration of use: is long-term lion's mane supplementation safe?
The honest answer is that we do not know, because the longest published human trial (Mori 2009) ran for only 16 weeks. Beyond that, we are extrapolating from the absence of safety signals rather than from demonstrated long-term safety. This is a common problem in supplement research: funding for 12 to 16 week trials is available; funding for 1 to 5 year safety surveillance is not.
What we can say: the Mori 2009 participants showed no adverse trends in any safety marker (liver enzymes, kidney function, hematology) that would suggest a delayed toxicity signal building during the trial period. The cognitive improvements reversed 4 weeks after discontinuation, which confirms that lion's mane requires ongoing supplementation to maintain its effects but also suggests that the biological changes are functional rather than structural, meaning they are likely reversible and do not represent permanent alterations to neural tissue.
Traditional use data provides additional context: lion's mane has been consumed as a culinary mushroom in East Asian cuisines for centuries, and as a medicinal mushroom in Traditional Chinese Medicine for at least several hundred years. No traditional toxicity warnings exist for long-term consumption, though traditional preparations (whole mushroom in soups) deliver different compound profiles than modern concentrated extracts.
The pragmatic approach: supplement daily for 12 to 16 weeks (matching the trial duration with demonstrated safety), then reassess. If cognitive benefits are present, continue with periodic breaks (4 weeks on, 1 week off) to prevent any theoretical receptor desensitization, though no evidence for lion's mane tolerance development exists. Annual blood work (comprehensive metabolic panel, liver enzymes) provides a reasonable safety monitoring baseline.
What does lion's mane do that makes side effects worth monitoring?
Lion's mane stimulates the production of nerve growth factor (NGF), a protein essential for neuron maintenance, myelination, and synaptic plasticity. This is not a mild, passive mechanism — NGF is a potent signaling molecule that influences neural architecture. The reason side effects are worth monitoring, even though they are rare and mild, is that any compound capable of genuinely altering neurotrophin levels has the potential for effects beyond the intended target. The Mori 2009 RCT showed that cognitive improvements reversed 4 weeks after stopping supplementation, confirming that lion's mane produces functional rather than structural changes. For the full cognitive evidence, see lion's mane benefits.
For people taking lion's mane alongside other supplements or medications: the compound has no documented drug interactions in the published literature. Its mechanism (NGF stimulation via hericenones and erinacines) does not involve the cytochrome P450 enzyme system that mediates most drug-supplement interactions. However, the antiplatelet effect noted in preclinical studies means that people on anticoagulants should inform their physician. The absence of documented interactions does not mean they are impossible, it means the interaction data set is still thin compared to well-studied supplements like berberine or magnesium.
For completeness: lion's mane has no documented interaction with common supplements including magnesium, ashwagandha, creatine, omega-3, or vitamin D. It can be safely incorporated into a multi-supplement regimen without timing restrictions or absorption concerns. The only supplements that share a mechanism with lion's mane are other NGF-stimulating compounds (like bacopa monnieri), and even these do not produce documented negative interactions, they offer redundant NGF support through different molecular pathways.
The most commonly searched lion's mane side effect question — "does lion's mane cause anxiety?", has a straightforward answer: no. The Nagano 2010 trial found reduced anxiety scores, not increased. No human trial has documented anxiety as a side effect. Isolated online reports of anxiety after starting lion's mane are more likely coincidental (anxiety fluctuates naturally) or related to another variable that changed simultaneously (new medication, life event, caffeine change). If you experience anxiety that correlates with starting lion's mane, discontinue for 2 weeks and observe whether it resolves. If it does, the association may be real for your individual neurochemistry despite the absence of population-level evidence.
Does product quality affect safety?
Most discussions of lion's mane side effects focus on the compound itself, but for a substantial proportion of users who experience adverse reactions, the issue is product quality rather than lion's mane pharmacology. Mycelium-on-grain products that contain 40 to 60% residual grain starch deliver a different compound profile than the fruiting body extracts used in clinical trials. Contaminants, heavy metals, or allergenic grain proteins in low-quality products can cause GI symptoms, headaches, or allergic reactions that get attributed to "lion's mane side effects" when they are actually product quality issues.
The quality verification steps described in our fruiting body vs mycelium guide are not just efficacy considerations, they are safety considerations. A product with verified beta-glucan content (≥25%), confirmed fruiting body source, and third-party heavy metal testing eliminates most of the quality-related adverse reaction risk. When reading online reports of lion's mane side effects, consider whether the reporter was using a quality-verified product before applying their experience to your own decision.
Why YourHealthier Lion's Mane
The cognitive and nerve-support benefits in this article depend on getting real mushroom bioactives — hericenones and erinacines, not grain filler labeled as mushroom powder. Our Lion's Mane delivers 1,000 mg of organic Hericium erinaceus per serving, standardized to 40% polysaccharides, with grain-free processing that preserves the compounds this mushroom is actually studied for. Every batch is third-party tested and COAs are published on our Lab Results page. If you are taking Lion's Mane for focus and brain support, the only version worth your money is one that proves what is actually in it.
Frequently Asked Questions
What are the most common side effects of lion's mane?
Mild GI upset is the most common — bloating, gas, soft stools, usually transient and dose-related. Skin reactions (itching, mild rash) occur in a smaller subset, possibly related to allergy. Clinical trials including Mori 2009 (3 g/day for 16 weeks) and Docherty 2023 (1.8 g/day for 28 days) reported no significant adverse events in study populations.
Can lion's mane cause an allergic reaction?
Yes, though it's uncommon. Reactions range from mild skin itching to one documented case of anaphylaxis (Kobernick et al. 2022, Annals of Allergy, Asthma & Immunology). People with known mushroom or fungal allergies are at higher risk. Stop immediately and seek medical care if you experience hives, difficulty breathing, or swelling within hours of taking lion's mane.
Does lion's mane affect the liver?
No published cases of liver damage have been attributed to lion's mane alone. The NIH LiverTox database lists it with no concern flags. 2025 toxicology data showed no liver damage at doses up to 2,000 mg/kg/day in rats. Liver injury risk in some online reports likely traces to contaminants (heavy metals, mycotoxins) in poorly tested commercial products, not lion's mane itself.
Can I take lion's mane during oncology treatment or alongside tamoxifen?
Discuss with your oncologist. The fear that lion's mane "increases estrogen" is not supported by clinical evidence, in vitro studies show it actually inhibits ER+ breast cancer cells and synergizes with tamoxifen rather than working against it. However, supplement-drug interactions during active cancer treatment are an area where individual judgment from your medical team matters more than general advice.
Does lion's mane cause itchy skin?
It can in some users. Pruritus (itching) without visible rash is one of the more frequently reported mild reactions, possibly reflecting a low-grade allergic response. If itching appears within hours of starting lion's mane and persists, stop the supplement. Mild cases resolve within 24 hours of discontinuation.
Who should not take lion's mane?
Avoid if you have known mushroom or fungal allergies, are pregnant or breastfeeding, on blood thinners (warfarin, DOACs, daily aspirin), on diabetes medications without monitoring, on immunosuppressants, scheduled for surgery within 2 weeks, or currently undergoing cancer treatment. Always discuss with your healthcare provider if you have a chronic condition or take prescription medications.
Are there long-term side effects of lion's mane?
Long-term human RCT data is limited (most trials run 8-16 weeks), but the picture is reassuring. Animal toxicology shows no cumulative organ damage at doses far above standard supplement levels. Mori 2009 ran for 16 weeks with no adverse events. Cycling (8-12 weeks on, 2-4 weeks off) is a reasonable cautious approach, though daily long-term use appears safe in healthy adults based on available evidence.
Should I take lion's mane mycelium or fruiting body extract?
Fruiting body extract is the better-studied form and contains higher concentrations of the bioactive compounds (hericenones, beta-glucans) most associated with cognitive and nerve health benefits. Mycelium-on-grain products often contain significant starch from the growing substrate and may have lower bioactive content per gram. For side effect profile, both are generally well-tolerated.
References
- Mahadevan, S., et al. (2025). "A toxicological assessment of Hericium erinaceus (Lion's mane) and Trametes versicolor (Turkey tail) mushroom powders." Frontiers in Toxicology, 7. PubMed · PMC
- Chen, X., et al. (2022). "90-day subchronic toxicity and genotoxicity studies of Hericium erinaceus beta-glucan extract." Regulatory Toxicology and Pharmacology. PubMed
- Mori, K., Inatomi, S., Ouchi, K., Azumi, Y., & Tuchida, T. (2009). "Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial." Phytotherapy Research, 23(3), 367–372. PubMed
- Docherty, S., et al. (2023). "The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study." Nutrients, 15(22), 4842. PMC
- Kobernick, A. (2022). "Dangers at the Dinner Table — A Report of Anaphylaxis to Lion's Mane Mushroom." Annals of Allergy, Asthma & Immunology, 129(5), S107. DOI
- NIH National Library of Medicine. (2024). "Lion's Mane." LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. NCBI Bookshelf
- 2025 Systematic Review. "Benefits, side effects, and uses of Hericium erinaceus as a supplement: a systematic review." PMC
- Xie, X.Q., et al. (2021). "Influence of short-term consumption of Hericium erinaceus on serum biochemical markers and the changes of the gut microbiota." Nutrients, 13(3), 1008.
This article is for informational purposes only and is not intended as medical advice. Always consult your healthcare provider before starting any new supplement, especially if you have mushroom allergies, are on prescription medications, or have a chronic medical condition.
Disclosure: YourHealthier sells lion's mane. We've covered the side effects without spin, including the anaphylaxis case, the skin reaction frequency, and the cancer-treatment caution that most product pages skip. If lion's mane isn't right for your situation, our product isn't right for you, and we'd rather you know upfront. See our Editorial Policy.
This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not intended as medical advice.
| Metric | Value |
|---|---|
| NOAEL (mg/kg/day) | 2,000 |
| Clinical side effects | mild, rare |
| Primary caution | mushroom allergy |
| Guideline standard | OECD 2025 tox |
| Trial AE rate | near placebo |
| Source: 2025 OECD toxicology; Mori 2009; Docherty 2023 | |
Sources verified: All PubMed citations and external references in this article were last verified onJune 13, 2026.
Disclosure: YourHealthier manufactures and sells the supplements discussed in this article. All health claims are based on published peer-reviewed research cited above. We earn revenue from product sales linked in this article.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.
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