In 30 older Japanese adults with mild cognitive impairment, those taking lion's mane tablets had higher cognitive-scale scores than placebo at weeks 8, 12 and 16; scores dropped again 4 weeks after stopping.
AttentionNot assessedNo current independent attention assessment
EvidenceNo mapped studiesNo reviewed experiment families currently mapped
ConfidenceNot assessedFor: In 30 older Japanese adults with mild cognitive impairment, those taking lion's mane tablets had higher cognitive-scale scores than placebo at weeks 8, 12 and 16; scores dropped again 4 weeks after stopping.. No current reviewed confidence assessment for this claim.
The GapAttention not measured
Attention describes reviewed public attention, evidence shows study types, and confidence applies only to the stated claim. There is no overall score.
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We haven't called this yet. Watch it and we'll tell you when there's enough to say something useful.
Why we checked it
Interest is growing. English Wikipedia's Hericium erinaceus article had 23,996 views in September 2026, up from 19,121 in July. Research output is small: PubMed added 9 records in the 30 days to Oct 11 2026.
Here's where it actually stands
Lion's mane is an edible mushroom, Hericium erinaceus. In the US it is sold as a food and a dietary supplement, often marketed for memory, focus and mood. The FDA does not approve dietary supplements before they are sold. A few small human trials suggest possible effects on memory or thinking test scores. In one, scores fell again after people stopped taking it. A trial in young healthy adults found mostly no effect, with one faster test result. No large trial has tested it. In one trial, 4 of 49 people dropped out because of stomach upset, nausea or a rash. The trials were too small to judge safety.
What we know
In 30 older Japanese adults with mild cognitive impairment, those taking lion's mane tablets had higher cognitive-scale scores than placebo at weeks 8, 12 and 16; scores dropped again 4 weeks after stopping.
What we don't know
Does lion's mane slow memory decline in older adults with mild cognitive impairment?
Claims
In 30 older Japanese adults with mild cognitive impairment, those taking lion's mane tablets had higher cognitive-scale scores than placebo at weeks 8, 12 and 16; scores dropped again 4 weeks after stopping. · headlineAdults 50-80 with mild cognitive impairment (Japan) · Outcome: Revised Hasegawa Dementia Scale-based cognitive scoreConfidence: Not assessed · source checked
Would change this claim: If a large, registered trial with a standardized product shows a clear benefit on memory in mild cognitive impairment, we would move that from 'not settled' to 'shown in one trial'.
Source: Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. · PMID 18844328 · Phytother Res · Abstract: 30 subjects randomized into two 15-person groups; significantly increased scores at weeks 8, 12 and 16; scores decreased significantly 4 weeks after stopping · Verify ↗
In 41 healthy adults aged 18-45, one dose of lion's mane led to faster performance on one attention test at 60 minutes, but 28 days of use showed only a non-significant trend toward lower stress. The authors note null findings and a small sample.Healthy adults aged 18-45 · Outcome: Cognitive battery, stress and moodConfidence: Not assessed · source checkedSource: 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. · PMID 38004235 · Nutrients · Abstract, Results: quicker Stroop (p = 0.005) at 60 min; trend to reduced stress at 28 days (p = 0.051); null and limited negative findings also observed · Verify ↗
In a 49-week pilot trial in Taiwan, 49 people with mild Alzheimer's disease were randomized to a mycelium product enriched in erinacine A or to placebo, and 41 finished. The authors report better results than placebo on some cognitive and daily-living measures, but most results in the abstract are changes within each group rather than comparisons with placebo. Four people dropped out because of stomach upset, nausea or rash.Adults with mild Alzheimer's disease (Taiwan) · Outcome: CASI, MMSE, IADL and biomarkersConfidence: Not assessed · source checkedSource: Erinacine A-enriched Hericium Erinaceus Mycelia for Improvement of Recognition, Vision, and Functional MRI Alterations · NCT NCT04065061 · Chung Shan Medical University · Full text (PMC7283924), Results: 49 randomized, 41 analyzed; Abstract: within-group CASI decline (placebo) and MMSE gain (treatment), between-group IADL difference; 4 dropouts for AEs (registered enrollment 68) · Verify ↗Source: Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study. · PMID 32581767 · Front Aging Neurosci · Full text (PMC7283924), Results: 49 randomized, 41 analyzed; Abstract: within-group CASI decline (placebo) and MMSE gain (treatment), between-group IADL difference; 4 dropouts for AEs (registered enrollment 68) · Verify ↗
Mapped studies / experiment families
One experiment counts once, even with several registrations or publications. Counts above describe the headline claim.
No reviewed experiment families mapped yet.
Studies & active trials
Only papers and registered trials an editor reviewed for this page. Being listed is not a finding; the claims above say what they show.
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.PMID 38004235 · DOI 10.3390/nu15224842Study · Published · Nov 20, 2023 · NutrientsOpen source ↗
Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial.PMID 18844328 · DOI 10.1002/ptr.2634Study · Published · Phytother ResOpen source ↗
Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study.PMID 32581767 · DOI 10.3389/fnagi.2020.00155Study · Published · Front Aging NeurosciOpen source ↗
Lion's Mane Dosing on Attention and MoodNCT NCT07759687Trial · Not yet recruiting · Aug 12, 2026 · Northumbria UniversityOpen registry record ↗
Study Evaluating the Quality and Effects of Lion's Mane Product on Cognitive HealthNCT NCT06870136Trial · Recruiting · Mar 11, 2025 · M2 IngredientsOpen registry record ↗
Erinacine A-enriched Hericium Erinaceus Mycelia for Improvement of Recognition, Vision, and Functional MRI AlterationsNCT NCT04065061Trial · Completed · Chung Shan Medical UniversityOpen registry record ↗
What would change our mind
If a large, registered trial with a standardized product shows a clear benefit on memory in mild cognitive impairment, we would move that from 'not settled' to 'shown in one trial'.
If case reports or a trial identify a consistent safety signal (for example liver injury or allergy), we would add it to the opening.
Erinacine A-enriched Hericium Erinaceus Mycelia for Improvement of Recognition, Vision, and Functional MRI AlterationsChung Shan Medical University · checked Oct 11, 2026 · NCT NCT04065061; status:COMPLETED
Lion's Mane Dosing on Attention and MoodNorthumbria University · checked Oct 11, 2026 · NCT NCT07759687; status:NOT_YET_RECRUITING; primary completion 2026-11 (estimated)
Study Evaluating the Quality and Effects of Lion's Mane Product on Cognitive HealthM2 Ingredients · checked Oct 11, 2026 · NCT NCT06870136; status:RECRUITING; primary completion 2025-07-25 (estimated)
Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial.Phytother Res · checked Oct 11, 2026 · PMID 18844328; DOI 10.1002/ptr.2634
Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study.Front Aging Neurosci · checked Oct 11, 2026 · PMID 32581767; DOI 10.3389/fnagi.2020.00155
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 · checked Oct 11, 2026 · PMID 38004235; DOI 10.3390/nu15224842
Does lion's mane slow memory decline in older adults with mild cognitive impairment?
Evidence comes from small trials of different products, one of which showed the effect fading after stopping.
What would answer it: A registered, adequately sized randomized trial lasting at least 6-12 months with a standardized product. Current registered studies are small or industry-run (NCT06870136, 150 participants, status not updated since 2025-03; NCT07759687, 24 participants).
Nothing is settled in people. The few randomized trials are small (30 to 49 people) and short, and most used different products.