L-Ergothioneine.com Editorial Team
Published by an independent editorial team. Individual medical or scientific credentials are not claimed; named reviewers appear only after their role is documented.
About the publication →The independent guide to L-ergothioneine
L-Ergothioneine:
The evidence, clearly.
Learn what ergothioneine is, why researchers are studying it in healthy aging, where it occurs naturally, what human studies show, and how to evaluate supplements.
IndependentSource-ledUpdated Aug. 2026
In 60 seconds
A nutrient with an unusual route through the body
Ergothioneine is a naturally occurring sulfur-containing amino-acid derivative found particularly in mushrooms and certain foods. Humans obtain it through diet and possess a specialized transporter that concentrates it in selected cells and tissues.
Primary sources: transporter discovery ↗ · human uptake study ↗ · dietary-source analysis ↗
Human research is developing. This guide shows where the science is promising—and where confident claims move beyond the evidence.
Read the complete explanation →Who, how and why
Trust starts with visible limits
Health information should make its authorship, method, commercial relationships and medical scope easy to inspect.
Primary-source checking
Claims are classified by study design and checked against primary or authoritative sources. AI may assist organization and formatting, but does not independently approve health claims.
Read the editorial policy →Commercial relationships disclosed
No affiliate product links are active at launch. Future commissions, samples, sponsorships or direct financial relationships will be labeled and kept separate from evidence assessments.
Read the disclosure →Education, not personal care
This site does not diagnose, treat or provide individualized medical advice. Discuss supplement decisions with a qualified healthcare professional who knows your circumstances.
Read the medical disclaimer →Registry snapshot
What is being reviewed—and what is not finished
Process statuses are not evidence ratings. Final classifications appear only after the research brief and human approval are complete.
Cognitive health
Two randomized trials and prospective cohorts are undergoing adversarial review.
View registry statusSleep
Early controlled signals are being checked for outcome selection and replication.
View registry statusHealthy aging
Human associations and preclinical lifespan findings are being separated.
View registry statusCellular protection
Mechanistic plausibility has not yet passed the full review process.
View registry statusCardiovascular health
No rating will be assigned before a complete evidence brief.
View registry statusSkin health
Product-specific evidence requires attribution and independence checks.
View registry statusWhy ergothioneine is unusual
From the plate to the research question
Established transport biology on the left; open clinical questions on the right.
- 01
Humans do not synthesize meaningful amounts
Ergothioneine enters the human system mainly through diet.
- 02
Food supplies the compound
Mushrooms are leading sources; content varies by species and method.
- 03
A specialized transporter moves it
SLC22A4—also called ETT or OCTN1—supports cellular uptake.
- 04
Selected cells can concentrate it
Distribution is shaped by transporter expression, not simple diffusion.
- 05
Researchers test what that means
Mechanistic plausibility must be followed by controlled human outcomes.
Food sources
Mushrooms lead the list.
The numbers need context.
Oyster, lion’s mane, shiitake, porcini and other mushrooms appear in primary food analyses, but values vary by species, growing conditions, sample preparation and measurement method.
See foods highest in ergothioneine →01Oyster mushroomsHigh in multiple datasets
02Lion’s maneHigh in a 2023 analysis
03Shiitake & porciniSpecies and source vary
04Beans, grains & organ meatsDetected in selected analyses
Quantitative values publish only after unit and citation verification.
Latest human research
The study—before the headline
The Effect of Ergothioneine Supplementation on Cognitive Function, Memory, and Sleep in Older Adults with Subjective Memory Complaints: A Randomized Placebo-Controlled Trial
- Intervention
- 10 mg/day, 25 mg/day, or placebo
- Duration
- 16 weeks
Finding: Supplementation increased plasma ergothioneine, but the primary composite-memory outcome did not show a significant treatment effect at 16 weeks. Selected secondary, subjective, or time-by-treatment signals were reported.
Important limitation: The primary cognitive outcome was null; an early within-group signal was not sustained; several positive findings were secondary, subjective, per-protocol, or within-group results.
Investigating the efficacy of ergothioneine to delay cognitive decline in mild cognitively impaired subjects: A pilot study
- Intervention
- 25 mg, three times weekly
- Duration
- 1 year
Finding: The ergothioneine group improved on a learning assessment and showed a different neurofilament-light trajectory than placebo; routine blood, kidney and liver safety markers did not change.
Important limitation: Very small pilot sample; exploratory outcomes; not adequate to establish prevention or treatment of cognitive decline.
Serum ergothioneine and risk of dementia in a general older Japanese population: the Hisayama Study
- Intervention
- No intervention; baseline serum ergothioneine
- Duration
- Median 11.2 years
Finding: Higher serum ergothioneine was associated with lower incidence of all-cause dementia, Alzheimer’s disease, and non-Alzheimer dementia after multivariable adjustment.
Important limitation: Observational exposure cannot establish causation or show that supplementation prevents dementia; residual confounding and reverse causation remain possible.
Supplement buyer’s guide
Evaluate the evidence on the label—not the confidence on the bottle.
We do not rank products before verifying labels, prices, testing documentation and conflicts. Start with the fields that make a comparison reproducible.
See the buyer’s guide →01Amount per serving
02Ingredient source
03Manufacturing method
04Other ingredients
05Third-party testing
06COA availability
07Cost per milligram
08Manufacturer transparency
09Return policy
10Subscription terms