Healthy aging
Cohort signals and animal findings; human intervention evidence is still developing.
Review the evidenceThe 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-ledReviewed 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.
Human research is developing. This guide shows where the science is promising—and where confident claims move beyond the evidence.
Read the complete explanation →Evidence snapshot
What the research can support today
Conservative editorial orientations based on the verified launch literature. Not clinical recommendations.
Cognitive health
Observational associations and one very small controlled pilot.
Review the evidenceCellular protection
Mechanistic evidence is substantial; clinical relevance is unresolved.
Review the evidenceCardiovascular research
No reliable controlled outcome evidence identified for clinical claims.
Review the evidenceMitochondrial function
Laboratory models support hypotheses, not proven human benefit.
Review the evidenceSleep research
An early controlled study needs independent replication.
Review the evidenceWhy 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
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.
Estimation and Validation of an Effective Ergothioneine Dose for Improved Sleep Quality Using a Physiologically Based Pharmacokinetic Model
- Intervention
- 5 or 10 mg/day in dose modeling; 8 mg/day vs placebo in validation
- Duration
- 8–16 weeks
Finding: The 8 mg/day validation study reported a statistically significant improvement in subjective sleep quality versus placebo.
Important limitation: Subjective outcome; linked modeling and validation design; replication by independent groups is needed.
Low Plasma Ergothioneine Predicts Cognitive and Functional Decline in an Elderly Cohort Attending Memory Clinics
- Intervention
- No intervention; baseline plasma ergothioneine
- Duration
- Up to 5 years
Finding: Lower baseline plasma ergothioneine was associated with poorer baseline performance and faster decline in several cognitive and functional measures.
Important limitation: Observational design cannot show that low ergothioneine caused decline or that supplementation would alter outcomes.
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