Ergothioneine
Also known as: ET, Ergothionein
A single small randomized controlled trial in older adults reported improved learning and stabilised neurofilament light chain after one year of intermittent 25 mg ergothioneine capsules. Acute oyster mushroom interventions showed reduced postprandial inflammatory markers but mixed cognitive findings. Observational cohort and meta-analytic data link higher mushroom intake to slightly lower all-cause mortality.
Last reviewed: 2026-10-14 · 5 indexed studies
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Overview
Ergothioneine is a diet-derived thiol antioxidant concentrated in mushrooms and available as an oral supplement. Human evidence is limited but includes a small year-long capsule trial in older adults and acute dietary studies with oyster mushroom, with signals for cognitive and anti-inflammatory effects.
Mechanism & Function
Mechanism of Action
Reviews of human and preclinical work describe ergothioneine as a selective, tissue-accumulating antioxidant transported by OCTN1 (SLC22A4), with proposed effects on oxidative stress, inflammation and cellular homeostasis relevant to ageing and neuroprotection.
Physiological Role
Acts as a circulating antioxidant that accumulates in tissues vulnerable to age-related oxidative decline; implicated in modulating inflammatory and cytoprotective responses.
Primary Pathways
Performance / Health Relevance
May be relevant to cognitive maintenance in older adults and to lowering acute inflammatory responses after mushroom consumption, but evidence is preliminary and heterogeneous.
Evidence Review
Practical Use & Dosage
- Minimum Effective Dose
- 25 mg taken three times per week (as used in a 1-year RCT)
- Optimal Range
- Not established
- Upper / Caution Level
- Not established
- Timing
- As administered in studies: intermittent capsule dosing (3×/week) or as dietary mushroom servings in acute studies
- Best Format
- Oral capsule or dietary mushroom sources
- Bioavailability
- Selective tissue uptake is mediated by the OCTN1 (SLC22A4) transporter, which influences accumulation in target tissues.
- Absorption Considerations
- Genetic variation in SLC22A4/SLC22A15 may affect tissue uptake and individual responses; clinical precision-nutrition approaches have been suggested.
Safety & Interactions
Side Effects
- •No treatment-related toxicity reported in the 1-year elderly trial
- •No acute adverse effects reported in the oyster mushroom study
Contraindications
- None established from the provided human studies
Drug Interactions
- •Not established from the provided abstracts
Who Should Avoid
- •Insufficient evidence for use in pregnancy, breastfeeding and certain clinical conditions; consult a clinician
Monitoring
No routine monitoring specified in the trials; monitor standard clinical safety labs if used long-term in older adults as done in the year-long trial.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Ergothioneine typically used or indicated?
Ergothioneine is most commonly used for: Healthy ageing, Cognitive support, General antioxidant support. Acts as a circulating antioxidant that accumulates in tissues vulnerable to age-related oxidative decline; implicated in modulating inflammatory and cytoprotective responses.
How does Ergothioneine work?
Reviews of human and preclinical work describe ergothioneine as a selective, tissue-accumulating antioxidant transported by OCTN1 (SLC22A4), with proposed effects on oxidative stress, inflammation and cellular homeostasis relevant to ageing and neuroprotection.
What is the recommended dose of Ergothioneine?
The optimal range is Not established. with a minimum effective dose of 25 mg taken three times per week (as used in a 1-year RCT). Best taken: As administered in studies: intermittent capsule dosing (3×/week) or as dietary mushroom servings in acute studies. Upper / caution level: Not established.
What are the side effects of Ergothioneine?
Reported side effects include: No treatment-related toxicity reported in the 1-year elderly trial; and No acute adverse effects reported in the oyster mushroom study. Monitoring: No routine monitoring specified in the trials; monitor standard clinical safety labs if used long-term in older adults as done in the year-long trial.
Does Ergothioneine interact with medications?
Known or theoretical interactions: Not established from the provided abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid Ergothioneine?
Ergothioneine is generally not recommended for: Insufficient evidence for use in pregnancy, breastfeeding and certain clinical conditions; consult a clinician; and None established from the provided human studies.
How strong is the evidence for Ergothioneine?
Evidence level: Moderate (overall score 68/100), based on 5 indexed studies on SuppIndex.
Research & References (5)
Investigating the efficacy of ergothioneine to delay cognitive decline in mild cognitively impaired subjects: A pilot study.
Double-blind RCT in older adults with mild cognitive impairment testing oral ergothioneine capsules (25 mg per capsule) taken three times weekly for one year compared with placebo.
A randomised controlled study to investigate the cognitive, mood, metabolic and anti-inflammatory effects of acute oyster mushroom intervention in healthy older adults.
Randomised crossover acute dietary study in healthy older adults consuming soups containing 0.5, 1 and 2 servings of oyster mushroom (rich in ergothioneine) and a calorie-matched control; outcomes assessed up to 6 hours post-consumption.
Prospective study of dietary mushroom intake and risk of mortality: results from continuous National Health and Nutrition Examination Survey (NHANES) 2003-2014 and a meta-analysis.
Prospective analysis of NHANES dietary recall data with meta-analysis of cohort studies examining associations between mushroom intake (a main dietary source of ergothioneine) and all-cause mortality.
The role of Ergothioneine in cognition and age-related neurodegenerative disease: a systematic review.
Systematic review focusing on ergothioneine's role in cognition and age-related neurodegenerative disease, synthesising preclinical and clinical literature up to 2025.
Ergothioneine as a potential geroprotector: Targeting molecular hallmarks of ageing and age-related diseases.
Systematic review framing ergothioneine as a candidate geroprotector, covering evidence from 2005–2025 and discussing pharmacokinetics via OCTN1 and potential to modulate hallmarks of ageing.
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Research Overview
Moderate EvidenceCite this ingredient
One-click citation export in APA, MLA, Chicago, BibTeX, or HTML. The URL below is stable and safe to link.
Stable URL
https://thesuppindex.com/ingredients/ergothioneine
SuppIndex. (2026). Ergothioneine: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/ergothioneine
Based on 5 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
No specific incompatibilities reported; commonly consumed alongside dietary sources (mushrooms) or as isolated oral supplements.