Ergothioneine
Antioxidant ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Ergothioneine is a naturally occurring sulfur-containing amino acid derivative (a betaine of 2-mercaptohistidine) synthesized by fungi and certain bacteria but not by humans, who must obtain it from the diet. It is taken up and concentrated in cells via a dedicated transporter (OCTN1/SLC22A4), accumulating in tissues with high oxidative load such as mitochondria, liver, kidney, red blood cells and the lens of the eye. Because of its selective retention and stability, it has been proposed as a diet-derived cytoprotective compound, sometimes informally called a 'longevity vitamin.'
Exploratory record, not a reviewed medical publication.
See the editorial and medical-review policies for the publication gate.
This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Ergothioneine is an antioxidant most often used for may reduce oxidative stress and protect cells from free-radical damage, associated in observational data with healthier aging and lower risk of cardiometabolic disease, may support mitochondrial protection. NutriStack rates the overall evidence as emerging. A typical adult dose is 5-30 mg per day in studies; no established RDA, commonly taken as l-ergothioneine (naturally derived or fermentation-produced), taken orally. This profile indexes 10 sources.
- May reduce oxidative stress and protect cells from free-radical damage1,10
- Associated in observational data with healthier aging and lower risk of cardiometabolic disease7,8
- May support mitochondrial protection6
- Investigated for cognitive and neuroprotective support
- May help protect against UV- and inflammation-related cellular damage1,6
- Generally well tolerated in studies with no consistent adverse effects reported
- Possible mild gastrointestinal discomfort at higher intakes (not well characterized)
- Insufficient safety data in pregnancy and breastfeeding; avoid supplementation
- Insufficient data in children
- Consult a clinician before use if you have a serious medical condition or take other medications
The bottom line
Evidence rating emerging. Most-documented uses: may reduce oxidative stress and protect cells from free-radical damage, associated in observational data with healthier aging and lower risk of cardiometabolic disease, may support mitochondrial protection. 10 sources indexed (2005–2020), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Ergothioneine exists predominantly in its stable thione tautomer at physiological pH, which makes it resistant to autoxidation and gives it a long intracellular half-life compared with other thiols such as glutathione. It is actively imported into cells by the organic cation transporter novel type 1 (OCTN1, encoded by SLC22A4), allowing it to concentrate in specific tissues and subcellular compartments including mitochondria. Functionally it scavenges reactive oxygen and nitrogen species (including hydroxyl radical, peroxynitrite and singlet oxygen), chelates divalent transition metals such as copper that would otherwise catalyze oxidative reactions, and helps maintain cellular redox balance. These actions are associated with reduced lipid peroxidation, protection of mitochondrial function, and dampening of inflammatory signaling, though the precise downstream pathways in humans remain under investigation.7,1
Dosing & protocol.
Water soluble and absorbed via the OCTN1 transporter in the intestine; tissue uptake is transporter-mediated and slow, so it accumulates over weeks of regular intake rather than acting acutely. Can be taken with or without food.1
What it actually costs.
Real-world pricing across three quality tiers. Assumes L-Ergothioneine (purified, 5-15 mg per serving).
Ergothioneine is one of the more expensive antioxidants because purified material is costly to produce; budget options are usually lower-dose mushroom extracts, while branded fermentation-derived grades sit at the premium end. Prices reflect typical US retail per effective daily dose of 5-15 mg. Whole-food mushroom sources are cheaper per gram of mushroom but deliver smaller, more variable ergothioneine amounts. Updated 2026-06-04.
Full safety detail.
Side effects
- Generally well tolerated in studies with no consistent adverse effects reported
- Possible mild gastrointestinal discomfort at higher intakes (not well characterized)
Contraindications
- Insufficient safety data in pregnancy and breastfeeding; avoid supplementation
- Insufficient data in children
- Consult a clinician before use if you have a serious medical condition or take other medications
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Randomized controlled trials
2- 1Administration of pure ergothioneine to healthy human subjects: uptake, metabolism, and effects on biomarkers of oxidative damage and inflammationCheah IK et al. · Antioxidants and Redox Signaling · 2017
Oral ergothioneine was well absorbed and strongly retained in the body, with trends toward reduced biomarkers of oxidative stress and inflammation.
- 2Pharmacokinetics of L-Ergothioneine, a Dietary Antioxidant, in Healthy Human VolunteersSource linkedDOICheah IK, Tang RMY, Yew TSZ, Lim KHC, Halliwell B · Antioxidants and Redox Signaling · 2017
Reviews & position papers
5- 3Could Ergothioneine Aid in the Treatment of Coronavirus Patients?Source linkedDOICheah IK, Halliwell B · Antioxidants · 2020
- 4Could ergothioneine aid in the treatment of coronavirus patients? / Ergothioneine as a longevity vitaminHalliwell B, Cheah IK, Tang RMY · FEBS Letters · 2018
Argued that ergothioneine meets criteria for a longevity vitamin, with low body levels linked to accelerated aging phenotypes and chronic disease.
- 5Ergothioneine, recent developmentsSource linkedDOIHalliwell B, Cheah IK, Tang RMY · Redox Biology · 2018
- 6Ergothioneine, an adaptive antioxidant for the protection of injured tissues? A hypothesisSource linkedDOICheah IK, Halliwell B · Biochemical and Biophysical Research Communications · 2017
- 7Ergothioneine - a diet-derived antioxidant with therapeutic potentialCheah IK, Halliwell B · FEBS Letters · 2012
Reviewed evidence that ergothioneine accumulates in tissues exposed to oxidative stress and proposed it as a physiological cytoprotectant obtained from the diet.
Observational studies
2- 8Plasma ergothioneine and the risk of cardiovascular disease, all-cause mortality and cardiovascular mortalitySmith E et al. · Heart · 2020
In a prospective cohort, higher blood ergothioneine levels were associated with reduced risk of cardiovascular events and lower all-cause and cardiovascular mortality.
- 9Low levels of ergothioneine, a dietary antioxidant, predict risk for cardiovascular and all-cause mortality (PIVUS cohort)Source linkedDOISmith E, Ottosson F, Hellstrand S, Ericson U, Orho-Melander M, Fernandez C, Melander O · Heart · 2020
Reference material
1- 10Discovery of a physiological role for the transporter OCTN1 in the uptake of ergothioneineGrundemann D et al. · Proceedings of the National Academy of Sciences of the USA · 2005
Identified OCTN1 as a high-affinity ergothioneine transporter, establishing a dedicated cellular uptake pathway and supporting a physiological function for dietary ergothioneine.
Common questions.
Quick answers about Ergothioneine, drawn from the data on this page.
What is Ergothioneine?
Ergothioneine is a naturally occurring sulfur-containing amino acid derivative (a betaine of 2-mercaptohistidine) synthesized by fungi and certain bacteria but not by humans, who must obtain it from the diet. It is taken up and concentrated in cells via a dedicated transporter (OCTN1/SLC22A4), accumulating in tissues with high oxidative load such as mitochondria, liver, kidney, red blood cells and the lens of the eye. Because of its selective retention and stability, it has been proposed as a diet-derived cytoprotective compound, sometimes informally called a 'longevity vitamin.'
What is Ergothioneine used for?
Commonly cited benefits of Ergothioneine include: May reduce oxidative stress and protect cells from free-radical damage; Associated in observational data with healthier aging and lower risk of cardiometabolic disease; May support mitochondrial protection; Investigated for cognitive and neuroprotective support; May help protect against UV- and inflammation-related cellular damage. NutriStack rates the overall evidence as emerging.
What is a typical dose of Ergothioneine?
A typical adult dose of Ergothioneine is 5-30 mg per day in studies; no established RDA. The commonly recommended form is L-ergothioneine (naturally derived or fermentation-produced), taken orally. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Ergothioneine?
Reported side effects include generally well tolerated in studies with no consistent adverse effects reported, possible mild gastrointestinal discomfort at higher intakes (not well characterized). This is educational information; check with a healthcare professional before use.
How strong is the evidence for Ergothioneine?
NutriStack rates this as Emerging, meaning early RCT signal, mechanistic data, or limited human evidence. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
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