From mushrooms (especially oyster and shiitake) or as a supplement.
Higher levels are associated with less cardiovascular disease and decline; no trials.
View the study (cohorts) →⏱ 3 min read
Ergothioneine is a peculiar sulfur-containing amino acid with exceptional properties in human biology: the body cannot synthesize it (only certain fungi and bacteria produce it), but human cells express a specific high-affinity transporter (OCTN1 or SLC22A4) that selectively takes it up from the bloodstream and concentrates it in tissues with high oxidative stress (bone marrow, lens of the eye, erythrocytes, liver, semen), a specific tissue distribution that points to a biological role distinct from that of simple circulating antioxidants and that has generated growing interest in nutrition and aging research.
Unlike most dietary antioxidants (vitamin C, vitamin E, polyphenols), which are general-purpose neutralizers with a short plasma half-life, ergothioneine has an exceptionally long half-life (about one month), accumulates intracellularly at very stable concentrations, and resists practically without degradation under chemical conditions that would destroy other antioxidants (heat, acidic pH, severe oxidation); these properties have led to the hypothesis that it could be an "oxidative stress vitamin" or "aging vitamin" whose adequate intake would be relevant for maintaining mitochondrial integrity and long-term cellular function.
The most concentrated dietary sources of ergothioneine are edible mushrooms: oyster mushrooms (Pleurotus), shiitake, maitake, lion's mane, and reishi contain the highest amounts (between 0.5 and 7 mg per usual 100 g serving), followed by cremini and portobello mushrooms (more modest amounts); it is also present in very small amounts in other foods derived indirectly from transfer through the animal diet (egg yolk, liver, organ meats); typical Western diets provide low amounts (around 1-2 mg/day), significantly lower than traditional diets with more frequent mushroom consumption, such as the Japanese diet.
An influential hypothesis proposed by Ames's group (2017) suggests that ergothioneine could be a "longevity vitamin" whose subclinical deficiency would contribute to accelerated cellular aging; epidemiological studies associate low plasma ergothioneine levels with higher cardiovascular and all-cause mortality in cohorts of older adults, an association that, together with preclinical data in animal models, motivates ongoing clinical trials to evaluate whether specific supplementation can provide benefits for cognitive function, cardiovascular health, or longevity.
In older adults, several observational studies have correlated low plasma ergothioneine levels with a higher risk of mild cognitive impairment and dementia; the Singapore epidemiological study published in 2016 documented that regular mushroom consumption (two servings a week) was associated with significant reductions in the incidence of mild cognitive impairment, an association partly attributable to ergothioneine among other components; intervention trials with specific supplementation are still preliminary.
Regarding cardiovascular profile and oxidative stress markers, several small studies have documented favorable correlations between plasma ergothioneine levels and markers of cardiovascular health, along with reductions in systemic oxidative markers with regular mushroom consumption; intervention trials with specific supplementation for cardiovascular indications are still limited.
The most accessible and affordable source is regular consumption of edible mushrooms, especially oyster, shiitake, and maitake mushrooms; a 100 g serving of cooked oyster mushrooms several times a week can contribute significantly to the body's ergothioneine pool; the specific supplements marketed with isolated ergothioneine (typically 5-30 mg/dose) are a more expensive option with a clinical basis that is still preliminary; effects on cellular markers appear gradually, and supplementation for weeks to months is necessary to reach stable plasma levels.
It is one of the compounds with the most exceptional documented safety profile: practically no adverse effects have been described at the dietary and supplemental doses studied, with several years of exposure and no significant toxicities reported; people with a mushroom allergy may have cross-reactions with supplements derived from fungal sources; data on specific supplementation in pregnancy and breastfeeding are limited, although habitual dietary consumption of mushrooms as food is safe; pure commercial products with pharmaceutical-grade ergothioneine are still becoming established on the market and prices are significantly higher than for other antioxidants; the reasonable position is to prioritize regular dietary consumption of mushrooms as an accessible and sustainable strategy to optimize intake; specific supplements may have a place in clinical research or in people with very low dietary mushroom consumption who want to optimize their intake of this compound with a promising clinical profile.
Information, not medical advice. Scientific evidence reflects the quality of the studies.