Ergothioneine — Supplements
Unique thiohistidine amino acid with a dedicated mammalian transporter (OCTN1); 2023 study found plasma ergothioneine inversely associated with all-cause and cardiovascular mortality in 2,763 Singaporeans over 20 years.
Overview
Ergothioneine (EGT) is a naturally occurring sulfur-containing amino acid and potent antioxidant synthesized exclusively by fungi (including culinary mushrooms) and certain bacteria — not by plants or animals. Humans cannot synthesize EGT but evolved a highly specific high-affinity transporter (OCTN1, encoded by SLC22A4) that actively concentrates EGT in tissues subject to oxidative stress: red blood cells, liver, kidney, lens of the eye, brain, seminal fluid, and mitochondria. This evolutionarily conserved, dedicated transporter has led researchers to propose that EGT functions as a 'longevity vitamin' — a nutrient for which chronic insufficiency contributes to age-related disease. In 2023, Halliwell et al. (Annals of the New York Academy of Sciences) published a prospective cohort study of 2,763 Singaporeans followed for 20 years, finding plasma ergothioneine levels were significantly and inversely associated with all-cause mortality, cardiovascular mortality, and cancer mortality — an independent predictor after adjusting for confounders. A 2021 study (Kalaras et al.) confirmed mushroom consumption is the primary dietary source, with EGT undetectable in non-mushroom diets. Two small human RCTs (Cheah et al., 2016 and 2017) showed EGT supplementation (25–30 mg/day) improved cognitive function and reduced inflammatory biomarkers in elderly subjects. Human interventional data is limited but growing.
Indications
- Longevity and all-cause mortality risk reduction (epidemiological evidence)
- Cognitive protection in aging
- Mitochondrial antioxidant support — concentrated in mitochondria
- Ocular health — EGT concentrates in the lens (cataract prevention potential)
- Ergothioneine insufficiency (populations with low mushroom intake)
Mechanism of Action
The SLC22A4-encoded transporter OCTN1 has extraordinarily high affinity for ergothioneine (Km ~17 µM) and actively concentrates it in tissues with high oxidative stress exposure: red blood cells (>mM concentrations), liver, kidney, mitochondria, and seminal fluid. This selective uptake — unique among dietary antioxidants — suggests evolutionary selection for EGT as a protective molecule in these specific compartments
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Ergothioneine (L-ergothioneine, pure) | 5–30 mg | Once daily | Human RCTs used 25–30 mg/day; dietary intake from mushrooms typically 1–5 mg/day; no established optimal dose |
Evidence Grade
GRADE C
Safety & Contraindications
- Excellent safety profile — consumed by humans for millennia through mushrooms; no reported toxicity in human studies
- Very limited clinical data on supplemental EGT in humans — two small RCTs (n<30 each); long-term supplemental safety data not established
- No known significant drug interactions
- Most effective in populations with low mushroom intake (EGT deficiency); benefit in regular mushroom consumers may be less pronounced
- Relatively expensive supplement — EGT is synthesized biotechnologically from fungi fermentation