Ergothioneine

ergothioneine · EGT

A mushroom-derived antioxidant proposed as a possible 'longevity vitamin'.

TypeSupplement / dietary

The grade answers: What does the human evidence support for: Cellular antioxidant / "longevity vitamin"?

Grade

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class: Amino acid antioxidant
Primary use: Cellular antioxidant / "longevity vitamin"
Evidence strength: low
Last reviewed: 2026-07-01

Bottom line

Genuinely interesting: the body has a dedicated transporter for it, and lower blood levels track with worse aging outcomes. But that's association — no trial yet shows that taking it changes anything.

What the evidence says

Ergothioneine is unusual because human cells express a specific transporter (OCTN1) that concentrates it in tissues under oxidative stress — a strong hint the body values it, which is why some researchers call it a candidate 'longevity vitamin'. Observational studies link lower blood ergothioneine to higher cardiovascular and mortality risk and cognitive decline. What's missing is interventional proof: no randomized trial has shown that supplementing it improves outcomes. Grade C: compelling biology and epidemiology, zero outcome trials.

Key studies

[1]
Ergothioneine blood levels and mortality/cardiometabolic risk · observational
Lower levels associated with worse outcomes — not causal.
Open on PubMed ↗
[2]
Ergothioneine as a longevity vitamin (review) · review
Argues the case from transporter biology and epidemiology.
Open on PubMed ↗
[3]
Ergothioneine and cognitive aging · observational
Associations with cognition; interventional data absent.
Open on PubMed ↗

See all studies on PubMed ↗

Mechanism

A potent, stable antioxidant selectively accumulated by cells via the OCTN1 transporter, concentrating in mitochondria and tissues exposed to oxidative stress; dietary sources are chiefly mushrooms.

Safety

Appears very safe in the limited human data, with high tolerability; long-term supplementation safety is not yet well characterised.

Dosage context

Dietary intake varies with mushroom consumption; supplement trials are few and doses not standardised. Because the evidence is associational, an 'optimal' dose is undefined.

Examples of application

Obtained mainly from mushrooms in the diet.
Supplement doses aren't standardised, since evidence is associational.
A 'watch this space' longevity candidate, not a proven one.

From the field

Ergothioneine is the most interesting molecule here with the least interventional proof: a dedicated transporter and strong associations, but nobody has yet shown that a pill helps. Grade C, and one of the more honest 'watch this space' entries.

Related molecules

N-Acetylcysteine (NAC)C TaurineC

How we assign grades → Method