L-Ergothioneine

What is L-Ergothioneine?

L-Ergothioneine is a sulfur-containing derivative of the amino acid histidine, known chemically as (2S)-3-(2-sulfanylidene-4,5-dihydro-1H-imidazol-5-yl)-2-(trimethylazaniumyl)propanoate. It occurs naturally at high levels in edible mushrooms like oyster and shiitake, produced by select soil bacteria and mycobacteria. Humans selectively uptake it through the OCTN1 transporter and accumulate it in mitochondria-dense tissues, including skin cells prone to stress. In cosmetics, it belongs to skin conditioning and antioxidant categories, typically added to serums, creams, and sunscreens at trace levels. It functions by directly neutralizing reactive oxygen species and peroxynitrite, offering superior stability compared to many other antioxidants, thus aiding cellular protection without pro-oxidant risks.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →

Benefits

Delivers targeted antioxidant activity to combat free radicals.

Supports skin cell resilience under environmental stress.

Enhances formulation stability as a reliable protective agent.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals frequently exposed to urban pollution or sunlight.
Anyone with known hypersensitivity to mushroom-derived compounds.
Those seeking antioxidant support in daily routines.
Those preferring to avoid novel bioactives entirely.
People with skin showing early oxidative stress signs.
Individuals with untested allergies to thiols.

Safety Notes

  • Rated low hazard by safety assessments with no significant concerns.
  • Non-comedogenic, suitable for acne-prone skin types.

Frequently Asked Questions about L-Ergothioneine

What is L-Ergothioneine sourced from?

Primarily from mushrooms like shiitake and oyster, where it concentrates naturally.

Is L-Ergothioneine safe for daily use?

Yes, it carries a low safety rating from authoritative reviews, with minimal risks.

How does it differ from vitamin antioxidants?

It targets specific oxidants like peroxynitrite and remains highly stable in formulas.