The ingredient, explained

Ergothioneine

Selected evidence concerns in vitro.

Antioxidant

Explore connections

Ingredient guide

What it is and what it does

Ammonium, [1-carboxy-2--2-mercaptoimidazol-4-yl-ethyl]trimethyl-, hydroxide, inner salt, L--+--

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Antioxidant: Limits oxidation, including deterioration of formulation ingredients. This label alone does not show a clinical antioxidant effect in skin.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Laboratory research

L-ergothioneine reduced laboratory peroxide/free-radical endpoints and showed antioxidant activity in cultured fibroblasts.

What this does not tell us

Laboratory oxidation models and cell cultures. No human wrinkle, pigmentation or topical formulation efficacy is established.

Sources for this summary. PubMed 17760697 ↗

Research review checked Oct 1, 2026

Bounded review of 0 local candidate titles, selected relevant local abstracts, and targeted primary-source web searches. Not an exhaustive systematic review.