What it is
Ergothioneine is a betaine derivative of the amino acid histidine that contains a sulfur group and is found naturally in mushrooms and certain other organisms. In skincare it is valued as a stable antioxidant ingredient that helps protect the formula and condition the skin. It is used in sunscreens and antioxidant-focused products, typically at low concentrations.
Safety & warnings
Ergothioneine is generally well tolerated, water soluble, and not associated with comedogenicity or common allergen concerns at typical use levels.
Origin & sourcing
Naturally occurring; concentrated in mushrooms and some bacteria and fungi. Cosmetic-grade material is commonly produced by fermentation or biosynthesis.
History
Ergothioneine was first identified in the early twentieth century from ergot fungus, which gives the compound its name. It later attracted interest as a dietary and topical antioxidant.
Questions everyone asks
Where does ergothioneine come from?
It occurs naturally, with mushrooms being a notable source; cosmetic material is often made by fermentation.
What is its role in a sunscreen?
It functions as an antioxidant and skin-conditioning ingredient, not as a sun filter.