Ingredient library
Sodium metabisulfite (sulfite antioxidant)
INCI: Sodium Metabisulfite
An antioxidant stabiliser that protects the oxidation-sensitive botanical bioactives (part of the Redensyl-style system) from degrading in the water base.
Evidence and limitations
Established cosmetic-science consensus as an antioxidant stabiliser; note that sulfites can be sensitising for some people, which is distinct from the sulfates this formula is free from.