EWG level: 2
This is used an inorganic sulfur-based salt used as a preservative. Sodium Sulfite is referred to as sulfiting agents because they release sulfur dioxide under certain conditions. In cosmetics and personal care products, these ingredients are used in the formulation of permanent waves, hair bleaches, hair dyes, colors and tints, and in some bath and skin care products. Sodium Sulfite function as reducing agents, which means they donate hydrogen molecules to other substances in cosmetics and personal care products and also as antioxidants preventing or slowing deterioration of cosmetics and personal care products caused by chemical reactions with oxygen. With the exception of Sodium Metabisulfite, these ingredients also modify hair fibers to facilitate changes to the structure of the fibers, such as with permanent waves or with hair straightening.
Its functions are: Antioxidant; Hair-waving/Straightening Agent; Reducing Agent; Hair Waving or Straightening; Preservative.
No ecological concerns, “designed as safe for general or specific, limited use in food” (FDA Food Additive Status)
“Classified as not expected to be potentially toxic or harmful” (Environment Canada Domestic Substance List)
“Limited evidence of immune system toxicity or allergies” (National Library of Medicine HazMap)