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Sodium Sulfite
Sodium SulfiteAntioxidant
An antioxidant that protects the formula, with no evidence it helps skin. Perms and straighteners use it to reshape hair.
What it does
It reacts with oxygen before fragile ingredients can, so they keep their color and strength. In hair products it helps break the bonds that hold hair’s shape.
The EU’s ingredient database lists it as an antioxidant (slows reactions with oxygen, like going rancid).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗
The evidence, graded
expert consensusUS safety reviewers assessed sodium sulfite with related sulfite salts (final report published 2003), noting it works in cosmetics as a reducing agent, a hair-waving and straightening agent and an antioxidant. In clinical tests sodium sulfite didn’t irritate skin or cause allergy, though these sulfites may cause reactions in patch tests on people seen by skin doctors. The reviewers judged them safe as used, and confirmed that in 2023.Nair 2003 · International Journal of Toxicology ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
Also known as
sodium sulphite
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