How we scored it
Inorganic mineral salt Na2S2O5 from sulfur dioxide + sodium carbonate, both mineral feedstocks → total/total = 1.0.
What counts. ISO 16128-2 scores the atoms that remain in the final ingredient. Reagents, solvents, catalysts and protecting groups used during manufacture leave no mass behind and are not counted.
Where it comes from
Manufactured by absorbing sulfur dioxide, produced from mineral sulfur or metal-sulfide roasting, into sodium carbonate solution. Both feedstocks are mineral, not petrochemical.
In plain English
An antioxidant and preservative that stops products discolouring and protects fragrance and active ingredients from oxidation. It is a mineral salt manufactured from sulfur dioxide and soda, both inorganic feedstocks.
CosIng definition: Sodium Metabisulfite is the inorganic salt that conforms to the formula:
Structure
References
- 1ISO 16128-1:2016 and ISO 16128-2:2017 — Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products. ISO, Geneva.
- 2Sodium Metabisulfite. PubChem CID 656671. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
- 3SODIUM METABISULFITE. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
- 4SODIUM METABISULFITE. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=SODIUM%20METABISULFITE