Database/Preservative/Methylchloroisothiazolinone
100% petroleum · ISO 16128

Is Methylchloroisothiazolinone natural?

No. Same petrochemical isothiazolinone chemistry as methylisothiazolinone, with an added chlorine substituent.

INCI nameMethylchloroisothiazolinone
CAS26172-55-4
FormulaC4H4ClNOS · 149.60 Da
FunctionPreservative
FeedstockManufactured alongside methylisothiazolinone from petrochemical amide and sulfur…

How we scored it

Chlorinated isothiazolinone ring from petrochemical intermediates → 0/total = 0.0.
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 alongside methylisothiazolinone from petrochemical amide and sulfur intermediates, with an added chlorination step. No natural-origin route exists.

In plain English

A preservative, usually paired with methylisothiazolinone, that prevents microbial spoilage in cosmetic products. It is entirely synthesised from petrochemical feedstocks and does not occur in nature.

CosIng definition: Methylchloroisothiazolinone is the heterocyclic organic compound that conforms to the formula:

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Structure

2D structure of Methylchloroisothiazolinone

5-chloro-2-methyl-1,2-thiazol-3-one

PubChem CID 33344 ↗

References

  1. 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.
  2. 2Methylchloroisothiazolinone. PubChem CID 33344. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3METHYLCHLOROISOTHIAZOLINONE. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4METHYLCHLOROISOTHIAZOLINONE. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=METHYLCHLOROISOTHIAZOLINONE