Database/Preservative/Thimerosal
Mostly petroleum · ISO 16128

Is Thimerosal natural?

Mostly not. Only the sodium counter-ion is natural mineral; the ethylmercury group and benzene-derived thiosalicylate ring are synthetic and organometallic.

INCI nameThimerosal
CAS54-64-8
FormulaC9H9HgNaO2S · 404.82 Da
FunctionPreservative
FeedstockThimerosal is synthesized from ethylmercuric chloride and sodium…

How we scored it

Na+ counter-ion natural (22.99 Da); ethylmercury-thiosalicylate anion (C9H9HgO2S, 381.83 Da) organometallic/benzene-derived, not on natural list → 22.99/404.82 = 0.06.
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

Thimerosal is synthesized from ethylmercuric chloride and sodium thiosalicylate, both petrochemical/organometallic intermediates with no natural production route. Only the sodium ion is mineral-derived.

In plain English

A synthetic organomercury preservative historically used in some cosmetics and vaccines. It is manufactured from petrochemical and mined-metal components, not from plants or renewable sources.

CosIng definition: Thimerosal is the metallo-organic compound that conforms to the formula:

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Structure

2D structure of Thimerosal

sodium (2-carboxylatophenyl)sulfanyl-ethylmercury

PubChem CID 16684434 ↗

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. 2Thimerosal. PubChem CID 16684434. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3THIMEROSAL. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4THIMEROSAL. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=THIMEROSAL