Is THIOHISTIDINE safe to use in EU cosmetics?

THIOHISTIDINE is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Always verify against the current official CosIng database before formulating.

What other records share CAS 2002-22-4?

CAS 2002-22-4 may appear across multiple EU annex records. The CAS lookup page shows all Annex II–VI entries sharing this identifier, useful for identifying cross-annex regulatory status of the same chemical substance.

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InventoryRef 8679815/10/2010

THIOHISTIDINE

1H-Imidazole-4-propanoic acid,α-amino-2,3-dihydro-2-thioxo; (S)-α-amino-2,3-dihydro-2-thioxo-1H-imidazole-4-propionic acid

THIOHISTIDINE is listed in the EU CosIng inventory, but no direct annex records are linked on this page yet.

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Regulatory evidence by market

No rule for this ingredient has been imported for any of the 13 markets tracked here.

That describes this inventory, not the law. No imported rule is not evidence that an ingredient is permitted: a rule may exist under another name or identifier, or in a dataset not yet imported here.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 2002-22-4

CAS 2002-22-4PubChem CID 2733604

(alphaS)-alpha-Amino-2,3-dihydro-2-thioxo-1H-imidazole-4-propanoic acid

IUPAC name: (2S)-2-amino-3-(2-sulfanylidene-1,3-dihydroimidazol-4-yl)propanoic acid

Molecular formula: C6H9N3O2S
Molecular weight: 187.22 g/mol
Exact mass: 187.04154771 Da
XLogP3: -3.6
Topological polar surface area: 119.0 Å²
Hydrogen-bond donors: 4
Hydrogen-bond acceptors: 4
Covalent units: 1
Defined stereocentres: 1

Also known as

L-ThiolhistidineMH6EDB26P8RefChem:4057682-Mercapto-L-histidineThiohistidine(S)-2-Amino-3-(2-thioxo-2,3-dihydro-1H-imidazol-4-yl)propanoic acidL-2-MercaptohistidineH-2-MERCAPTO-HIS-OH

16 more reported names

HISTIDINE, 2-MERCAPTO-, L-(2S)-2-amino-3-(2-sulfanyl-1H-imidazol-4-yl)propanoic acid1H-Imidazole-4-propanoic acid, alpha-amino-2,3-dihydro-2-thioxo-, (alphaS)-1H-IMIDAZOLE-4-PROPANOIC ACID, .ALPHA.-AMINO-2,3-DIHYDRO-2-THIOXO-, (S)-UNII-MH6EDB26P8EINECS 217-899-2(S)-2-Mercaptohistidine(S)-alpha-Amino-2,3-dihydro-2-thioxo-1H-imidazole-4-propionic acidL-2-THIOXOHISTIDINETHIOHISTIDINE [INCI]GLXC-256442-Mercapto-L-histidine, AldrichCPR(|AS)-|A-Amino-2,3-dihydro-2-thioxo-1H-Imidazole-4-propanoic AcidEBC-64035(2S)-2-Azaniumyl-3-(2-sulfanylidene-1,3-dihydroimidazol-4-yl)propanoate2-THIOLHISTIDINE L-FORM [MI]

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

EPA DTXSID:DTXSID401021728

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Inventory details for THIOHISTIDINE

INCI name

THIOHISTIDINE

Description

1H-Imidazole-4-propanoic acid,α-amino-2,3-dihydro-2-thioxo; (S)-α-amino-2,3-dihydro-2-thioxo-1H-imidazole-4-propionic acid

Record provenance

Inventory reference: 86798
Imported identity: THIOHISTIDINE
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for THIOHISTIDINE

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Key data

CAS

2002-22-4

217-899-2

Restriction

—

Function

ANTIOXIDANT: Inhibiting reactions promoted by oxygen, thus avoiding oxidation and rancidity.
BLEACHING: Bleaching or lightening the shade of hair and/or skin.
CHELATING: Forming complexes with metal ions which could affect the stability and/or appearance of cosmetics.

Official EU ingredient-name evidence

The ingredient name exactly matches the official 2025 EU glossary of common ingredient names.

#28765 · THIOHISTIDINE

Ingredients with overlapping formulation functions

TETRASODIUM HYDROXY IMINODISUCCINATECHELATING

TETRASODIUM IMINODISUCCINATECHELATING

TETRASODIUM PYROPHOSPHATEANTICAKING, BUFFERING, CHELATING, ORAL CARE

TEUPOLIOSIDEANTIOXIDANT, BLEACHING, CHELATING, SKIN PROTECTING

TITANIUM TETRAGLYCEROXIDECHELATING, HUMECTANT, ORAL CARE, SKIN CONDITIONING

TRIETHYLENETETRAMINE HCLCHELATING

TRIMETHOXYBENZYLIDENE PENTANEDIONEANTIOXIDANT, CHELATING, SKIN PROTECTING

TRIMETHYLDECENEDIONEBLEACHING, CHELATING

Additional official and scientific sources

11 external databases to check this identity in

Each link searches that source for this identity. What each source is, and its legal weight

ECHA CHEM / Information on chemicals PubChem PUG REST EU Safety Gate cosmetic product alerts ECHA CHEM US EPA CompTox Cosmetic Ingredient Review safety assessments FDA Global Substance Registration System ILO/WHO International Chemical Safety Cards Japan NITE-CHRIP NIOSH Pocket Guide to Chemical Hazards OECD eChemPortal

How THIOHISTIDINE appears in the CosIng inventory

The CosIng inventory lists THIOHISTIDINE as a cosmetic ingredient and this page links it to 0 annex records. The inventory entry captures names and identifiers, while the annex records show where the substance is prohibited, restricted or positively listed in EU cosmetics law.

THIOHISTIDINE is also tagged with 3 cosmetic functions in the official data. Function labels describe intended use, but they do not replace regulatory review of linked annex records before formulation or labelling work.

Frequently asked questions

THIOHISTIDINE is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Absence of an annex link does not guarantee unrestricted use — always verify against the current official CosIng database before formulating.

According to the EU CosIng inventory, THIOHISTIDINE carries the following function designation(s):

CAS 2002-22-4 may appear across multiple EU annex records. Viewing the CAS lookup page shows all Annex II–VI entries sharing this identifier, which is useful for identifying cross-annex regulatory status of the same chemical substance.

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Source note for THIOHISTIDINE

This page reproduces the CosIng inventory entry for THIOHISTIDINE from public European Commission cosmetic ingredient materials and shows linked identifiers even when no direct annex match is currently attached.

Use this inventory page to research THIOHISTIDINE and compare linked records, but verify restrictions and legal status against the current official source text and law before making regulatory decisions.

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Tools & next steps

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