Is THIOXANTHINE safe to use in EU cosmetics?

THIOXANTHINE 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 261-31-4?

CAS 261-31-4 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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Use the INCI Checker to screen a full ingredient list across selected markets, or use the substance market comparison to review this identity across all supported market datasets.

InventoryRef 3859315/10/2010

THIOXANTHINE

10H-Dibenzo[b,e]thiin

THIOXANTHINE 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 261-31-4

CAS 261-31-4PubChem CID 67495

Thioxanthene

9H-thioxanthene is a thioxanthene that consists of a xanthene skeleton in which the oxygen atom is replaced by a sulfur atom. — ChEBI

IUPAC name: 9H-thioxanthene

Molecular formula: C13H10S
Molecular weight: 198.29 g/mol
Exact mass: 198.05032149 Da
XLogP3: 3.9
Topological polar surface area: 25.3 Å²
Hydrogen-bond donors: 0
Hydrogen-bond acceptors: 1
Covalent units: 1
Defined stereocentres: 0

Also known as

ThioxanthineThiaxantheneThiaxanthenUNII-1J3P67894AEINECS 205-972-1THIOXANTHENE [MI]1J3P67894ACHEBI:51055

16 more reported names

RefChem:189677THIOXANTHINE [INCI]CHEBI:51056205-972-1InChI=1/C13H10S/c1-3-7-12-10(5-1)9-11-6-2-4-8-13(11)14-12/h1-8H,9HPQJUJGAVDBINPI-UHFFFAOYSA-NThioxanthenDibenzothiapyran10H-Dibenzo(b,e)thiin10H-dibenzo[b,e]thiinMetixene EP Impurity A9H-thioxanthenThioxanthene CRS10H-dibenzo[b,e]thiopyranSCHEMBL8717Metixene Hydrochloride EP Impurity A

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:51055
ChEMBL:CHEMBL79451
EPA DTXSID:DTXSID20180732
PubMed:22719586
PubMed:22593663
PubMed:22565647
PubMed:22292096
PubMed:22151628
PubMed:22091101
PubMed:22091049
PubMed:22090935
PubMed:21836703
PubMed:21060765
PubMed:20679741
PubMed:20450924

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 THIOXANTHINE

INCI name

THIOXANTHINE

Description

10H-Dibenzo[b,e]thiin

Record provenance

Inventory reference: 38593
Imported identity: THIOXANTHINE
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for THIOXANTHINE

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Key data

CAS

261-31-4

205-972-1

Restriction

—

Function

ANTIOXIDANT: Inhibiting reactions promoted by oxygen, thus avoiding oxidation and rancidity.
HAIR CONDITIONING: Enhancing the appearance and feel of hair. Leaving the hair easy to comb, supple, soft and shiny and/or imparting volume, lightness, gloss, texture, etc.

Official EU ingredient-name evidence

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

#28772 · THIOXANTHINE

Ingredients with overlapping formulation functions

THIOLACTIC ACIDANTIOXIDANT, DEPILATORY, FRAGRANCE, HAIR WAVING OR STRAIGHTENING, REDUCING

THIOMORPHOLINONEANTIOXIDANT, SKIN CONDITIONING

THIOSALICYLIC ACIDANTIOXIDANT, KERATOLYTIC, REDUCING

THIOTAURINEANTIOXIDANT

THRAUSTOCHYTRIUM SP. ATCC 26185 OILANTIOXIDANT, HUMECTANT, SKIN CONDITIONING, SKIN CONDITIONING - EMOLLIENT

THUJA KORAIENSIS EXTRACTANTIOXIDANT, SKIN CONDITIONING

THUJA OCCIDENTALIS LEAF EXTRACTANTIOXIDANT, BLEACHING, HAIR CONDITIONING, PERFUMING, SKIN CONDITIONING

THUJA OCCIDENTALIS LEAF/STEM EXTRACTANTIOXIDANT

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 THIOXANTHINE appears in the CosIng inventory

The CosIng inventory lists THIOXANTHINE 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.

THIOXANTHINE is also tagged with 2 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

THIOXANTHINE 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, THIOXANTHINE carries the following function designation(s):

CAS 261-31-4 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 THIOXANTHINE

This page reproduces the CosIng inventory entry for THIOXANTHINE 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 THIOXANTHINE 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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