What does the restriction note for UROCANIC ACID mean?

The restriction field for UROCANIC ACID reads: II/418. This is the restriction note from the CosIng inventory. For authoritative conditions and limits, always refer to the linked annex entries.

What other records share CAS 104-98-3?

CAS 104-98-3 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.

How do I check if my formula contains UROCANIC ACID?

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 8461315/10/2010

UROCANIC ACID

2-Propenoic acid, 3-(1H-imidazol-4-yl)-

UROCANIC ACID is linked to 1 EU annex record on this page. Inventory note: II/418.

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Regulatory evidence by market

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Market	Evidence status	Records	Source language
European Union	Evidence linked Prohibited entry found Open this evidence	1	English and EU languages
Great Britain	Evidence linked Prohibited Open this evidence	1	English
Canada	Evidence linked Prohibited Open this evidence	1	English and French
New Zealand	Evidence linked Prohibited Open this evidence	1	English
ASEAN	Evidence linked Prohibited Open this evidence	1	English and national languages
China	Evidence linked Prohibited Open this evidence	1	Chinese with selected English material
Japan	Source mapped Official source mapped; ingredient rule not imported	0	Japanese; official English translation available
South Korea	Evidence linked Prohibited Open this evidence	1	Korean with some English names
United States	Source mapped Official source mapped; ingredient rule not imported	0	English
Australia	Source mapped Official source mapped; ingredient rule not imported	0	English
Brazil	Evidence linked Prohibited Open this evidence	1	Portuguese with INCI crosswalks
India	Evidence linked Prohibited Open this evidence	1	English and Hindi
Saudi Arabia	Source mapped Official source mapped; ingredient rule not imported	0	Arabic and English

Chemical identity and properties

PubChem 2D chemical structure for CAS 104-98-3

CAS 104-98-3PubChem CID 736715

Urocanic Acid

Urocanic acid is an alpha,beta-unsaturated monocarboxylic acid that is prop-2-enoic acid substituted by a 1H-imidazol-4-yl group at position 3. It is a metabolite of hidtidine. It has a role as a chromophore and a human metabolite. It is a member of imidazoles and an alpha,beta-unsaturated monocarboxylic acid. It is a conjugate acid of a urocanate. — ChEBI

IUPAC name: (E)-3-(1H-imidazol-5-yl)prop-2-enoic acid

Molecular formula: C6H6N2O2
Molecular weight: 138.12 g/mol
Exact mass: 138.042927438 Da
XLogP3: 0.0
Topological polar surface area: 66.0 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 3
Covalent units: 1
Defined stereocentres: 0

Also known as

Urocaninic acid(2E)-3-(1H-imidazol-4-yl)prop-2-enoic acid3-(1H-Imidazol-4-yl)-2-propenoic acid2-Propenoic acid, 3-(1H-imidazol-4-yl)-G8D26XJJ3BNSC-663572-Propenoic acid, 3-(1H-imidazol-4-yl)-, (E)-CHEBI:27248

16 more reported names

Acid, UrocanicGlyoxalinylacrylic AcidAcid, GlyoxalinylacrylicRefChem:901492203-258-43-(1H-imidazol-5-yl)prop-2-enoic acidtrans-Urocanic acid4-imidazoleacrylic acid3465-72-3urocanateimidazoleacrylic acid(E)-3-(1H-imidazol-5-yl)acrylic acid5-Imidazoleacrylic acid(2E)-3-(1H-IMIDAZOL-4-YL)ACRYLIC ACID(E)-3-(4-Imidazolyl)acrylic acid3-Imidazol-4-ylacrylic acid

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:27248
ChEBI:CHEBI:30817
ChEMBL:CHEMBL1236602
EPA DTXSID:DTXSID5041148
PubMed:24061166
PubMed:15337293
PubMed:14617103

Evidence from additional scientific databases

NIH PubChem PUG-View

Exact identifier match736715

Attributed physical-property, hazard, environmental and use annotations.

Melting Point: 225 °C Source: DrugBank
Melting Point: 225 °C Source: Human Metabolome Database (HMDB)

Physical Description: Solid Source: Human Metabolome Database (HMDB)

Solubility: 1500 mg/L (at 17 °C) Source: DrugBank
Solubility: 1.5 mg/mL at 17 °C Source: Human Metabolome Database (HMDB)

Cosmetic Ingredient Review Conclusion: The safety of this ingredient has not been documented and substantiated. The CIR Expert Panel cannot conclude whether Urocanic Acid is safe for use in cosmetic products until such time as the appropriate safety data have been obtained and evaluated. Source: Cosmetic Ingredient Review (CIR)
Cosmetic Ingredient Review Finding(s): Ingredients for which the data are insufficient and their use in cosmetics is not supported Source: Cosmetic Ingredient Review (CIR)

Cosmetic Ingredient Review Link: CIR ingredient: Urocanic Acid Source: Cosmetic Ingredient Review (CIR)

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status

Source	Result	Checked
EMBL-EBI ChEBI	Needs review	2026-08-31
NIH PubChem PUG-View	Exact match	2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Inventory details for UROCANIC ACID

INCI name

UROCANIC ACID

Description

2-Propenoic acid, 3-(1H-imidazol-4-yl)-

Record provenance

Inventory reference: 84613
Imported identity: UROCANIC ACID
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for UROCANIC ACID

Annex II Restriction reference

Entry 418

3-Imidazol-4-ylacrylic acid (Urocanic acid) and its ethyl ester

CAS: 27538-35-8 / 104-98-3

EC: 248-515-1 / 203-258-4

Key data

CAS

104-98-3

203-258-4

Restriction

II/418

Function

UV ABSORBER: Protecting the cosmetic product from the effects of UV-light.

Official EU ingredient-name evidence

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

#29691 · UROCANIC ACID

Ingredients with overlapping formulation functions

TRIMETHYLSILYL CELLULOSEFILM FORMING; HAIR FIXING; HAIR WAVING OR STRAIGHTENING; UV ABSORBER; VISCOSITY CONTROLLING

TRIPABA PANTHENOLANTISTATIC, HAIR CONDITIONING, UV ABSORBER

TRIS(TETRAMETHYLHYDROXYPIPERIDINOL) CITRATEUV ABSORBER

TRIS-BIPHENYL TRIAZINELIGHT STABILIZER, UV ABSORBER, UV FILTER

VA/CROTONATES/METHACRYLOXYBENZOPHENONE-1 COPOLYMERFILM FORMING, HAIR FIXING, UV ABSORBER

VITIS VINIFERA SEED EXTRACTANTI-SEBORRHEIC, ANTIMICROBIAL, ANTIOXIDANT, ORAL CARE, SKIN PROTECTING, UV ABSORBER

ZINC ADENOSINE TRIPHOSPHATE HYDROXIDEHAIR CONDITIONING, SKIN CONDITIONING, SKIN PROTECTING, UV ABSORBER

ZINC ASCORBATE HYDROXIDEHAIR CONDITIONING, SKIN CONDITIONING, SKIN PROTECTING, UV ABSORBER

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 UROCANIC ACID appears in the CosIng inventory

The CosIng inventory lists UROCANIC ACID as a cosmetic ingredient and this page links it to 1 annex record. The inventory entry captures names and identifiers, while the annex record shows where the substance is prohibited, restricted or positively listed in EU cosmetics law.

UROCANIC ACID is also tagged with 1 cosmetic function 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

UROCANIC ACID appears in the EU CosIng inventory and has linked annex records. Check the annex records above for applicable restrictions, concentration limits and conditions of use. Annex II listing means prohibited; Annex III means restricted; Annexes IV, V and VI mean permitted under specified conditions.

The restriction field for UROCANIC ACID reads: "II/418". This is the restriction note recorded in the CosIng inventory for this ingredient. For authoritative conditions and limits, always refer to the linked annex entries above.

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

UV ABSORBER

CAS 104-98-3 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 UROCANIC ACID

This page combines the CosIng inventory entry for UROCANIC ACID with 1 linked Annex II–VI record from the local dataset built from public European Commission cosmetic ingredient materials.

Use this inventory page to research UROCANIC ACID 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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