What does the restriction note for ACID RED 51 mean?

The restriction field for ACID RED 51 reads: II/1337 (when used as a substance in hair dye products). This is the restriction note from the CosIng inventory. For authoritative conditions and limits, always refer to the linked annex entries.

How do I check if my formula contains ACID RED 51?

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 3162912/08/2020

ACID RED 51

Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate (CI 45430)

ACID RED 51 is linked to 2 EU annex records on this page. Inventory note: II/1337 (when used as a substance in hair dye products).

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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	2	English and EU languages
Great Britain	Source mapped Official source mapped; ingredient rule not imported	0	English
Canada	Source mapped Official source mapped; ingredient rule not imported	0	English and French
New Zealand	Source mapped Official source mapped; ingredient rule not imported	0	English
ASEAN	Source mapped Official source mapped; ingredient rule not imported	0	English and national languages
China	Source mapped Official source mapped; ingredient rule not imported	0	Chinese with selected English material
Japan	Source mapped Official source mapped; ingredient rule not imported	0	Japanese; official English translation available
South Korea	Source mapped Official source mapped; ingredient rule not imported	0	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	Source mapped Official source mapped; ingredient rule not imported	0	Portuguese with INCI crosswalks
India	Source mapped Official source mapped; ingredient rule not imported	0	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 1342-25-2

CAS 1342-25-2PubChem CID 704905

N2-(4-Bromophenyl)-1,3,5-triazine-2,4-diamine

IUPAC name: 2-N-(4-bromophenyl)-1,3,5-triazine-2,4-diamine

Molecular formula: C9H8BrN5
Molecular weight: 266.10 g/mol
Exact mass: 264.99631 Da
XLogP3: 2.2
Topological polar surface area: 76.7 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 5
Covalent units: 1
Defined stereocentres: 0

Also known as

N-(4-Bromo-phenyl)-[1,3,5]triazine-2,4-diaminen-(4-bromophenyl)-1,3,5-triazine-2,4-diamineCCG-274101CS-0284738EN300-06463SR-01000028696SR-01000028696-1(4-amino(1,3,5-triazin-2-yl))(4-bromophenyl)amine

1 more reported name

1,3,5-Triazine-2,4-diamine, N2-(4-bromophenyl)-

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External database identifiers

EPA DTXSID:DTXSID101366094

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

PubChem 2D chemical structure for CAS 16423-68-0

CAS 16423-68-0PubChem CID 3259

Erythrosine

Fd&c red no. 3 is used as a food additive [EAFUS] ("EAFUS: Everything Added to Food in the United States. [http://www.eafus.com/]").<br /> Fd&c red no. 3 belongs to the family of Xanthenes. These are polycyclic aromatic compounds containing a xanthene moiety, which consists of two benzene ring joined to each other by a pyran ring. — Toxin and Toxin Target Database (T3DB)

IUPAC name: 3',6'-dihydroxy-2',4',5',7'-tetraiodospiro[2-benzofuran-3,9'-xanthene]-1-one

Molecular formula: C20H8I4O5
Molecular weight: 835.9 g/mol
Exact mass: 835.6551 Da
XLogP3: 6.0
Topological polar surface area: 76.0 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 5
Covalent units: 1
Defined stereocentres: 0

Also known as

E127FD & C red no. 33',6'-dihydroxy-2',4',5',7'-tetraiodospiro(2-benzofuran-3,9'-xanthene)-1-oneFDC Red No. 3RefChem:591122Spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one, 3',6'-dihydroxy-2',4',5',7'-tetraiodo-, disodium saltErythrosine, sodium anhydrousNSC-36685

16 more reported names

Erythrosin BTetraiodofluoresceinSolvent Red 140IodeosinErythrosine acidErythrosine, phenolic2',4',5',7'-Tetraiodofluorescein2,4,5,7-ErythrosinC.I. Solvent Red 140Spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 3',6'-dihydroxy-2',4',5',7'-tetraiodo-Erythrosine B (free acid)1A878FZQ9BNSC-328781Spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one, 3',6'-dihydroxy-2',4',5',7'-tetraiodo-C.I. Food Red 14FD and C Red No. 3

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External database identifiers

ChEMBL:CHEMBL1332616
EPA DTXSID:DTXSID7044843
PubMed:22485174

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 ACID RED 51

INCI name

ACID RED 51

INN name

erythrosine

Description

Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate (CI 45430)

Record provenance

Inventory reference: 31629
Imported identity: ACID RED 51
Source update: 12/08/2020

European Commission CosIng source notes

Annex records for ACID RED 51

Annex II Restriction reference

Entry 1337

2',4',5',7'-Tetraiodofluorescein, its disodium salt (Acid Red 51; CI 45430) and its aluminium salt …

CAS: 15905-32-5 -- 16423-68-0 -- 12227-78-0

EC: 240-046-0 -- 240-474-8 -- 235-440-4

Annex IV Identified ingredient

Entry 80

CI 45430

CAS: 12227-78-0

EC: 240-474-8

Key data

CAS

16423-68-0; 1342-25-2

240-474-8

Restriction

II/1337 (when used as a substance in hair dye products)

Function

COLORANT: Exclusively or mainly intended to colour the cosmetic product, the body as a whole or certain parts thereof, by absorption or reflection of visible light. All authorised colorants are substances in the positive list of Annex IV to the Cosmetics Regulation 1223/2009.
HAIR DYEING: Imparting color to hair. Hair dyeing preparations may be temporary, semi-permanent, or permanent, depending on the length of time the colorant remains on the hair.

Official EU ingredient-name evidence

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

#870 · ACID RED 51

Ingredients with overlapping formulation functions

ACID BLUE 62COLORANT, HAIR DYEING

ACID RED 14COLORANT

ACID RED 14 ALUMINUM LAKECOLORANT

ACID RED 195COLORANT

ACID RED 87COLORANT, HAIR DYEING

ACID YELLOW 3 ALUMINUM LAKECOLORANT

ACID YELLOW 73COLORANT, HAIR DYEING

ACRYLIC RESIN COATED ALUMINUM POWDERCOLORANT

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 ACID RED 51 appears in the CosIng inventory

The CosIng inventory lists ACID RED 51 as a cosmetic ingredient and this page links it to 2 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.

ACID RED 51 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

ACID RED 51 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 ACID RED 51 reads: "II/1337 (when used as a substance in hair dye products)". 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, ACID RED 51 carries the following function designation(s):

CAS 16423-68-0; 1342-25-2 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.

Use the INCI Checker to screen a full ingredient list across selected markets, or compare this substance across all supported market datasets.

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Source note for ACID RED 51

This page combines the CosIng inventory entry for ACID RED 51 with 2 linked Annex II–VI records from the local dataset built from public European Commission cosmetic ingredient materials.

Use this inventory page to research ACID RED 51 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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