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Acid Blue 3

CAS 50934-74-2 · 100/100 · High conf.

Also registered as 1 other CAS number

3536-49-0

Acid Blue 3 chemical structure

Concern score

100/100Critical concern based on regulatory listings.
High confidence

Acid Blue 3 in plain language

What it is

On cosmetic ingredient lists it appears as “CI 42051”.

Also known as CI 42051 · CI 42051 /acid blue 3 · Patent blue v · Patent blue v ci 42051 e131 · CI food blue 5 · Patent Blue V (calcium salt)

Show all 35 names

Acidal carmine v · Blue zn 3 · C.I. acid blue 3 · C.I. acid blue 3, calcium salt (2:1) · C.I. food blue 5 · Patent blue 5 · Patent blue v (e 131) · Ariavit patent blue v · Alphazurine 2 G (C.I. 42051) · C.I. 42051 · C.I. 712 · CI (1975) no. 42051 · CI Acid Blue 3 · Cogilor blue 517.11 · Carmine Blue V · Dai-ei acid pure blue vx · E-131 · Ins NO.131 · INS-131 · Merantine Blue V · Mitsui Acid Pure Blue VX · New Patent Blue A-CE Extra · New Patent Blue Extra Pure A · Patent Blue V and L · Schultz No. 826 · Solar Pure Blue VX · Vitasyn patent blue v 50 · Vitasyn patent blue v 85 · patent blue v (e131)

What it does

Used in cosmetics as a colourant and a hair dye. CI 42051 is classed chemically as a triphenylmethane colour.

  • Colorant
  • Hair dyeing
  • Colour
  • Colourant
Is it a concern?
Critical concern: no hazard classifications on record. It is banned in EU cosmetics.

Why it's flagged

Ethanaminium, N-(4-((4-diethylamino)phenyl)(5-hydroxy-2,4-disulfophenyl)methylene)-2,5-cyclohexadien-1-ylidene)-N-ethyl-, hydroxide, inner salt, calcium salt (2:1) (Acid Blue 3; CI 42051) when used as a substance in hair dye products is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.

RestrictedEU EC — banned

The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.

Regulation

Restrictions first, then routine listings from published regulatory sources.

  • EU Annex II — prohibited
  • EU Annex IV — permitted colorant
  • EU permitted colorant
  • EU prohibited in cosmetics

Recorded in these product areas

  • Found in consumer products
  • Beauty
  • Cleaning

  • EUEC

    Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products.

    banned
    View source →
  • EUCosIngActive4 entries
    • CI 42051 is classed chemically as a triphenylmethane colour. It conforms to the formula: Restriction: IV/60 (CI 42051) II/1356 (Acid Blue 3; CI 42051: when used as a substance in hair dye products)Source →
    • Acid Blue 3 is classed chemically as a triphenylmethane colour. It conforms to the formula: Restriction: II/1356 (Acid Blue 3; CI 42051: when used as a substance in hair dye products)Source →
    • Cosmetics Regulation annex IV / ref 60.Source →
    • Cosmetics Regulation annex II / ref 1356.Source →
  • EUECallowed_listedAnnex IV of EU Cosmetics Regulation (EC) 1223/2009: colorants allowed in cosmetic products. Conditions of use and warnings: Purity criteria as set out in Commission Directive 95/45/EC (E 131)
    • Annex IV of EU Cosmetics Regulation (EC) 1223/2009: colorants allowed in cosmetic products. Conditions of use and warnings: Purity criteria as set out in Commission Directive 95/45/EC (E 131)Source →
  • EUEFSAEFSA opinionScientific Opinion on the safety and efficacy of Patent Blue V (E 131) as feed additive for non food-producing animals (EFSA FEEDAP)
    • Scientific Opinion on the safety and efficacy of Patent Blue V (E 131) as feed additive for non food-producing animals (EFSA FEEDAP)Source →
  • GLOBALJECFANO ADI ALLOCATEDJECFA evaluation lists ADI NO ADI ALLOCATED. Functional class: colour.
    • JECFA evaluation lists ADI NO ADI ALLOCATED. Functional class: colour.Source →
  • GLOBALJECFAEvaluatedJECFA evaluation record.
  • USEPAcommercial use observedEPA CPDat observed this chemical in 19 composition records across product categories including Cleaning products and household care, Personal care, Construction and building materials. EPA CPDat classifies this chemical for functional uses including Dye.
    • EPA CPDat observed this chemical in 19 composition records across product categories including Cleaning products and household care, Personal care, Construction and building materials. EPA CPDat classifies this chemical for functional uses including Dye.Source →
  • USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
    • openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

Independent scientific assessments cited by the records we hold, with the year and link where the record gives one.

  • SCCS

    EU Scientific Committee on Consumer Safety

    No SCCS opinion on file.

  • CIR

    Cosmetic Ingredient Review (US expert panel)

    No CIR safety assessment on file.

  • EFSA

    European Food Safety Authority

    • Scientific Opinion on the safety and efficacy of Patent Blue V (E 131) as feed additive for non food-producing animals (EFSA FEEDAP)

      2013 · EU EFSA listing · Read the source →

  • JECFA

    Joint FAO/WHO Expert Committee on Food Additives

    • JECFA evaluation lists ADI NO ADI ALLOCATED. Functional class: colour.

      Year not recorded · GLOBAL JECFA listing · Read the source →

    • JECFA evaluation record.

      Year not recorded · GLOBAL JECFA listing · Read the source →

Evidence & sources

No graded research studies for Acid Blue 3 yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

9 data sources

Where this comes from

  • CosIng

    regulatory · updated 2026-09-23

    Open →

  • EU CosIng Cosmetics Regulation Annexes

    regulatory · updated 2013-05-08

    Open →

  • EFSA OpenFoodTox

    regulatory · updated 2026-10-04

    Open →

  • EPA Chemical and Products Database

    exposure · updated May 2015

    Open →

  • EPA DSSTox Identifiers

    chemistry · updated 2025-12-29

    Open →

  • FDA GSRS UNII

    registry · updated 2026-02-26

    Open →

  • WHO JECFA Database

    regulatory · updated 2026-10-04

    Open →

  • openFDA Substance

    registry · updated 2026-05-24

    Open →

  • PubChem Live Enrichment

    chemistry · updated 2026-05-17

    Open →
Reference links (1)

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Food use

Food-use source coverage is present in the current record.

Good fit

The ingredient appears in food-oriented source coverage or allowed-use references, which makes food use easier to support than a context with no domain signal at all.

Fragrance avoidance

No fragrance-linked caution surfaced in the current profile.

Good fit

This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.

Where it has been recorded

How often EPA CPDat has listed Acid Blue 3 in a product composition. These are source records, not Greenveil catalog products.

Source records

19

Named organisations

6

Cleaning products and household carePersonal careConstruction and building materials

Typical roles

ColorantHair dyeingColourColourant
See products using Acid Blue 3 →

Catalog

Found in these products

Their ingredient lists include Acid Blue 3; each product's own rating depends on its whole formula, so it is shown on the product page, not here.

See all 210 →Find products without it →