ACID BLUE 3
ACID BLUE 3 must not be used as a substance in hair dye products in the EU — Annex II, entry 1356 of Regulation (EC) No 1223/2009. The prohibition is limited to that use; the entry is quoted in full below.
Regulatory data checked on 2026-09-05. The legal status follows Regulation (EC) No 1223/2009 and its annexes; the substance is identified from the European Commission's CosIng database.
About the ingredient
Bis[hydrogen [4-[4-(diethylamino)-5'-hydroxy-2',4'-disulphonatobenzhydrylidene]cyclohexa-2,5-dien-1-ylidene]diethylammonium], calcium salt (CI 42051)
EU regulatory status
Annex of Regulation (EC) No 1223/2009: II/1356
Regulatory note: (Acid Blue 3; CI 42051: when used as a substance in hair dye products)
What entry II/1356 of the Regulation says
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
Source: the European Commission's official CosIng database and Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products. How we assess ingredients — full methodology.
- View the entry in the CosIng database (European Commission)
- Open Regulation 1223/2009 in EUR-Lex
- Check the chemical profile in PubChem
Last updated:
Functions in cosmetics
Frequently asked questions
Is ACID BLUE 3 safe in cosmetics?
ingredientPage.faq.safetyAnswer.bannedConditional
In which annex of Regulation 1223/2009 does ACID BLUE 3 fall?
ACID BLUE 3 falls under reference II/1356 in the annexes of Regulation (EC) No 1223/2009 on cosmetic products. An annex entry may name a substance directly or cover it as part of a broader category. The first part (Roman numeral) indicates the annex: II – prohibited substances, III – substances restricted by conditions, IV – permitted colorants, V – permitted preservatives, VI – permitted UV filters.
What functions does ACID BLUE 3 perform in cosmetics?
According to the European Commission's CosIng database, ACID BLUE 3 performs the following functions in cosmetics: HAIR DYEING. Functions are defined in the CosIng glossary and describe the technological role of a substance in the finished product.
Are there Safety Gate alerts concerning ACID BLUE 3?
Our copy of the EU Safety Gate database currently contains no alerts linking ACID BLUE 3 to a cosmetic recall. The database is refreshed regularly from the European Commission's official Safety Gate system.