ACID RED 51
ACID RED 51 must not be used as a substance in hair dye products in the EU — Annex II, entry 1337 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
Disodium 2-(2,4,5,7-tetraiodo-6-oxido-3-oxoxanthen-9-yl)benzoate (CI 45430)
EU regulatory status
Annex of Regulation (EC) No 1223/2009: II/1337
Regulatory note: (when used as a substance in hair dye products)
What entry II/1337 of the Regulation says
2',4',5',7'-Tetraiodofluorescein, its disodium salt (Acid Red 51; CI 45430) and its aluminium salt (Pigment Red 172 Aluminium lake) 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 RED 51 safe in cosmetics?
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In which annex of Regulation 1223/2009 does ACID RED 51 fall?
ACID RED 51 falls under reference II/1337 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 RED 51 perform in cosmetics?
According to the European Commission's CosIng database, ACID RED 51 performs the following functions in cosmetics: COLORANT, 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 RED 51?
Our copy of the EU Safety Gate database currently contains no alerts linking ACID RED 51 to a cosmetic recall. The database is refreshed regularly from the European Commission's official Safety Gate system.