INCI name

CI 10020

CI 10020 (Acid Green 1)

Colorantreviewed

A synthetic nitroso colorant, listed in Annex IV and linked in EU data to an Annex II entry.

What it is

CI 10020, also known as Acid Green 1 or Naphthol Green B, is a synthetic green colorant: an iron complex of a sulfonated nitroso-naphthol, as a sodium salt. CosIng lists it as a colorant. In the EU it is listed in Annex IV (colorants), with an entry that excludes products applied on mucous membranes, and the EU data also link it to an entry in Annex II (prohibited substances).

Where it is used

Found in a small number of products.

Limits of interpretation

The INCI list shows which ingredients are present, not how much of each. Above 1%, ingredients are listed in descending order of weight; below 1% the order is free.

See the EU regulation section for what the Annex IV and Annex II entries cover and how they apply.

Functions

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; (precursors of oxidative hair colorants shall be deemed colorants). All authorised colorants are substances in the positive list of Annex IV to the Cosmetics Regulation 1223/2009.

EU regulation

EU · Annex IV, entry 2Trisodium tris[5,6-dihydro-5-(hydroxyimino)-6-oxonaphthalene-2-sulphonato(2-)-N5,O6]ferrate(3-)
Maximum concentration
Not to be used in products applied on mucous membranes
As of
3 November 2026 · (EC) 2009/1223
EU · Annex II, entry 1342Trisodium tris[5,6-dihydro-5-(hydroxyimino)-6-oxonaphthalene-2-sulphonate(2-)-N5,O6]ferrate(3-); (Acid Green 1; CI 10020) when used as a substance in hair dye products
As of
3 November 2026 · (EC) 2013/344

Products with this ingredient (3)

Check a full ingredient list