ACID BLUE 9 is graded C (Moderate) by Expert·ING, based on COSING regulatory data. It is restricted under EU COSING — AnnexIII-SAFETY-.
ACID BLUE 9
Safety grade: C
Acid Blue 9 is a synthetic blue dye commonly used to color hair and cosmetic products. It creates vibrant blue shades that bind to hair strands or stay suspended in formulations.
This ingredient is used as a colorant in hair dyes and cosmetics to impart blue color and enhance the visual appearance of the product or the user's hair.
Graded using: COSING.
- EU COSING — Restricted
Last verified: May 26, 2026
Safer alternatives to ACID BLUE 9
- CI 42090 — Grade A. Identical chemical composition; direct blue colorant substitute.
Other Hair Dyeing ingredients
- RESORCINOL — Grade E**
- THYMOL — Grade A
- M-AMINOPHENOL — Grade C**
- P-AMINOPHENOL — Grade C**
- 2-METHYLRESORCINOL — Grade C
- 4-AMINO-2-HYDROXYTOLUENE — Grade C
- P-PHENYLENEDIAMINE — Grade D**
- 2-METHYL-5-HYDROXYETHYLAMINOPHENOL — Grade C