Science
Mechanism of Action
It primarily functions as a colorant, imparting a brilliant blue through its triarylmethane structure. Additionally, it can absorb UV radiation (290–400 nm), potentially offering auxiliary photoprotection or stabilizing light-sensitive ingredients.
Research
Clinical Evidence
Low confidence0.5%
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Highly stable in aqueous solutions, though color intensity can subtly shift with extreme pH. It is susceptible to bleaching by strong oxidizing or reducing agents.
Conflicts
- Strong oxidizing agents
- Reducing agents
- Cationic surfactants
Safety
Safety Profile
Permitted as CI 42090 in all cosmetic categories by the EU, with a specific restriction of 0.5% in non-oxidative hair dyes. It is also the certified FD&C Blue No. 1 for food and drug applications.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Primarily serving as an aesthetic colorant, Acid Blue 9 Ammonium Salt is a well-studied ingredient with a low risk profile for cosmetic use.
Related
Similar Ingredients
Finding similar ingredients…
References
Sources