Acid blue 9 aluminum lake is a synthetic triphenylmethane and aluminium dye.
Triphenylmethane is a hydrocarbon that serves as a base for many synthetic dyes.

Safety
Aluminium can interfere with different biological processes (cellular oxidative stress, calcium metabolism, etc.), so it can induce toxic effects in different organs and systems, and the nervous system is the main target of its toxicity.

What it is used for and where
Cosmetics
Hair dyeing. It is an ingredient that adds a colouring to the hair that can be temporary, semi-permanent or permanent depending on what other ingredients are added to achieve the result. The pH for hair dyeing is generally between 9 and 10.
Synonyms: EC number 272-939-6

CAS: 68921-42-6