Brilliant blue FCF Lake is the pigment version of the synthetic organic dye FDC compound used primarily as a blue dispersable colorant for processed foods, medications, dietary supplements, and cosmetics. It is classified as a triarylmethane dye and is known under various names, such as FD&C Blue No. 1 Lake or acid blue 9 Lake. It is denoted by E number E133 and has a color index of 42090. It has the appearance of a blue powder and is dispersible in oils and water based binders, with a maximum absorption at about 628 nanometers. It is one of the oldest FDA-approved color additives and is generally considered nontoxic and safe. As a blue color, brilliant blue FCF Lake is often found in many food, cosmetics, personal care and pharmaceutical products.

Brilliant blue FCF Lake is extensively used as a water tracer agent. Due to its ability to retain color for long periods of time, brilliant blue FCF outperforms other dye tracers. Additionally, brilliant blue FCF has a low toxicity level that is favorable for the environment.
Molecular weight: 792.84
Molecular Formula: C37H34N2Na2O9S3
CAS# 3844-45-9
It is used as a coloring agent. In cosmetics and personal care products, it is used in the formulation of a wide variety of product types, eye makeup, makeup, lipsticks, nail polishes, personal cleansers and skin care products.