Ci
CI 42090 (Blue 1)
CI 42090 · Blue 1 · Blue 1 Lake
A water-soluble synthetic blue color additive (a triphenylmethane dye) — present to color the formula, not to do anything to the skin.
What it does
CI 42090 is the colorant code for Brilliant Blue FCF, a synthetic triphenylmethane dye approved by the FDA as FD&C Blue No. 1. In a skincare formula it serves one purpose: visual color. The water-soluble dye form colors the liquid phase; the "Lake" variant is the same chromophore bound to an aluminum substrate so it can be dispersed in oil-phase or anhydrous formulas. Either form contributes only color — no documented skin-care effect.
Also known as
blue 1, brilliant blue fcf, fd&c blue no. 1, acid blue 9
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