What it is
Blue 1 is a triarylmethane synthetic dye that imparts a bright blue color. In sunscreens and other cosmetics it is used at low levels purely for appearance, often to neutralize yellow tones in tone-up or color-correcting products or to give a tinted base. It is highly water-soluble and dosed in very small amounts to achieve the desired shade.
Safety & warnings
Blue 1 is a widely used regulated color additive with a long record of cosmetic use and low irritation potential at the small concentrations employed for tinting. As a non-oil colorant it is not comedogenic and is not a fragrance allergen.
Origin & sourcing
Synthetic; manufactured by organic synthesis as a triarylmethane dye.
Questions everyone asks
Why is Blue 1 added to sunscreen?
It is a cosmetic colorant, typically used in tiny amounts to counteract yellow tones or give a tinted, tone-up appearance to the product.
Is Blue 1 the same as CI 42090?
Yes. Blue 1, Brilliant Blue FCF, and CI 42090 are names for the same synthetic blue dye.