Ingredient dictionary

Blue 1

Also listed as: FD&C Blue No. 1, Brilliant Blue FCF, CI 42090

Blue 1 is a synthetic blue dye, also called FD&C Blue No. 1, that gives a product its blue color. It is on the label of 79 products in our library. Checked against our library November 6, 2026.

What Blue 1 does

Gives the product a clear blue color
Keeps the shade consistent between batches
Dissolves evenly in water-based formulas

Blue 1 is a synthetic dye made from petroleum-based chemicals. It is a certified color for US food, drug and cosmetic use, which is what the FD&C in its name stands for. Formulators choose it because it gives a bright, clear blue that is easy to match from batch to batch.

In shampoo, a small amount of blue dye shows a clear shade in the bottle. Because it dissolves in water, it blends into the formula without leaving specks. It does not change how the shampoo lathers or rinses, so the color is mostly a visual choice.

Good for

Best for products where a blue shade is wanted; it adds color only and does not change how a formula cleanses or conditions.

Frequently asked questions

Is Blue 1 safe in shampoo?

Blue 1 is a certified color additive, and it is generally well tolerated in cosmetics. Like any dye, it can bother a few people with sensitive skin, so patch testing a new product first is a sensible step.

Does Blue 1 make hair blue?

No. Shampoo is rinsed out with water, and Blue 1 is there to color the product itself, not to tint hair. Its job ends when the product washes away.