CI 42051, also known as Patent Blue V, is a synthetic blue dye used in cosmetics to give products a blue color. It is a common colorant in various personal care items.

Is CI 42051 safe for all skin types?

While generally considered safe, some individuals with sensitive skin may experience irritation or allergic reactions to CI 42051. Patch testing is recommended if you have known sensitivities to dyes.

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CI 42051

CI 42051 is a synthetic blue triarylmethane dye used to impart a blue color to cosmetic products. It is water-soluble and provides a bright blue shade. This ingredient is solely for aesthetic purposes and does not offer any functional benefits to the skin or hair.

NoneColorantVeganEvidence: Medium

BenefitNone 0 / 4

RiskModerate 1.5 / 4

Sensitization i1.5 / 4

Risk of allergic contact dermatitis or immune-based reactions. Fragrance allergens, preservatives, botanicals, and some dyes may score here.

Irritation i1.5 / 4

Risk of short-term irritation — stinging, burning, dryness, redness, or discomfort. Common for strong actives, acids, retinoids, fragrances, and harsh surfactants.

Rated by SpottyLabs' ingredient methodology, independent of brands.

Things to watch

May cause allergic reactions in sensitive individuals
Potential for skin irritation

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Frequently asked questions

What is CI 42051?: CI 42051, also known as Patent Blue V, is a synthetic blue dye used in cosmetics to give products a blue color. It is a common colorant in various personal care items.
Is CI 42051 safe for all skin types?: While generally considered safe, some individuals with sensitive skin may experience irritation or allergic reactions to CI 42051. Patch testing is recommended if you have known sensitivities to dyes.