FD&C Blue 2

What is FD&C Blue 2?

FD&C Blue 2, chemically known as disodium 5,5'-indigotin disulfonate, is a synthetic indigoid colorant produced via industrial oxidation of indigo precursors. This water-soluble dye falls under certified color additives approved for cosmetics. It functions by dispersing evenly in aqueous formulations, delivering a stable bright blue shade that withstands light exposure and pH variations. Commonly found in shampoos, conditioners, eyeliners, lip products, and hair colorants, it ensures consistent pigmentation across production batches and during application. Its high purity standards minimize impurities, allowing use in rinse-off and leave-on items, including sensitive areas like eyes. The dye's solubility enables precise tinting without clumping, supporting formulation stability and aesthetic enhancement in diverse beauty items.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 3 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Colorant
Provides or corrects color using dyes or pigments, helping achieve a consistent shade and visual appearance across batches and throughout wear.
Hair dyeing
Supports chemical color change of hair (e.g., oxidative dye development or bleaching), enabling shade transformation through controlled reactions on the fiber.
Hair colorant
Delivers hair color through dyes and/or pigments (direct or oxidative systems), producing a visible shade change and supporting coverage and longevity.

Benefits

Delivers consistent blue coloring for appealing product visuals.

Maintains shade stability throughout use and storage.

Facilitates uniform application in hair and skin products.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
People desiring vibrant blue shades in makeup or hair care.
Those with dye sensitivities or allergies.
Users of rinse-off products seeking non-comedogenic colorants.
People prone to contact dermatitis from colorants.
Individuals tolerant to certified cosmetic dyes.
Users experiencing irritation from synthetic dyes.

Safety Notes

  • Certified safe for cosmetic use by FDA with purity requirements.
  • EWG rates it moderate due to limited data on long-term effects.

Frequently Asked Questions about FD&C Blue 2

What is FD&C Blue 2?

A water-soluble synthetic dye used to add blue color to cosmetics and hair products.

Is FD&C Blue 2 safe for skin?

Approved for cosmetics by regulators; low irritation potential but test for personal sensitivity.

What products contain FD&C Blue 2?

Shampoos, hair dyes, eyeliners, and lip colors for blue tinting.