Blue 4

What Is It?

Blue 4 (D&C Blue No. 4) is a colorant. In cosmetics and personal care products, Blue 4 is used in the formulation of aftershave lotions, bath products, bubble baths, cleansing products, colognes, personal cleanliness products, shampoos, skin care products and skin fresheners. Blue 4 is subject to certification by the Food and Drug Administration (FDA).

Why Is It Used?

Blue 4 imparts a color to cosmetics and personal care products.

Scientific Facts

Blue 4 is a synthetic pigment sometimes referred to in general terms as a triphenylmethane color. Color additives are classified as straight colors, lakes, and mixtures. Straight colors are color additives that have not been mixed or chemically reacted with any other substance. Blue 4 is a straight color.

Safety Information

The Food and Drug Administration (FDA) reviewed the safety of Blue 4 and determined that it may be safely used for coloring externally applied drugs and cosmetics when it conforms to FDA specifications. It is not permitted for use in products intended for use in the eye area or intended for use on the lips. Cosmetic Ingredient Review (CIR) has deferred evaluation of this ingredient because the safety has been assessed by FDA. This deferral of review is according to the provisions of the CIR Procedures.

All color additives used in foods, drugs and cosmetics in the United States must be approved by FDA and listed in the Code of Federal Regulations. In some cases, FDA requires that each batch of color produced for use in regulated products can be used only if it is certified by the agency to meet strict specifications. FDA maintains a laboratory especially for this purpose and color manufacturers must pay a fee to support this activity. FDA only approves colors after extensive review of all safety data and publication of the basis for its approval in the Federal Register.

You can find out more about FDA regulation of colors at:

Link to FDA Code of Federal Regulations for Blue 4

In the European Union, Blue 4 must be listed on the label as CI 42090. CI 42090 is a coloring agent allowed in all cosmetic products (see Annex IV).

Link to the EU Cosmetic Regulation:…

You can learn more about the regulation and labeling of colors at:…

More Scientific Information

Certifiable color additive such as Blue 4 are used widely because their coloring ability is more intense than most colors derived from natural products; thus, they are often added in smaller quantities. In addition, certifiable color additives are more stable, provide better color uniformity and blend together easily to provide a wide range of hues. Certifiable color additives generally do not impart undesirable odors or flavors while color derived from foods such as beets and cranberries can produce such unintended effects. Certifiable color additives typically are available for use as either “dyes” or “lakes.” Dyes dissolve in water and are manufactured as powders, granules, liquids or other special purpose forms. Lakes are the water insoluble form of the dye. Blue 4 is principally the diammonium salt of ethyl[4-[p[ethyl(m- sulfobenzyl)amino]-[alpha]-(o- sulfophenyl)benzylidene]-2,5-cyclohexadien-1-ylidene] (m- sulfobenzyl) ammonium hydroxide inner salt with smaller amounts of two other salts. In cosmetics and personal care products, Blue 4 functions as a colorant.