RED 504W， Red 4 (CI 14700) is a synthetic colorant commonly used in skincare and makeup products to impart a vibrant red hue with an orange or yellow undertone. It is approved for use in cosmetics by regulatory bodies like the U.S. FDA and the European Union's SCCS.

Additional info:

Red 4 (CI 14700) is a common colorant used in cosmetics to provide a red color. Red 4 is identified chemically as the disodium salt of 3-[(2,4-dimethyl-5-sulfophenyl)azo]-4-hydroxy-1-naphthalenesulfonic acid. Red 4 is soluble in water, while Red 4 Lake is insoluble in water. Red 4 and Red 4 Lake are the abbreviated names given by FDA for the certified color, FD&C Red No. 4. Certifiable color additive such as Red 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 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. Lakes are typically more stable than dyes and are ideal for coloring products lacking sufficient moisture to dissolve dyes.