What are the ingredients in yellow 6 dye?

December 10, 2025 •

2 min read

According to the Environmental Working Group (EWG), Yellow 6 is a synthetic dye derived from petroleum that gives many processed foods and drinks their characteristic yellow-orange hue. Understanding what are the ingredients in yellow 6 dye reveals it is primarily a chemical compound known as Sunset Yellow FCF.

Quick Summary

An in-depth look at the primary chemical compound, manufacturing process, and key constituents of Yellow 6 dye, also known as Sunset Yellow FCF. The article examines its core azo structure, production from petroleum precursors, and includes a discussion of its common forms and safety considerations based on regulatory data.

Key Points

Primary Ingredient: The main component of Yellow 6 dye is the synthetic azo compound known as Sunset Yellow FCF.
Chemical Formula: The chemical name for the key ingredient is disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate, with the formula C16H10N2Na2O7S2.
Origin and Production: Yellow 6 is a synthetic, petroleum-derived dye created through a chemical process involving diazotization and coupling of sulfonic acids.
Trace Contaminants: Some batches of Yellow 6 may contain trace amounts of benzidine, a carcinogenic chemical, which is regulated by safety agencies.
Alternative Names: The dye is also known by other names, including Orange Yellow S, CI 15985, and E110 in the European Union.
Regulatory Status: Yellow 6 is approved for use in food, drugs, and cosmetics by the U.S. FDA, but is sometimes labeled with a warning in Europe due to potential links with hyperactivity in children.

The Chemical Identity: Sunset Yellow FCF

Yellow 6 is a synthetic substance officially named Sunset Yellow FCF. Its chemical name is disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate, classifying it as an azo dye due to its –N=N– group connecting two aromatic rings.

This dye is synthesized from petroleum precursors. The process involves diazotizing 4-aminobenzenesulfonic acid with sodium nitrite in acid, then coupling this with 6-hydroxy-2-naphthalenesulfonic acid. The final product is a sodium salt isolated and dried into a powder.

Principal and Subsidiary Components

Commercial Yellow 6 has a minimum purity, often over 87% required by regulators like the FDA. The remaining content includes minor coloring compounds formed during synthesis, and uncolored salts like sodium chloride or sodium sulfate, which are residues from processing. An insoluble aluminum lake form is also produced for specific uses.

The Controversial Benzidine Contaminant

Trace amounts of benzidine, a known carcinogen, can be found in Yellow 6 and other azo dyes. While these levels are regulated and typically low, concerns exist regarding potential long-term health effects.

Forms and Applications of Yellow 6

Yellow 6 is available as a water-soluble powder and an insoluble aluminum lake, each suited for different applications.


Feature	Water-Soluble Powder	Aluminum Lake
Physical State	Free-flowing powder or granules	Insoluble pigment
Appearance	Reddish-orange to red powder	Varies based on the specific salt used
Solubility	Highly soluble in water	Insoluble in water
Primary Use	Beverages, baked goods, cereals, desserts	Cosmetic coatings, dry mixes, compressed tablets
Regulatory Notes	Subject to batch certification in the US	Permitted in the EU and US for specific uses

Alternatives and Regulation

Natural colorants such as curcumin, annatto, beta-carotene, and saffron can be used as alternatives to achieve yellow and orange colors. Regulatory approaches vary globally; the FDA allows Yellow 6 in food, drugs, and cosmetics, while the EU uses the designation E110 and mandates a warning label about potential hyperactivity in children.

Conclusion

The primary ingredient in Yellow 6 dye is Sunset Yellow FCF, a synthetic azo compound derived from petroleum through a specific chemical manufacturing process. While primarily composed of this colorant, it also contains minor colorants and processing residues. Concerns about contaminants like benzidine have led to increased interest in natural alternatives like turmeric and annatto.

For more information on azo dyes, the National Center for Biotechnology Information's PubChem database is an authoritative source on chemical compounds like Sunset Yellow FCF.

Frequently Asked Questions

No, Yellow 6 (Sunset Yellow FCF) is a synthetic dye that is derived from petroleum and is not naturally occurring.

The primary chemical compound in Yellow 6 is disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate, which is a type of azo dye.

The water-soluble powder is used for products like beverages, while the aluminum lake is an insoluble form used for things like coatings and dry mixes.

Yellow 6 can be contaminated with trace amounts of benzidine, a known carcinogen, although these levels are regulated and considered low by most agencies.

Natural alternatives that provide yellow or orange coloring include curcumin from turmeric, annatto, saffron, and beta-carotene.

Studies have suggested a link between some synthetic food colors, including Yellow 6, and increased hyperactivity in certain sensitive children, leading to warning labels in regions like the European Union.

Yellow 6 is approved for use in many countries, including the United States, but some nations, including Norway, Finland, and Sweden, have banned or restricted its use.