Scarlet GN
A synthetic red azo dye once used in foods and now mainly in cosmetics
No single value: Scarlet GN is a material, and its colour varies. The background shows its family, red.
Scarlet GN is a bright red azo dye, also called Food Red 2 or FD&C Red No. 4. It was once used to colour foods but is now mainly found in cosmetics, as its use in food has been banned in many countries due to health concerns.
- Scarlet GN is a synthetic red azo dye
- It was once used as a food colourant (E125)
- Now mainly used in cosmetics like shampoos and soaps
- Banned in food in the US, EU, and Japan
- Made by azo coupling from specific chemical ingredients
What colour is Scarlet GN?
Scarlet GN is a synthetic red dye that gives a strong, bright red colour. It is part of the azo dye group, which means its colour comes from a chemical structure with nitrogen-nitrogen double bonds. Unlike natural reds, Scarlet GN is made in a laboratory and is not found in nature. It is most often used as a disodium salt, which helps it dissolve in water-based products.
Where does Scarlet GN come from?
The name Scarlet GN comes from its vivid red colour, with 'GN' being part of its trade name. It is also known by several standard codes, such as Food Red 2, FD&C Red No. 4, and E125. The dye was first developed for use in foods and cosmetics, but over time, concerns about its safety led to bans on its use in foods in many countries.
How is Scarlet GN made?
Scarlet GN is made by a process called azo coupling. First, 2,4-dimethylaniline-6-sulfonic acid is treated with sodium nitrite and hydrochloric acid to form a diazonium salt. This salt is then reacted with 5-hydroxynaphthalene-1-sulfonic acid, creating the red azo dye. The final product is usually used as a disodium salt to help it dissolve in water.
Where Scarlet GN is used
Scarlet GN was once used to colour foods, but is now mainly found in cosmetics such as shampoos, bubble baths, and liquid soaps. It is approved for cosmetic use in the European Union, South Africa, Turkey, and Thailand. In the United States and Japan, it is banned from use in food, pharmaceuticals, and cosmetics, though it was once allowed in maraschino cherries in the US before being fully banned.
Red around the world
What the red family means from country to country.
The torii gates of Shinto shrines are often painted vermilion, a bright orange-red. The colour is held to keep evil away, and the long tunnels of gates at Fushimi Inari are the best known.
Sacred and holyProtection and healingAweSource: ToriiIn the street protests of the late 2000s, supporters of the ousted prime minister Thaksin Shinawatra wore red shirts, and their royalist opponents wore yellow.
Politics and protestAngerSource: United Front for Democracy Against DictatorshipThe flag is red with a white crescent and star, and is called al bayrak, the red flag. It comes down from the late Ottoman flag.
Politics and protestPrideSource: Flag of TurkeyTurkey red was a bright, fast red for cotton, made from madder root by a long process worked out around Edirne. European dyers spent much of the 1700s trying to copy it.
Nature and renewalSource: Turkey redSince the television maps of the 2000 election, red has meant the Republican Party and blue the Democrats, giving the phrases red state and blue state. Before then the networks had no fixed scheme.
Politics and protestSource: Red states and blue statesMembers of the Economic Freedom Fighters wear red overalls and red berets, in parliament as well as at rallies, to show that they speak for workers.
Politics and protestAngerSource: Economic Freedom FightersShades and relatives of Scarlet GN
Scarlet GN is sometimes confused with other red dyes, but its chemical structure and regulatory status set it apart. It is one of several azo dyes, a group known for their strong colours and synthetic origins. Its various names and codes reflect its use in different industries and countries.
Questions people ask about Scarlet GN
What colour is Scarlet GN?
Scarlet GN is a bright, strong red dye. It is used to give a vivid red shade to products.
Where does the name Scarlet GN come from?
The name refers to its scarlet (red) colour, and 'GN' is part of its trade or standard naming.
Is Scarlet GN still used in food?
No, Scarlet GN is banned as a food additive in the United States, European Union, and Japan due to health concerns.
What is Scarlet GN used for today?
It is mainly used as a colourant in cosmetics such as shampoos, bubble baths, and soaps in some countries.
How is Scarlet GN made?
It is made by reacting 2,4-dimethylaniline-6-sulfonic acid with sodium nitrite and hydrochloric acid, then coupling with 5-hydroxynaphthalene-1-sulfonic acid.
Good reading and sources
The facts on this page come from the Wikipedia article "Scarlet GN", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). Rang rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes. The swatch is an approximation: named colours are not fixed standards, and every screen shows them a little differently. If something is wrong, tell us. Last refreshed 2026-10-03.
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