Riboflavin
A yellow-orange vitamin used as a food colour and supplement
No single value: Riboflavin is a material, and its colour varies. The background shows its family, yellow.
Riboflavin is a yellow-orange crystalline powder, also known as vitamin B2. It is found in food, used as a dietary supplement, and added as a colouring agent to foods. Riboflavin is essential for energy metabolism and is widely produced by fermentation using fungi and bacteria.
- Riboflavin is also called vitamin B2
- It is a yellow-orange crystalline powder
- Used as food colouring E101 in Europe
- Produced by fermenting fungi and bacteria
- Excess gives urine a bright yellow tint
What colour is Riboflavin?
Riboflavin is a water-soluble vitamin that appears as a yellow-orange crystalline powder. It is slightly bitter and has a faint smell. In its pure form, it dissolves in water and some other polar liquids, but not in oils or non-polar solvents. Riboflavin stands out for its strong yellow colour, which is so intense that excess amounts in the body can tint urine a bright yellow.
Where does Riboflavin come from?
The name 'riboflavin' comes from its chemical structure, which includes a ribose sugar and a flavin ring. It is also called vitamin B2 and was first made by chemical synthesis before being produced on a large scale by fermenting fungi and bacteria. Animals, including humans, cannot make riboflavin and must get it from food or supplements.
How is Riboflavin made?
Riboflavin is made industrially by fermenting certain fungi and genetically modified bacteria, which naturally produce the vitamin. Earlier methods used chemical synthesis, but fermentation is now preferred for commercial production. In nature, riboflavin is made by bacteria, fungi, and plants, but not by animals.
Where Riboflavin is used
Riboflavin is used as a food colouring, labelled as E101 in Europe. It is added to foods like cereals, bread, and dairy products to boost nutritional value and colour. In medicine, it is taken as a supplement and is used in treatments for certain eye conditions and to help prevent migraines.
Yellow around the world
What the yellow family means from country to country.
The yellow disc of the Aboriginal flag is the sun, giver of life. The flag was designed by the Luritja artist Harold Thomas and first flown in Adelaide in 1971.
Sacred and holySource: Australian Aboriginal flagAt the gaye holud, held a day or two before a wedding, relatives rub turmeric paste on the bride and groom. Guests dress in yellow and orange.
Weddings and marriageFestival and celebrationJoySource: Gaye holudOn Pohela Falgun, the first day of spring, young women wear yellow and orange saris, a shade called basanti, with flowers in their hair.
Festival and celebrationNature and renewalJoySource: Pohela FalgunThe Flemish flag is a black lion on yellow, and the Walloon flag a red cockerel on yellow. The language communities are often shown by these colours.
Politics and protestPrideSource: Flag of FlandersThe flag is yellow, the colour of the Sultan. By custom, ordinary people did not wear yellow in the ruler's presence.
Royalty and powerPrideSource: Flag of BruneiThe national football team plays in a yellow shirt with green trim, the canarinho. It was chosen in a newspaper contest after the 1950 World Cup final was lost in white.
Festival and celebrationPrideJoySource: Brazil national football teamShades and relatives of Riboflavin
Riboflavin-5'-phosphate, also called FMN or E101, is a more water-soluble form of riboflavin used in foods. The pure vitamin is sometimes confused with other yellow food dyes, but its nutritional role and chemical structure set it apart.
Questions people ask about Riboflavin
What colour is riboflavin?
Riboflavin is a yellow-orange crystalline powder. Its strong yellow colour is noticeable even in small amounts and is used to colour foods.
Where does the name riboflavin come from?
The name comes from its chemical structure, which includes a ribose sugar and a flavin ring. It is also known as vitamin B2.
How is riboflavin made?
Most riboflavin is now made by fermenting fungi and genetically modified bacteria. Earlier, it was produced by chemical synthesis.
What is riboflavin used for?
It is used as a food colouring, a dietary supplement, and in medical treatments for certain eye conditions and migraine prevention.
Why does riboflavin turn urine yellow?
Any riboflavin not needed by the body is quickly excreted in urine, giving it a bright yellow colour.
Good reading and sources
- Riboflavin on WikipediaEncyclopedia
- More pictures on Wikimedia CommonsPictures
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Riboflavin", 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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