Riboflavin

E number E101CAS 83-88-5

Riboflavin is vitamin B2, a yellow-orange compound used both as a nutrient and as a colour. It appears in dairy products, desserts, cereals and drinks, and is what makes some vitamin preparations bright yellow.

Where it is and isn’t permitted

Status of Riboflavin by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1695and 1 further provisionretrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

What it is made from

Produced commercially by fermentation with bacteria or fungi, and formerly by chemical synthesis. It also occurs naturally in milk, eggs and liver, but the additive is not extracted from those.

  • Vegan
  • Vegetarian
CAS registry number
83-88-5
InChIKey
AUNGANRZJHBGPY-SCRDCRAPSA-N
PubChem
CID 493570

Every name it appears under

62 recorded names. A label may use any of them.

E number

  • E101

CAS registry number

  • 83-88-5

As it appears in regulation

  • Riboflavin

Other names

  • (-)-riboflavin
  • 2vxa
  • 6,7-Dimethyl-9-D-ribitylisoalloxazine
  • 7,8-Dimethyl-10-(D-ribo-2,3,4,5-tetrahydroxypentyl)isoalloxazine
  • 7,8-Dimethyl-10-ribitylisoalloxazine
  • Aqua-Flave
  • Beflavin
  • Beflavine
  • Bisulase
  • C.I. Food Yellow 15
  • Dermadram
  • E 101(i)
  • E-101(iii)
  • Fiboflavin
  • Flavaxin
  • Flavin BB
  • Flaxain
  • Freeda
  • HYRE
  • INS NO. 101(I)
  • Ins no.101(iii)
  • Ins-101(iii)
  • Isoalloxazine, 7,8-dimethyl-10-(D-ribo-2,3,4,5-tetrahydroxypentyl)-
  • Isoalloxazine, 7,8-dimethyl-10-D-ribityl-
  • Lacto-flavin
  • Lactobene
  • Lactoflavin
  • Lactoflavine
  • PureVita Vitamin B2
  • Ribipca
  • Ribocrisina
  • Riboderm
  • Riboflavin
  • Riboflavin (Vitamin B2)
  • Riboflavina
  • Riboflavine
  • Riboflavinequinone
  • Riboflavinum
  • Ribosyn
  • Ribotone
  • Ribovel
  • Russupteridine Yellow III
  • Vitaflavine
  • Vitamin B 2
  • Vitamin B-2
  • Vitamin B2
  • Vitamin b2 (as riboflavin)
  • Vitamin Bi
  • Vitamin G
  • vitamin-b2
  • vitaminum b2
  • Vitasan B2

Systematic names

  • 1-Deoxy-1-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)-D-ribitol
  • 7,8-dimethyl-10-((2R,3R,4S)-2,3,4,5-tetrahydroxypentyl)benzo(g)pteridine-2,4-dione
  • 7,8-dimethyl-10-((2S,3S,4R)-2,3,4,5-tetrahydroxypentyl)benzo[g]pteridine-2,4(3H,10H)-dione
  • 7,8-dimethyl-10-(D-ribo-2,3,4,5-tetrahydroxypentyl)benzo(g)pteridine-2,4(3H,10H)-dione
  • 7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5-tetrahydroxypentyl]-2H,3H,4H,10H-benzo[g]pteridine-2,4-dione
  • 7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5-tetrahydroxypentyl]benzo[g]pteridine-2,4-dione
  • Benzo(g)pteridine-2,4(3H,10H)-dione, 7,8-dimethyl-10-(D-ribo-2,3,4,5-tetrahydroxypentyl)-

Hazard reference values

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADI0.5 mg/kg bw/dayconsumersEFSA ANS2013

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/riboflavin.json