Last reviewed May 2026 · 1 min read

Is Riboflavin (E101) vegan?

Also known as: Vitamin B2, Lactoflavin, Riboflavine, E101

E-number: E101

Check the Label

Source can be plant or animal.

In short

It depends — Riboflavin can be produced synthetically through microbial fermentation (often vegan) or derived from animal sources like milk, liver, or eggs.

01 · The basics

What is Riboflavin (E101)?

Riboflavin, also known as Vitamin B2, is a nutrient that functions as a yellow-orange food coloring. It is used for both fortification and coloration in a wide range of food products.

02 · The source

Where it comes from

Riboflavin can be produced synthetically through microbial fermentation (often vegan) or derived from animal sources like milk, liver, or eggs. Because the source varies by manufacturer, the label must be checked.

03 · Alternatives

Best vegan alternatives

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Frequently asked

FAQ

Is the Riboflavin in fortified cereals like Kellogg's Corn Flakes vegan?

Often, no. In many fortified cereals, including some from major brands like Kellogg's, the B vitamins (including riboflavin) are derived from lanolin (from sheep's wool) or other animal sources. It's best to seek out cereals with a clear vegan certification.

What is the difference between E101 and E101a?

E101 is the chemical name for riboflavin. E101a refers to riboflavin-5'-phosphate, a more soluble derivative of riboflavin also used in foods. Both can be derived from either vegan or non-vegan sources.

Commonly found in

Fortified cerealsPastaSaucesProcessed cheeseEnergy drinksVitamin supplements