E101II - Riboflavin-5′-phosphate

At a glance

• What it is: a phosphate form of vitamin B2 used as a yellow food color
• E-number: E101II (often the sodium salt)
• Taste/appearance: bright yellow to orange-yellow, clean taste
• Why used: dissolves well in water, colors evenly, can also fortify with B2
• Typical foods: drinks, dairy beverages, desserts, sauces, baked goods
• Label names: “Riboflavin-5′-phosphate,” “riboflavin phosphate (sodium),” “vitamin B2,” or “E101(ii)”

Why is Riboflavin-5′-phosphate added to food?

It gives foods and drinks a bright yellow hue and dissolves easily in water, so it works well in clear beverages and syrups.¹ As a form of vitamin B2, it can also be used to add or restore riboflavin in fortified products.²

What foods contain Riboflavin-5′-phosphate?

You may find it in:

• Sport and energy drinks, flavored waters, and vitamin shots
• Dairy drinks, yogurt drinks, and custards
• Instant desserts, puddings, gel desserts, and sauces
• Baked goods, breakfast cereals, and snack coatings

On labels, look for “Riboflavin-5′-phosphate,” “riboflavin phosphate sodium,” “vitamin B2,” or “E101(ii).”

What can replace Riboflavin-5′-phosphate?

If a different yellow/orange color is needed, common alternatives include:

• curcumin from turmeric
• carotene (beta‑carotene)
• annatto
• Synthetic lemon yellow such as tartrazine

The best choice depends on desired shade, clarity, solubility, flavor impact, and label goals.

How is Riboflavin-5′-phosphate made?

Manufacturers start from riboflavin (vitamin B2) and convert it into the 5′‑phosphate form. Food‑grade material is commonly isolated as the sodium salt, which is freely soluble in water. Its identity and purity specifications are laid down in EU law for food additives (E 101(ii)).¹

Is Riboflavin-5′-phosphate safe to eat?

Riboflavin and its phosphate form are permitted food color additives in the United States (exempt from batch certification) when used according to regulations.³ As a vitamin, riboflavin has very low toxicity, and the U.S. National Institutes of Health reports no tolerable upper intake level (UL) has been set for riboflavin due to a lack of adverse effects in healthy people.²

Does Riboflavin-5′-phosphate have any benefits?

Yes. It supplies vitamin B2, which helps the body convert food into energy and supports normal cellular function, vision, and skin health.² In fortified foods and drinks, this additive can contribute to daily riboflavin intake.²

Who should avoid Riboflavin-5′-phosphate?

• People with a diagnosed sensitivity or allergy to riboflavin (rare) should avoid it.
• Anyone under medical advice to limit vitamin intake should follow their clinician’s guidance. Note: Bright yellow urine after consuming riboflavin is common and harmless.²

Myths & facts

• Myth: It’s an “artificial dye.” Fact: It is a form of vitamin B2 that’s authorized as a food color.
• Myth: It only colors food. Fact: It can also add vitamin B2 when used for fortification.
• Myth: It’s unsafe in drinks. Fact: It is a permitted color additive in the U.S. and widely used when following regulations.³

Riboflavin-5′-phosphate in branded foods

How to spot it on labels:

• Names: “Riboflavin-5′-phosphate,” “riboflavin phosphate (sodium),” “vitamin B2,” or “E101(ii)”
• Common places: multivitamin beverages, energy and sports drinks, flavored dairy, puddings, cereals, and bakery mixes Related entries you might see nearby on an ingredient list include riboflavin (E101) and other yellow colors like curcumin and carotene.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩²

2. Riboflavin — Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional/ ↩ ↩² ↩³ ↩⁴ ↩⁵

3. Color Additives Listed for Use in Food (21 CFR Part 73, Subpart A) — U.S. FDA/eCFR. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-73/subpart-A ↩ ↩²