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Riboflavin (Vitamin B2) (E101) — What You Need to Know

Safe(10/10)Nature-Identical

The score is an eNumbers.org editorial summary, not an official agency rating or medical advice. Start with the regulatory status and primary sources below.

What Is Riboflavin (Vitamin B2)?

Riboflavin is vitamin B2, an essential water-soluble nutrient that also serves as a yellow food coloring. It is produced commercially via fermentation using the fungus Ashbya gossypii, yielding a molecule identical to naturally occurring riboflavin. Excess riboflavin is readily excreted in urine, giving it a characteristic bright yellow color.

What Is It Used For?

Used as both a food coloring and a nutritional fortification agent in cereals, baby food, dairy products, and energy drinks. Its dual function as a vitamin and colorant makes it one of the most benign food additives.

Function: Yellow food coloring and vitamin fortification agent
2 mg
Dataset exposure estimate

Exposure figures are population-level references, not personal limits. Actual intake varies by diet, product and jurisdiction.

Regulatory & Editorial Context

📊
Acceptable Daily Intake (ADI)
Not specified mg/kg bw/day
🏛️
Regulatory Status
🇺🇸 USA (FDA): GRAS (Generally Recognized as Safe)
🇪🇺 EU (EFSA): Authorized (ADI not specified — no safety concern)
⚠️ Key Concerns

Riboflavin is essentially vitamin B2, an essential nutrient required for normal cellular function, growth, and energy metabolism. No safety concerns exist at any realistic dietary intake level. Excess riboflavin is efficiently excreted via the kidneys, which is why it causes bright yellow urine at higher doses. Both natural extraction and biosynthesis via fermentation using Ashbya gossypii are used in commercial production. EFSA considers it so safe that no numerical ADI was deemed necessary.

Editorial context score

eNumbers.org currently assigns Riboflavin (Vitamin B2) an editorial context label of Safe with a score of 10/10. This is 4.2 points above the database average for colorings (5.8/10). Dataset reference year: 2013.

This score is not issued by EFSA, FDA, WHO or another regulator.

Commonly Found In

CerealsBaby foodEnergy drinksPastaNutritional supplementsDairy products
Example brands:
Kellogg'sNestléRed Bull

Always check the label for E101 or 'Riboflavin (Vitamin B2)'

▶Chemical Information
Formula: C17H20N4O6
Molecular Weight: 376.36 g/mol
CAS Number: 83-88-5
INS Number: 101
Also known as: E101, Vitamin B2, Lactoflavin, INS 101

Frequently Asked Questions about Riboflavin (Vitamin B2)

Current dataset status: FDA — GRAS (Generally Recognized as Safe); EFSA/EU — Authorized (ADI not specified — no safety concern). Reported concerns: Riboflavin is essentially vitamin B2, an essential nutrient required for normal cellular function, growth, and energy metabolism. No safety concerns exist at any realistic dietary intake level. Excess riboflavin is efficiently excreted via the kidneys, which is why it causes bright yellow urine at higher doses. Both natural extraction and biosynthesis via fermentation using Ashbya gossypii are used in commercial production. EFSA considers it so safe that no numerical ADI was deemed necessary. Regulatory status and individual risk are not the same; check the primary sources and permitted conditions of use.

Quick Facts

E-Number
E101
INS Number
101
Category
Colorings
Origin
Nature-Identical
FDA Status
GRAS (Generally Recognized as Safe)
EFSA Status
Authorized (ADI not specified — no safety concern)
ADI
Not specified mg/kg bw/day
Dataset Review
2013
Ingredient-level Dietary Notes
Vegan: ✅ YesHalal: ✅ YesKosher: ✅ YesGluten-Free: ✅ Yes

Carriers, processing aids and product certification can change suitability. Verify the final label and certifier.

Quick Links

Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional for health-related decisions.

Related Additives

Other colorings in the same family

Beta-Carotene (E160a)Curcumin (E100)Annatto (E160b)