Vitamin B2 (Riboflavin)
water-soluble
Key Takeaways
- Precursor to coenzymes FMN and FAD, required by 90+ flavoproteins
- Plays roles in citric acid cycle, beta-oxidation, and amino acid metabolism
- Emerging evidence supports use in migraine prophylaxis in adults
- FDA daily value is 1.3 mg
- Required for biosynthesis of CoA, CoQ, heme, and pyridoxal 5-phosphate
Evidence Spectrum
15 studies reviewed →15
Studies Reviewed
1.3 mg
RDA (Adults (FDA Daily Value))
water-soluble
Solubility
Role in the Body
Vitamin B2 (riboflavin) is an essential dietary compound used for the enzymatic biosynthesis of FMN and FAD. The human genome contains 90 genes encoding flavin-dependent proteins (pmid:23500531). The majority catalyze oxidation-reduction reactions in the citric acid cycle, beta-oxidation, and amino acid degradation. Riboflavin also has neuroprotective properties, inhibiting glutamate release from synaptosomes (pmid:34477538).
- Precursor to FMN and FAD coenzymes
- Required for citric acid cycle and beta-oxidation
- Biosynthesis of CoA, CoQ, heme, pyridoxal 5-phosphate
- Neuroprotective via glutamate modulation
Supplement Forms
Riboflavin (free form)
RecommendedBioavailability: 0.6%
Standard supplement; absorption saturates ~27 mg/dose
Riboflavin 5-phosphate (FMN)
RecommendedBioavailability: 0.6%
Active coenzyme form
Food Sources
Dairy products
Eggs
Lean meats
Fortified cereals
Almonds
Mushrooms
Spinach
Deficiency
Prevalence: Uncommon in developed countries due to fortification; concern in dairy-limited diets.
Symptoms:
- Angular cheilitis
- Glossitis
- Seborrheic dermatitis
- Sore throat
- Photophobia
Risk Factors:
- Vegan/dairy-free diets
- Chronic alcoholism
- Elderly with poor intake
Safety & Interactions
Possible Side Effects:
- • Well tolerated; bright yellow urine at high doses (pmid:26780280)
Drug Interactions:
- • Required for B6 activation to pyridoxal 5-phosphate
- • Involved in folate metabolism
Contraindications:
- • No known contraindications
Frequently Asked Questions
What does B2 do?
Precursor to FMN/FAD coenzymes required by 90+ flavoproteins for energy, fat oxidation, and cofactor synthesis.
Can B2 help migraines?
Evidence suggests 200-400 mg/day reduces migraine frequency in adults.
Research Sources
15 peer-reviewed studies analyzed from PubMed. 4 directly cited in this review.