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Vitamin B2

Vitamin ·Strong evidence ·Reviewed May 2026

Essential for energy production, cellular function, and metabolism of fats, drugs, and steroids. Also important for maintaining healthy skin and eyes.

Evidence tier
Strong
Indexed sources
17 1998–2025
Interactions
6
Cost / month
$1.80 budget
Read the sources → Compare profiles
What it's good for
  • Energy production16
  • Migraine prevention3,1
  • Eye health
  • Skin health
What to watch for
  • Bright yellow urine (harmless)
  • Rare GI upset
  • None significant

The bottom line

Evidence rating strong. Most-documented uses: energy production, migraine prevention, eye health. 17 sources indexed (1998–2025), with 6 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Precursor to flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which serve as electron carriers in oxidation-reduction reactions in the electron transport chain and numerous metabolic pathways.16

Class
B Vitamin
Found in food
Eggs, Dairy, Lean meats
Low-status signs
Cracked lips, Sore throat
Absorption
Water-soluble; take with food
Dosing

Dosing & protocol.

Common range
25–400 mg daily (higher for migraines)
Recommended form
Riboflavin-5'-phosphate (active form) or riboflavin

Absorption peaks around 27mg per dose; split larger doses3,6

Dosing protocol

Maintain · 25-50 mg/day with food

Take with food because of bright yellow urine color. Riboflavin-5-phosphate is the active form.6,10

No cycling requiredNo tolerance buildup
Forms

Forms & what to buy.

Ranked by evidence and value.

Riboflavin-5-Phosphate Recommended
Rank 1: coenzymated form. Limited direct form-comparison evidence; ranking is based on review or mechanistic data (PMID: 38201854). Still dephosphorylated before absorption.
Premium10-50 mg/day
Riboflavin
Rank 2: standard economical form. Absorption saturates, so split high doses.
Budget10-400 mg/day
Low-Dose B-Complex Riboflavin
Rank 3: combined B vitamin delivery. Avoids isolated high-dose use.
MidUse label dose
Cost

What it actually costs.

Real-world pricing across three quality tiers. Assumes Riboflavin / Riboflavin-5'-Phosphate.

BudgetBest value
$1.80 /mo
$0.06 per dose
Mid
$4.20 /mo
$0.14 per dose
Premium
$9.60 /mo
$0.32 per dose

Assumes 25-400 mg/day. Vendor basis: NOW/iHerb, Vitacost, Pure Encapsulations, and Amazon marketplace; migraine-level dosing and R-5-P forms cost more. Updated 2026-05-28.

From food

The same dose, as food.

How much you'd eat to match a supplemental dose.

25-400 mg riboflavin
About 2-3 cups milk, 2-3 eggs, 4-6 ounces lean beef, 1 cup almonds, mushrooms, or fortified cereal can cover dietary needs, but migraine-style high doses are not practical from food.

Food can meet normal riboflavin needs; 100-400 mg therapeutic doses require supplements.

Lab work

Markers to track.

What to test, the optimal window inside the conventional range, and how long a response takes.

Erythrocyte Glutathione Reductase Activity Coefficient EGRAC

Riboflavin supplementation lowers EGRAC toward 1.0 as the cofactor (FAD) restores enzyme activity.

Optimal
1–1.2 ratio
Conventional
1–1.4 ratio
Responds in
EGRAC normalizes within 2 to 4 weeks of adequate intake.

Direct plasma riboflavin and urine riboflavin are alternatives but more variable. EGRAC is offered by specialty and research labs.

HomocysteineMMA

Homocysteine Hcy

Vitamin B2 (riboflavin) can modestly lower homocysteine because its active form, FAD, is the cofactor for the MTHFR enzyme that regenerates the folate needed to remethylate homocysteine. The effect appears largest in people carrying the MTHFR 677 TT genotype, whose enzyme is less stable and more dependent on riboflavin, while the average effect across the general population is small and the overall data remain preliminary and somewhat mixed.2,3

Optimal
5–10 umol/L
Conventional
5–15 umol/L
Responds in
If a change occurs, it typically emerges over roughly 8 to 12 weeks of consistent daily intake, since homocysteine shifts slowly and reflects ongoing B-vitamin status rather than a single dose. Recheck no sooner than about 8 weeks.

Draw homocysteine fasting and process the sample promptly, because cells continue releasing homocysteine into serum if a blood tube sits at room temperature, which can falsely raise the result. Timing relative to your riboflavin dose does not matter much for the test itself. Riboflavin works as part of the methylation pathway, so its homocysteine-lowering potential depends on adequate folate, B12, and B6, and it makes sense to ensure those are replete first; in many people folate or B12 drives a larger change than B2 alone. Knowing your MTHFR 677 genotype helps set expectations. Because elevated homocysteine can signal B12 or folate deficiency, kidney issues, or other conditions, and because B12 deficiency in particular can mask or coexist with anemia, share an elevated or persistently abnormal result with a clinician before treating it on your own.

Vitamin B12Folate (serum or RBC)Methylmalonic acid (MMA)
Why people use it

Symptoms it's matched to.

Where this appears in the symptom-to-supplement map, ranked by relevance.

Menstrual (hormonal) migraine

85% relevance

Riboflavin supports mitochondrial energy metabolism in neurons, a pathway implicated in migraine susceptibility, and has reduced migraine frequency in trials.3,6

HormoneModerate evidence400 mg riboflavin once daily as ongoing prophylaxis

Benefit typically takes two to three months to appear, so judge it over a full cycle or more; harmless bright yellow urine is expected.

Dry, cracked lips / angular cheilitis

84% relevance

Riboflavin deficiency is a classic cause of angular cheilitis and cracked lips because it is needed for epithelial cell maintenance, so repletion can resolve deficiency-related cases.2,3

AppearanceModerate evidenceRiboflavin tablets, 5 to 10 mg daily

Most helpful when deficiency is the cause; persistent angular cheilitis may also be fungal or bacterial and should be assessed by a clinician.

Headaches / migraines

75% relevance

Riboflavin supports mitochondrial energy metabolism and is widely used in migraine prevention.16,1

NeurologicModerate evidenceRiboflavin

Classic migraine protocols often use 400 mg/day.

Elevated homocysteine

66% relevance

Riboflavin (as FAD) is the cofactor for MTHFR, and supplementation may lower homocysteine particularly in people with the MTHFR 677TT genotype.2,3

CardiometabolicModerate evidenceRiboflavin (riboflavin-5-phosphate)

Effect is most pronounced in riboflavin-deficient individuals who are homozygous for the MTHFR 677TT polymorphism.

Light sensitivity (photophobia)

66% relevance

Riboflavin at higher doses is an established migraine-prevention nutrient, so it can indirectly ease the photophobia that accompanies migraine.2,3

SensoryModerate evidenceRiboflavin (vitamin B2), 400 mg daily

Takes several weeks to show effect and harmlessly turns urine bright yellow. Best for migraine-driven light sensitivity.

Seborrheic dermatitis (greasy facial scaling and redness)

46% relevance

Riboflavin deficiency can produce a seborrheic-type dermatitis around the nose and mouth, so repletion addresses that specific deficiency picture.

AppearanceInsufficient evidenceRiboflavin tablet (often within a B-complex)

Only relevant if intake is poor (e.g., very limited diet); most seborrheic dermatitis is not riboflavin-driven.

Meniere disease adjunctive support

40% relevance

Riboflavin supports mitochondrial energy metabolism and is an established migraine-prophylaxis nutrient, relevant given the frequent overlap of vestibular migraine with Meniere-type symptoms.2,3

SensoryModerate evidenceRiboflavin 200 to 400 mg daily with food

Evidence is for migraine prevention rather than Meniere itself; harmless apart from bright yellow urine, but seek an accurate diagnosis since the two conditions can mimic each other.

Protocols

Featured in protocols.

Evidence-based stacks that include it, with the exact dose and timing each one uses.

Migraine Prevention Protocol

NeurologicalCoreModerate evidenceIntermediate$25-45/mo
Dose here
400 mg
Timing
Morning with food

Riboflavin (Vitamin B2) is a precursor to the flavin cofactors FAD and FMN that are required for mitochondrial electron transport, and high-dose supplementation may help support the brain energy metabolism that appears impaired in migraine. Harmless bright yellow urine is expected.2,3

Genetics

Who responds differently.

MTHFRC677T~10% of population

Riboflavin is the FAD precursor for MTHFR, and evidence links riboflavin status with blood pressure effects in people with the MTHFR 677TT genotype (PMID 27170501).

Recommendation: Known MTHFR 677TT status may justify checking riboflavin intake when homocysteine or blood pressure concerns coexist.

Safety

Full safety detail.

Side effects

  • Bright yellow urine (harmless)
  • Rare GI upset

Contraindications

  • None significant
Interactions

Interaction records.

InfoSynergy

Vitamin B6

Riboflavin (B2) is needed for the conversion of B6 to its active coenzyme form PLP.

Recommendation: Take as part of a B-complex for mutual support.

InfoSynergy

Vitamin B3

B2 (riboflavin) is needed for the synthesis of NAD+ from niacin (B3) via the kynurenine pathway.

Recommendation: Taking B-complex ensures adequate co-factor support for all B vitamin interconversions.

InfoSynergy

Iron

Riboflavin supports mobilization of stored iron and red blood cell production, so correcting riboflavin status can improve the hematologic response to iron supplementation in deficiency.

Recommendation: Ensure adequate riboflavin intake when treating iron-deficiency anemia, since riboflavin deficiency can blunt the rise in hemoglobin despite iron therapy.

InfoSynergy

Coenzyme Q10

Riboflavin and coenzyme Q10 both support mitochondrial energy production and are used together for migraine prophylaxis, where their effects on the electron transport chain are complementary.

Recommendation: Reasonable to combine for migraine prevention or mitochondrial support. Common research dosing is riboflavin 400mg daily with CoQ10 around 100mg to 300mg daily.

InfoSynergy

Methylfolate

Riboflavin is the cofactor for the MTHFR enzyme that converts folate to its active form, so good riboflavin status improves folate-mediated lowering of homocysteine, especially in people with the MTHFR 677 TT genotype.

Recommendation: Ensure adequate riboflavin when using methylfolate to lower homocysteine, particularly for MTHFR 677 TT individuals in whom riboflavin status strongly modulates the response.

InfoSynergy

Combined Oral Contraceptive

Combined oral contraceptives modestly lower riboflavin (B2) status by altering hepatic enzyme turnover and erythrocyte glutathione reductase activity. The effect is small in well-nourished women but can be relevant for those with limited dietary intake.

Recommendation: A daily multivitamin or B-complex supplement providing 1.3-2 mg of riboflavin is sufficient for women on combined oral contraception. Take with food.

Search all 6 interaction records for Vitamin B2 →

Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Meta-analyses & systematic reviews

7

Randomized controlled trials

3

Reviews & position papers

7
Keep exploring

Deep dives & adjacent profiles.

Vitamin EVitaminVitamin CVitaminVitamin B7VitaminVitamin B5VitaminVitamin B3VitaminVitamin B12Vitamin

This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.

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