Riboflavin (Vitamin B2)
Summary
Riboflavin is vitamin B2. In adults with migraine, 400 mg/day for 3 months cut attacks and headache days versus placebo, and headache societies rate it probably effective (grade C); trials in children were mixed. In people with the MTHFR 677TT variant, 1.6 mg/day lowered systolic blood pressure (grade C). No upper limit has been set.
Key facts
- A water-soluble B vitamin that forms the coenzymes FMN and FAD[1]
- 1.3 mg/day for men and 1.1 mg/day for women; 1.4 mg in pregnancy and 1.6 mg when breastfeeding[1]
- None set: no adverse effects were reported from intakes as high as 400 mg/day for at least 3 months[1]
- Adult migraine frequency (C); children's migraine (mixed, D); blood pressure in the MTHFR 677TT genotype (C)[2][7][3][4][5][6]
- 400 mg/day for migraine in adults; 50–200 mg/day in children; 1.6 mg/day for blood pressure[2][3][4][5]
- Vegetarian athletes and pregnant or breastfeeding women who rarely eat meat or dairy[1]
- None declared in the trial abstracts; the 2018 pediatric trial was university-funded[7]
- 6 graded human outcomes on this page
- October 10, 2026
How it works
ProposedRiboflavin forms FMN and FAD, coenzymes needed for energy production in mitochondria. Mitochondrial dysfunction is thought to play a part in some migraine, which is the rationale for high doses. For blood pressure, trial authors target people with the MTHFR 677TT variant of a folate enzyme that uses FAD, proposing that riboflavin supports that enzyme.[1][5]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Blood pressure | Grade C | Improved | RCT · n = 91 · 2013 | 2 rows |
| Migraine | Grade C | Improved | RCT · n = 55 · 1998 | 4 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Blood pressure in medicated hypertension with the MTHFR 677TT genotype | Improved | Grade C | RCT · n = 91 · 2013 Adults with hypertension and the MTHFR 677TT genotype, without overt cardiovascular disease Form: Riboflavin · Dose: 1.6 mg/day · Duration: 16 weeks Systolic blood pressure fell 5.6 mm Hg more than with placebo (141.8 to 137.1 vs 143.5 to 144.3 mm Hg); diastolic pressure did not differ. | 23608654 (opens PubMed)Source [5] |
| Migraine attack frequency and headache days | Improved | Grade C | RCT · n = 55 · 1998 Adults with migraine Form: Riboflavin · Dose: 400 mg/day · Duration: 3 months Attack frequency and headache days fell more than with placebo; 59% versus 15% had at least 50% fewer headache days (number needed to treat 2.3). | 9484373 (opens PubMed)Source [2] |
| Blood pressure in cardiovascular patients with the MTHFR 677TT genotype | Improved | Grade C | Crossover RCT · n = 31 · 2012 Patients with premature cardiovascular disease and the TT genotype, 4-year follow-up Form: Riboflavin · Dose: 1.6 mg/day · Duration: 16 weeks Riboflavin lowered systolic blood pressure by 9.2 mm Hg and diastolic by 6.0 mm Hg overall. | 22277556 (opens PubMed)Source [6] |
| Migraine frequency, duration and intensity in children | Mixed | Grade D | RCT · n = 90 · 2018 Children with migraine (Iran) Form: Riboflavin · Dose: Low or high dose (amounts not stated in the abstract) · Duration: 12 weeks The high dose reduced attack frequency and duration versus placebo; the low dose did not, and neither dose changed pain intensity. | 29629048 (opens PubMed)Source [7] |
| Migraine attacks in children | No effect | Grade D | RCT · n = 48 · 2008 Children with migraine Form: Riboflavin · Dose: 200 mg/day · Duration: Not stated in the abstract At least 50% fewer attacks in 12 of 27 children on riboflavin and 14 of 21 on placebo (not significant); no differences on any outcome. | 18984840 (opens PubMed)Source [3] |
| Migraine and tension-type headache frequency in children | Mixed | Grade D | Crossover RCT · n = 42 · 2010 Children aged 6–13 with migraine Form: Riboflavin · Dose: 50 mg/day · Duration: Not stated in the abstract No effect on migraine attack frequency versus placebo; tension-type headache frequency fell more with riboflavin. | 20974610 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Riboflavin | Varies[1][2][5] | Absorbed in the small intestine; absorption is limited, and the small amount absorbed beyond needs is excreted in urine.[1] | Diarrhea and frequent urination reported at 400 mg/day; no toxicity reported from high intakes.[2][1] | Migraine (400 mg/day) and blood pressure (1.6 mg/day) trials |
| Riboflavin 5'-phosphate (FMN) | Varies[1] | No head-to-head absorption data in our sources.[1] | No form-specific tolerance data in our sources.[1] | One of the two active coenzyme forms; sold in some supplements |
Studied doses, daily needs and limits
Doses studied in human trials ranged from 1.6 mg/day for 16 weeks in blood pressure trials to 400 mg/day for 3 months in adult migraine. Pediatric migraine trials used 50–200 mg/day.[5][2][3][4]
Intake reference: Adult RDA: 1.3 mg/day for men and 1.1 mg/day for women (ages 19+); 1.4 mg/day in pregnancy and 1.6 mg/day when breastfeeding. No UL has been set.[1] No UL because no adverse effects have been reported from intakes up to 400 mg/day for at least 3 months; the Food and Nutrition Board still urges caution with excessive amounts. NIH ODS fact sheet (updated May 11, 2022).
Recommended intake and upper limit by age and sex
| Age | Male | Female | Pregnancy | Lactation | Upper limit (UL) |
|---|---|---|---|---|---|
| 0–6 months (AI) | 0.3 mg | 0.3 mg | — | — | Not set |
| 7–12 months (AI) | 0.4 mg | 0.4 mg | — | — | Not set |
| 1–3 years | 0.5 mg | 0.5 mg | — | — | Not set |
| 4–8 years | 0.6 mg | 0.6 mg | — | — | Not set |
| 9–13 years | 0.9 mg | 0.9 mg | — | — | Not set |
| 14–18 years | 1.3 mg | 1 mg | 1.4 mg | 1.6 mg | Not set |
| 19–50 years | 1.3 mg | 1.1 mg | 1.4 mg | 1.6 mg | Not set |
| 51+ years | 1.3 mg | 1.1 mg | — | — | Not set |
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Phototherapy for newborn jaundice or skin disorders
- Lengthy light therapy breaks down riboflavin and can lead to deficiency, so these patients may need monitoring rather than restriction.[1]
- Children with migraine
- Pediatric trials gave mixed results, with high placebo responses, so benefits seen in adults may not carry over.[3][4][7]
- Pregnancy and breastfeeding at high doses
- RDAs rise to 1.4–1.6 mg/day; the 400 mg/day migraine dose was studied in non-pregnant adults only.[1][2]
- Urine color
- The Canadian Headache Society notes discolored urine as a minimal side effect of 400 mg/day.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Safety
No toxicity has been reported, even at high doses.
- High intakes
- Food intakes many times the RDA have no observable toxicity, likely because absorption is limited.[1]
- Migraine trial
- Three minor adverse events: diarrhea and frequent urination with riboflavin, abdominal cramps with placebo.[2]
- Drug interactions
- The NIH fact sheet lists no clinically relevant interactions with medications.[1]
Food sources
| Food | Serving | Amount |
|---|---|---|
| Beef liver, pan fried | 3 ounces | 2.9 mg[1] |
| Breakfast cereal fortified with 100% DV | 1 serving | 1.3 mg[1] |
| Oats, instant, fortified, cooked | 1 cup | 1.1 mg[1] |
| Yogurt, plain, fat free | 1 cup | 0.6 mg[1] |
| Milk, 2% fat | 1 cup | 0.5 mg[1] |
| Almonds, dry roasted | 1 ounce | 0.3 mg[1] |
- Beef liver, pan fried2.9 mg
- Breakfast cereal fortified with 100% DV1.3 mg
- Oats, instant, fortified, cooked1.1 mg
- Yogurt, plain, fat free0.6 mg
- Milk, 2% fat0.5 mg
- Almonds, dry roasted0.3 mg
How to read the label
- Label dose vs clinical doseThe adult RDA is 1.1–1.3 mg/day, the blood pressure trials used 1.6 mg/day, and the migraine trial used 400 mg/day, about 300 times the RDA.[1][5][2]
- Migraine productsSome migraine supplements combine riboflavin with magnesium and coenzyme Q10; the single-ingredient adult trial used riboflavin alone.[2][8]
- Food firstFortified cereals and oats provide about 1.1–1.3 mg per serving, close to the full RDA.[1]
Cost per studied dose, without the sales pitch
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Cost per studied dose
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Frequently asked questions
Does riboflavin help migraines?
In adults, 400 mg/day for 3 months reduced attacks and headache days versus placebo, and headache societies rate it probably effective. Results in children are mixed.[2][1][3][4][7]
How long does riboflavin take to work for migraine?
The adult trial lasted 3 months, and the pediatric trial with a positive high-dose result ran for 12 weeks.[2][7]
Does riboflavin lower blood pressure?
In people with the MTHFR 677TT gene variant, 1.6 mg/day lowered systolic pressure by about 5.6–9.2 mm Hg; it has not been shown in people without the variant.[5][6]
Is high-dose riboflavin safe?
No upper limit has been set because no harm has been reported at doses up to 400 mg/day for 3 months; the most noticeable effect is discolored urine.[1][2]
Do most people get enough riboflavin?
The ODS lists vegetarian athletes and pregnant or breastfeeding women who rarely eat meat or dairy as groups that may run low.[1]
Which foods are high in riboflavin?
Beef liver, fortified cereals and oats, yogurt, milk and almonds.[1]
Sources
- [1]Riboflavin: Fact Sheet for Health Professionals (updated May 11, 2022). NIH Office of Dietary Supplements, 2022. fact-sheet
- [2]Effectiveness of high-dose riboflavin in migraine prophylaxis. A randomized controlled trial.. Neurology, 1998. RCT
- [3]High-dose riboflavin for migraine prophylaxis in children: a double-blind, randomized, placebo-controlled trial.. J Child Neurol, 2008. RCT
- [4]Medium-dose riboflavin as a prophylactic agent in children with migraine: a preliminary placebo-controlled, randomised, double-blind, cross-over trial.. Cephalalgia, 2010. crossover-RCT
- [5]Blood pressure in treated hypertensive individuals with the MTHFR 677TT genotype is responsive to intervention with riboflavin: findings of a targeted randomized trial.. Hypertension, 2013. RCT
- [6]Riboflavin offers a targeted strategy for managing hypertension in patients with the MTHFR 677TT genotype: a 4-y follow-up.. Am J Clin Nutr, 2012. crossover-RCT
- [7]Prophylactic effect of riboflavin on pediatric migraine: a randomized, double-blind, placebo-controlled trial.. Electron Physician, 2018. RCT
- [8]Effects of selected dietary supplements on migraine prophylaxis: A systematic review and dose-response meta-analysis of randomized controlled trials.. Neurol Sci, 2025. meta-analysis
What changed
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Adversarial review pass: every evidence row re-read against its PubMed abstract. Official sources opened before citing: NIH ODS Riboflavin fact sheet for health professionals (updated May 11, 2022), whose RDA, no-UL rationale, food table, migraine guideline summary, groups at risk and interaction statement are transcribed here. Industry ties: none declared; the 2018 pediatric trial was funded by Kashan University of Medical Sciences and the 2025 meta-analysis declares no conflicts; funding for the other trials is not stated in PubMed. Retraction, expression-of-concern, erratum and withdrawn checks on all 7 PMIDs: none flagged. Page set indexable. Independent browser review (4 parallel reviewers, every evidence row checked against its abstract and official sources on the Vercel preview) found: editorial phrase on urine color removed to match the ODS source.