Supplement analysis backed by scientific evidence · PT

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Moderate evidenceVitamins & minerals

Riboflavin-5-Phosphate

The phosphorylated "active" form of vitamin B2. High-dose riboflavin has a real but modest preventive effect on migraine; no trial has shown that this form works better than plain riboflavin, and most products contain far less than the studied dose.

Evidence last reviewed: August 2026

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What the science says

  • Migraine prophylaxis Moderate evidence

    A systematic review and meta-analysis of 9 studies (8 randomized trials, 673 subjects) found vitamin B2 at 400 mg/day for three months significantly reduced migraine days, duration, frequency and pain scores, though heterogeneity between trials was high.

  • The effect is small Moderate evidence

    A 2025 dose-response meta-analysis of 22 supplement trials put riboflavin's effect at about 1.3 fewer attacks per month — smaller than magnesium or CoQ10 in the same analysis, and with no significant effect on the other migraine outcomes measured in adults.

  • The active form is not proven better Limited evidence

    Every positive migraine trial used plain riboflavin at 400 mg/day. No randomized comparison of riboflavin-5-phosphate against riboflavin exists for any outcome, and typical R5P products supply 25–100 mg.

Dosage & safety

Studied dose400 mg/day of riboflavin for at least three months in the migraine trials. Riboflavin-5-phosphate products usually give 25–100 mg, well under the studied dose; nutritional needs are only ~1.1–1.3 mg/day.
SafetyAmong the safest supplements; excess is excreted and turns urine bright yellow. Occasional nausea or diarrhoea at gram doses. Judge migraine benefit only after three full months. Not a substitute for medical assessment of new or changing headaches.

Scientific references

Where to buy

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