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Vitamin B2 (Riboflavin) Side Effects & Safety

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Bright yellow-orange urine (harmless, due to excess riboflavin excretion)
  • Generally very well tolerated even at high doses (400 mg)
  • Rare: mild diarrhea or increased urination at very high doses
  • Possible increased sensitivity to light at very high doses

Drug & Supplement Interactions

  • Tricyclic antidepressants may reduce riboflavin absorption
  • Probenecid decreases gastrointestinal absorption of riboflavin
  • Doxorubicin may interact with riboflavin metabolism
  • Phenobarbital and other barbiturates increase riboflavin metabolism

Maximum Dose

Do not exceed: No established upper limit — low toxicity due to limited absorption at high doses; excess excreted in urine (causing bright yellow color)

Full Vitamin B2 (Riboflavin) Guide

References

  1. (). Effectiveness of high-dose riboflavin in migraine prophylaxis: a randomized controlled trial. Neurology. DOI
  2. (). Prophylaxis of migraine headaches with riboflavin: a systematic review. Journal of Clinical Pharmacy and Therapeutics. DOI
  3. (). Riboflavin (vitamin B-2) and health. American Journal of Clinical Nutrition. DOI