Riboflavin is said to have to some effect in reduction of migraine aura but is 400mg a day really safe option for migraine treatment?

Riboflavin: That is a big dose of riboflavin, but 400 mgs orally of it daily for 3 months was used in a study to prevent migraine and there were no adverse effects but I don't know how effective it was. By injection,however,toxicity could occur. I'm unsure whether your physician or most physicians would be comfortable with a megadose of any supplement,however. Discuss with your physician.

REALLY safe!: Riboflavin has no known toxic dose. It's EXTREMELY SAFE. The only common side effect is very yellow urine that smells like B vitamins. It's FAR safer than every drug used for migraines. It reduces migraines by over 50% in 59% who tried it. See https://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional/ It may work better combined with magnesium taurate, butterbur and other natural remedies.