High daily doses have the strongest evidence for fewer migraine attacks, with expected yellow urine and occasional digestive upset. In people with two copies of a common folate-processing enzyme change, low-milligram doses have lowered a blood waste marker; the blood-pressure claim is very uncertain. Not a general longevity drug. A low-risk lever for those uses or low status. (Full Review)

Protocol

Migraine prophylaxis (Schoenen / American Academy of Neurology Level B)

400 mg once daily

At least 3 months, often with magnesium and coenzyme Q10

MTHFR 677TT protocols (McNulty / Ulster)

1.6 mg daily

12–16 weeks; OptiPREG uses 5 mg in pregnancy

Time of day

Morning with breakfast

Meal timing drives absorption; late high doses have no sleep signal

Time to effect

Migraine

3 months

Horizon before judging nonresponse

Homocysteine

12–16 weeks

Measured in MTHFR 677TT trials

Blood pressure

12–16 weeks

Measured in MTHFR 677TT trials

Benefits

High: Reduction of Migraine Attack Frequency

Medium: Lowering of Homocysteine in MTHFR 677TT Genotype; Blood Pressure Reduction in MTHFR 677TT Genotype

Low: Support of Hemoglobin When Iron Intake Is Limited; Lower Prevalence of Nuclear Cataract; Lower Colorectal Cancer Risk

Speculative: Mitochondrial Energy Capacity in Aging Tissue; Motor Function in Parkinson Disease

Contraindications

Documented hypersensitivity to riboflavin

High-dose (hundreds of milligrams) use during active anthracycline chemotherapy unless the oncology team agrees

Key Interactions

Probenecid

Anticholinergics (atropine, scopolamine; separate timing at high dose)

Phenothiazines (chlorpromazine) and tricyclic antidepressants (amitriptyline)

Tetracyclines (doxycycline, tetracycline; separate by at least 2 hours)

Barbiturates (phenobarbital, primidone) and heavy alcohol use

Oral contraceptives (ethinyl estradiol) and thyroid hormone (levothyroxine)

Magnesium and coenzyme Q10

Folate, vitamin B6, and vitamin B12

Iron

Risk & Side Effects

High: Yellow-Orange Urine

Low: Gastrointestinal Symptoms at High Dose

Speculative: Rare Hypersensitivity; Cutaneous Photosensitivity at High Oral Doses; Reduced Activity of Some Anthracycline Chemotherapy

Monitoring

Marker	Target	Why
EGRac	≤1.26 (optimal); 1.27–1.39 suboptimal; ≥1.40 deficient	Functional riboflavin status
Plasma riboflavin	No single longevity target; track rise from the person’s baseline	Direct circulating vitamin
Homocysteine	Functional often <8–10 µmol/L; many labs flag only >15	One-carbon output, TT-genotype response
MTHFR C677T	TT versus CC/CT (genotype, not a range)	Selects the 1.6–5 mg blood-pressure/homocysteine protocol
Blood pressure	Individual target; trial “goal” was ≤140/90 mmHg	Endpoint in TT hypertension trials
Hemoglobin / complete blood count	Individual baseline; pregnancy often aims hemoglobin ≥110 g/L	Anemia adjunct
Plasma pyridoxal 5'-phosphate (active vitamin B6)	Conventional often >30 nmol/L; falls when EGRac is high	Riboflavin-dependent B6 activation

Cadence: Repeat EGRac and homocysteine at 8–12 weeks, then every 6–12 months once stable, with blood pressure at the same visits in TT-genotype users

Qualitative Assessment

Migraine diary: attack days, duration, and pain score each month for at least 3 months
Energy and recovery: subjective only; not a stand-alone success rule
Urine color: confirms intake; not a disease marker
Skin, lips, and tongue: resolution of cheilosis (cracked lip corners) or glossitis (inflamed tongue) if those were present at baseline

Riboflavin for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment