What is the recommended dosage of riboflavin (Vitamin B2)?

Riboflavin Dosage Recommendations

For healthy adults, use 1.1-1.3 mg/day for maintenance; for suspected deficiency, immediately start 5-10 mg/day; and for migraine prophylaxis or mitochondrial disease, use 50-400 mg/day. 1

Standard Maintenance Dosing for Healthy Individuals

• Healthy adult males require 1.3 mg/day, while females require 1.1 mg/day 1
• Pregnant women need 1.4 mg/day, and lactating women require 1.6 mg/day 1
• Children over 12 months require 1.4 mg/day 1, 2
• Infants (preterm and term) require 0.15-0.2 mg/kg/day 1

Therapeutic Dosing for Deficiency States

When clinical signs of deficiency are present (oral-buccal lesions, angular stomatitis, seborrheic dermatitis, photophobia, or normochromic anemia), immediately escalate to 5-10 mg/day orally until recovery 1, 3, 2

• Do not delay supplementation while awaiting laboratory confirmation, as clinical deficiency can progress rapidly 1, 3, 2
• Riboflavin deficiency rarely occurs in isolation and frequently coexists with pyridoxine, folate, and niacin deficiencies 3, 2

High-Dose Therapeutic Dosing for Specific Conditions

Migraine Prophylaxis

• The American Academy of Neurology recommends 50-200 mg/day for migraine prophylaxis 1
• The most robust evidence supports 400 mg/day as the optimal dose, with 59% of patients achieving at least 50% reduction in headache days (number-needed-to-treat of 2.3) 4, 5
• This dose significantly reduces attack frequency and headache days compared to placebo, with excellent tolerability 4

Mitochondrial Disease and MADD

• For confirmed or suspected mitochondrial disease or multiple acyl-CoA dehydrogenase deficiency (MADD), use 50-200 mg/day 1, 2
• The National Institutes of Health supports this dosing range for these specific metabolic conditions 1

Special Population Dosing

Enteral and Parenteral Nutrition

• Standard enteral nutrition dosing is 1.2 mg/day (in 1500 kcal formulation) 3
• Parenteral nutrition requires 3.6-5 mg/day 3

High-Risk Populations Requiring Supplementation

• Patients with malabsorption syndromes, renal disease (especially hemodialysis or peritoneal dialysis), thyroid dysfunction, and diabetes require closer monitoring and often supplementation 1, 3
• Elderly patients who avoid dairy products are at increased risk for deficiency 1

Safety Profile and Monitoring

• Riboflavin has no established upper toxicity limit, and excess is excreted in urine 1
• At standard doses, the only typical adverse effect is yellow-colored urine 3, 2
• Minor adverse events at high doses (400 mg) are rare and include diarrhea and polyuria 4
• Repeatedly consumed pharmacologic doses exceeding 100 mg have potential to form toxic peroxides and hepato/cytotoxic tryptophan-riboflavin adducts, though clinical significance remains unclear 3

When to Monitor

• Routine monitoring is not necessary for patients receiving standard RDA doses 1, 2
• Assessment is only required when clinical suspicion of deficiency exists 1, 3, 2
• The most reliable functional assay is erythrocyte glutathione reductase activity coefficient (EGRAC), with ratios ≥1.40 indicating biochemical deficiency 1, 2

Critical Clinical Considerations

• Riboflavin is essential for metabolism of other B vitamins (B6, niacin, folate), and deficiency interferes with iron handling and absorption, contributing to anemia when iron intakes are low 1, 3, 2
• Riboflavin requirements increase with protein intake and energy metabolism 2
• Because riboflavin enhances iron absorption and mobilization from stores, deficiency may contribute to anemia particularly among women and children 3