Riboflavin — Clinical Overview
| Indication | Form | Dose | Duration | Notes |
|---|
| Deficiency (mild) | Oral riboflavin | 5–10 mg/day | 6 weeks | Divided doses; poor absorption at high single doses |
| Ariboflavinosis (severe) | Oral/IV | 10–30 mg/day divided | Until recovery | Angular stomatitis, glossitis — dietary correction essential |
| Migraine prophylaxis | Oral riboflavin | 400 mg once daily | ≥3 months | Grade B evidence; benefit in 3–6 weeks |
| Pregnancy RDA | Oral | 1.4 mg/day | Throughout | Lactation: 1.6 mg/day |
| Neonatal jaundice (phototherapy) | Oral/IV | 0.1–0.3 mg/kg/day | During phototherapy | Phototherapy degrades riboflavin |
Ariboflavinosis in India
Riboflavin deficiency (ariboflavinosis) is common in India, particularly among low-income vegetarian populations with minimal dairy intake, schoolchildren, alcoholics, and those with chronic diarrhoea. Clinical signs: angular stomatitis, cheilosis, magenta/purple glossitis, scrotal/vulval dermatitis, and corneal vascularisation. Riboflavin is sensitive to light — store away from sunlight. Milk and dairy are the richest dietary sources.
Riboflavin for Migraine Prophylaxis
High-dose riboflavin 400 mg/day is a well-established non-pharmacological migraine prophylaxis option with Grade B evidence from randomised controlled trials. The mechanism involves improving mitochondrial energy metabolism. It takes 4–12 weeks for benefits to emerge. Side effect profile is excellent — the only notable effect is bright yellow/orange urine (harmless — warn patients). It can be combined with magnesium and coenzyme Q10 for additive benefit. Available OTC in India — very cost-effective migraine prophylaxis.
Absorption of Riboflavin
Riboflavin absorption is saturable — large single doses are poorly absorbed. Maximum absorption per dose is approximately 25–27 mg. For therapeutic doses above 30 mg/day, divide into 2–3 doses. Exception: migraine prophylaxis with 400 mg as a single daily dose is still clinically effective despite saturable absorption, as even partially absorbed amounts are therapeutically useful.
Normal Riboflavin Levels
Serum riboflavin: 6–39 mcg/dL. Erythrocyte Glutathione Reductase Activation Coefficient (EGRAC): <1.2 normal; 1.2–1.4 borderline; >1.4 deficient. Urine riboflavin: >80 mcg/g creatinine normal.
Frequently Asked Questions
What is the riboflavin dose for migraine prophylaxis?
Riboflavin 400 mg once daily for at least 3 months. Benefit is typically seen after 4–12 weeks. It is well-tolerated — the only side effect is bright yellow urine (benign, warn the patient). It can be combined with magnesium 400–600 mg/day and coenzyme Q10 for additive effects. Available OTC — cost-effective option for migraine prevention in Indian patients.
What is the dose of riboflavin for B2 deficiency / ariboflavinosis?
Mild-moderate deficiency: riboflavin 5–10 mg/day orally in divided doses × 6 weeks, then dietary correction. Severe ariboflavinosis: 10–30 mg/day in 2–3 divided doses until clinical recovery. For children: 2–4 mg/day; infants: 0.3–0.5 mg/day. Divide doses as absorption is limited to ~25 mg per dose. Dietary sources (milk, eggs, meat, leafy vegetables) should be optimised alongside supplementation.
Why does riboflavin cause yellow urine?
Excess riboflavin is excreted in urine, which turns bright yellow-orange — this is completely harmless and expected. Warn patients, especially those on high-dose migraine prophylaxis (400 mg/day), to avoid unnecessary alarm. The yellow colour normalises when supplementation is stopped.
What is the riboflavin dose in pregnancy?
RDA for riboflavin: 1.1–1.3 mg/day (adults); 1.4 mg/day during pregnancy; 1.6 mg/day during lactation. For deficiency in pregnancy: 5–10 mg/day orally. Riboflavin deficiency in pregnancy has been associated with pre-eclampsia risk and neonatal cataract. B-complex supplements containing riboflavin are routinely recommended during antenatal care in India.
Is riboflavin given IV or only orally in India?
Riboflavin is available for IV use as Riboflavin-5-phosphate (FMN). IV riboflavin is rarely needed but is used in severe malabsorption, patients on TPN (all TPN formulations should include riboflavin), ICU patients, and neonates on phototherapy (as phototherapy degrades riboflavin). Oral riboflavin is first-choice for virtually all clinical situations outside these exceptions.
What are the signs of riboflavin deficiency?
Ariboflavinosis signs include: angular stomatitis (cracks at corners of the mouth), cheilosis (cracking of lips), glossitis (magenta/purple tongue), scrotal or vulval dermatitis (seborrhoeic pattern), corneal vascularisation (in severe cases), and normocytic anaemia. These often coexist with other B-vitamin deficiencies. Common in Indian vegetarians with low dairy intake, alcoholics, and malnourished children.