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Medically reviewed by Last updated on Sep 3, 2020.


(RYE boe flay vin)

Index Terms

  • Lactoflavin
  • Vitamin B2
  • Vitamin G

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

B-2-400: 400 mg

Generic: 50 mg

Tablet, Oral:

Generic: 25 mg, 50 mg, 100 mg

Brand Names: U.S.

  • B-2-400 [OTC]

Pharmacologic Category

  • Vitamin, Water Soluble


Component of flavoprotein enzymes that work together, which are necessary for normal tissue respiration; also needed for activation of pyridoxine and conversion of tryptophan to niacin


Readily via GI tract; increased with food




9% eliminated unchanged in urine

Half-Life Elimination

Biologic: 66 to 84 minutes

Use: Labeled Indications

Dietary supplement

Off Label Uses

Prevention of migraine headache

Data from randomized, placebo- and active-controlled trials supports the use of riboflavin as a preventative treatment to decrease the frequency, duration, and severity of migraine headaches [Rahimdel 2015], [Shoenen 1998]. Additional trials may be necessary to further define the role of riboflavin in this condition.

Based on the American Headache Society and American Academy of Neurology guidelines for migraine prevention, riboflavin is probably effective for migraine prevention [AHS/AAN [Holland 2012]]. Similarly, guidelines from the Canadian Headache Society give riboflavin a strong recommendation based on low-quality evidence for use as a preventative treatment for migraines [CHS [Pringsheim 2012]].

Dosing: Adult

Dietary supplement: Oral: 100 mg once or twice daily

Prevention of migraine headache (off-label use): Oral: 400 mg once daily (Rahimdel 2015; Schoenen 1998)

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Dietary supplement: Infants, Children, and Adolescents: A multivitamin preparation is most commonly used for the provision of riboflavin supplementation in pediatric patients; the use of a single-ingredient riboflavin product as a daily supplement for the prevention of deficiency in pediatric patients is very rare. If single-ingredient riboflavin supplement is necessary, consult product labeling for appropriateness of product in infants and young children in particular.

Migraine headache, prevention: Limited data available, efficacy results variable: Children ≥ 8 years and Adolescents: Oral: 200 to 400 mg once daily; dosing based on a retrospective study of 41 patients (ages 8 to 18 years) who received 200 mg/day (n=21) or 400 mg/day (n=20) as prophylaxis for migraine and migraine-type headaches; results showed significant reduction in primary endpoint of frequency of headache attack; 68.4% of patients had a ≥50% decrease in headache frequency during treatment (Condò 2009). However, in a prospective, placebo-controlled study of 48 patients (ages 5 to 15 years), patients received 200 mg/day (n=27) or placebo (n=21) and in the treatment group (riboflavin) no benefit compared to placebo for migraine frequency or intensity was observed; a high placebo responder rate was also reported (MacLennan 2008).

Dietary Considerations

Dietary sources of riboflavin include liver, kidney, dairy products, green vegetables, eggs, whole grain cereals, yeast, and mushroom.

Dietary reference intake (IOM 1998):

1 to 6 months: Adequate intake: 0.3 mg/day

7 to 12 months: Adequate intake: 0.4 mg/day

1 to 3 years: RDA: 0.5 mg

4 to 8 years: RDA: 0.6 mg

9 to 13 years: RDA: 0.9 mg

14 to 18 years: RDA: Females: 1 mg; Males: 1.3 mg

≥19 years: RDA: Females: 1.1 mg; Males: 1.3 mg

Pregnancy: RDA: 1.4 mg

Lactation: RDA: 1.6 mg


Protect from light.

Drug Interactions

There are no known significant interactions.

Test Interactions

Large doses may interfere with urinalysis based on spectrometry; may cause false elevations in fluorometric determinations of catecholamines and urobilinogen

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

Frequency not defined: Genitourinary: Urine discoloration (yellow-orange)


Other warnings/precautions:

• Vitamin deficiency: Single vitamin deficiency is rare; evaluate for other deficiencies.

Pregnancy Considerations

Water-soluble vitamins cross the placenta. Riboflavin requirements may be increased in pregnant women compared to nonpregnant women (IOM 1998).

Patient Education

What is this drug used for?

• It is used to help growth and good health.

• It is used to treat or prevent riboflavin deficiency.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Urine discoloration

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine’s uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.