Overview
Vitamin B2 (riboflavin) is a water-soluble vitamin essential for energy production, cellular function, and metabolism of fats, drugs, and steroids. It serves as a precursor for flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), cofactors involved in redox reactions and mitochondrial electron transport. Riboflavin also plays a role in homocysteine metabolism, with some evidence suggesting that supplementation may help lower plasma homocysteine levels, particularly when combined with other B vitamins such as folic acid and B12 [1][5]. However, trials evaluating B vitamin combinations for cardiovascular risk reduction have shown inconsistent results, with no significant benefit in high-risk populations [7][5]. In critically ill patients, including those with COVID-19, low-dose riboflavin supplementation (4 mg/day) did not significantly alter clinical or biochemical outcomes [6]. Evidence for cognitive benefits from B2 supplementation is lacking, as systematic reviews of B vitamins have not shown consistent improvements in cognitive function [3]. Overall, riboflavin deficiency is rare in well-nourished populations, and routine supplementation beyond recommended levels is not supported by current evidence for general health or disease prevention [2].
Dosage Guide
Recommended Daily Allowance
For generally healthy individuals
Therapeutic Doses
For treatment of specific conditions
Upper Intake Limit
Maximum safe daily intake
Not established mg— No tolerable upper intake level set by the Institute of Medicine due to low toxicity
Special Forms
Alternative forms for specific needs
For individuals with impaired conversion of riboflavin, potential use in supplementation with malabsorption or genetic polymorphisms
Clinical Notes
- High-dose riboflavin (400 mg/day) is generally well-tolerated and used for migraine prevention, but may cause bright yellow discoloration of urine (flavinuria).
- Riboflavin deficiency (ariboflavinosis) presents with sore throat, cheilosis, glossitis, and seborrheic dermatitis; often occurs with other B-vitamin deficiencies.
- Absorption is dose-dependent and saturable; high doses result in diminished absorption efficiency.
- Monitor homocysteine levels when using riboflavin in combination with folic acid and B12 for homocysteine-lowering strategies.
Research
Daily 1.3 mg riboflavin as part of a mixed B-vitamin supplement reduced plasma homocysteine in acutely ill older patients.
Review finds limited evidence supporting routine vitamin supplementation in healthy individuals, including B2.
Systematic review found no clear cognitive benefit from B6, B12, or folic acid supplementation; limited data on B2.
Multivitamin supplement including B2 showed promise in improving outcomes in persons with HIV.
Homocysteine-lowering with B vitamins did not reduce cardiovascular events in people with or without pre-existing CVD.
Supplementation with 4 mg riboflavin and other B vitamins had no significant effect on biochemical or clinical outcomes in critically ill COVID-19 patients.
Folic acid and B6/B12 supplementation did not reduce cardiovascular events in high-risk women.
Review discusses potential of micronutrients including B vitamins to modulate inflammation and oxidative stress in COVID-19, though clinical evidence is limited.
Products Containing Vitamin B2(6 reports)
Ortho B Complex is a high-potency B-complex supplement delivering 50 mg each of vitamins B1, B2, B3, B5, and B6, along with 200 mcg B12, 1,360 mcg folic acid (B9), 75 mcg biotin, 19 mg choline, and 50 mg inositol. The formulation emphasizes pharmacological doses of B vitamins, particularly those involved in energy metabolism, homocysteine regulation, and neurological function.
BioActive Complete B-Complex is a high-potency B-vitamin supplement designed to support energy metabolism, neurological function, and homocysteine regulation. The formulation features all eight B vitamins at doses that meet or exceed clinically studied levels for key indications, with particular emphasis on B1, B2, B3, B6, B9, and B12 for metabolic and neurological support.
This supplement delivers a high-dose of elemental iron (29 mg) as the primary active ingredient, formulated with cofactors such as vitamin C, riboflavin, copper, and biotin to support iron metabolism and red blood cell formation. The dose of iron is within the therapeutic range for treating iron deficiency, particularly in at-risk populations such as women of reproductive age and pregnant individuals.
This supplement delivers high-dose vitamin D (25µg/1000 IU) as a primary ingredient, supported by a full B-complex, vitamins C and E. The formulation is designed to support immune function, metabolic health, and antioxidant defense, with clinically relevant dosing of key micronutrients.
HYDROXYCUT HARDCORE LIQUID HEAT is a thermogenic weight management supplement with caffeine and cayenne pepper extract as its primary active ingredients. These compounds are clinically shown to enhance metabolic rate, reduce energy intake, and support fat oxidation. The formulation includes supporting doses of B-vitamins and green coffee bean extract to complement energy metabolism and cardiovascular health.
This multivitamin provides a comprehensive blend of essential vitamins at doses aligned with recommended dietary allowances and evidence-based clinical ranges. Vitamin D, B12, and folate are included at levels shown to support immune, neurological, and cardiovascular health, particularly in at-risk populations.