Vitamin B2 (Riboflavin)

Essential B vitamin critical for energy production, antioxidant function, and cellular growth

Scientific nameRiboflavin FormulaC17H20N4O6 Molecular weight376.36 g/mol CAS83-88-5

85 absorption score

10 safety / 10

10 USD per month

6 documented interactions

Check it against something

Evidence level A

Vitamin B2 (Riboflavin) with:

94 out of 100

Works better together Take together — same timing window amplifies the synergy.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Energy metabolism support

Essential component of FAD and FMN coenzymes

Required for electron transport chain and Krebs cycle Evidence A-grade 1-2 weeks

Migraine prevention

May reduce migraine frequency by 50% in some people

Improves mitochondrial energy production in brain Evidence A-grade 12-16 weeks

Antioxidant support

Required for glutathione reductase enzyme function

Regenerates glutathione antioxidant system Evidence A-grade 2-4 weeks

Eye health

Protects against cataracts and supports vision

Antioxidant protection in lens and retina Evidence B-grade 8-12 weeks

Iron metabolism

Required for iron absorption and utilization

Needed for iron mobilization from stores Evidence A-grade 4-8 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Ashwagandha Stress management & energy 300-600mg A 75% Vitamin B12 (Cyanocobalamin) Energy & nerve support 250-1000 mcg A 70% Coenzyme Q10 (CoQ10) Heart health & cellular energy 100-200mg A 10% Phosphorus Bone health & energy metabolism 700-1250mg A 80% Vitamin B3 (Niacinamide) Energy & skin health (no flush) 100-1000 mg A 88% Berberine for Advanced Glucose Control and Metabolic Support Blood sugar control & metabolic support 1500mg daily (500mg x3) A 60%

Every pair we checked

12 combinations scored by the engine

Vitamin B2 (Riboflavin) + Caffeine No documented interaction either way No known interaction 70

Vitamin B2 (Riboflavin) + Creatine Monohydrate No documented interaction either way No known interaction 70

Vitamin B2 (Riboflavin) + Whey Protein No documented interaction either way No known interaction 70

Vitamin B2 (Riboflavin) + Turmeric No documented interaction either way No known interaction 70

Vitamin B2 (Riboflavin) + Lactase Improved calcium absorption when consuming dairy Works better together 82

Vitamin B2 (Riboflavin) + Bovine Collagen Essential for collagen synthesis and cross-linking Works better together 82

Vitamin B2 (Riboflavin) + DHA Prevents oxidation of DHA and enhances stability Works better together 82

Vitamin B2 (Riboflavin) + Vitamin D3 Riboflavin required for B6 activation Works better together 90

Vitamin B2 (Riboflavin) + Fish Oil (EPA/DHA) Protects fish oil from oxidation Works better together 90

Vitamin B2 (Riboflavin) + Calcium Carbonate Essential for calcium absorption and utilization Works better together 94

Vitamin B2 (Riboflavin) + Vitamin B3 (Niacinamide) Riboflavin required for niacin metabolism Works better together 99

Vitamin B2 (Riboflavin) + Iron Sulfate Both work together in energy metabolism Works better together 99

Dosage

Morning with food

Daily25-100 mg

Maintenance10-25 mg

Therapeutic100-400 mg

Migraine prevention400 mg

MaximumNo established upper limit

Before you take it

VeganYes

When to expect it

First Effects1-2 weeks for energy improvements

Peak Benefits12-16 weeks for migraine prevention

Deficiency Development1-2 months with inadequate intake

Toxicity OnsetNo known toxicity from oral intake

How to measure it

$60-100

MarkerErythrocyte glutathione reductase activity (EGRAC)

OptimalActivity coefficient <1.2

FrequencyOnly if deficiency suspected or therapeutic dosing

What people actually reported to the FDA

CAERS, 5 reports naming it as the suspect

Most reported effects

Chromaturia 2

Autism 1

Mitochondrial dna mutation 1

Alanine aminotransferase increased 1

Aspartate aminotransferase increased 1

Named as the suspect 5 reports of 23 that mention it at all

Serious outcome 75% hospitalisation, emergency room or worse

Other Serious or Important Medical Event3

Other Outcome1

Hospitalization1

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Absorption Very high 85 of 100 · best absorbed form of this compound

Delivered daily 53.1 mg

Cost per 100 mg delivered $0.63 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented

Niacin B3

Riboflavin required for niacin metabolism

Needed for converting tryptophan to niacin · level A

Vitamin B6

Riboflavin required for B6 activation

Needed for pyridoxine phosphate oxidase · level A

Iron

Both work together in energy metabolism

Riboflavin needed for iron mobilization · level A

What not to take with Vitamin B2 (Riboflavin)

3 documented

Alcohol

Reduces riboflavin absorption and increases excretion

Interferes with riboflavin transport and metabolism · moderate significance

Light Exposure

UV light rapidly destroys riboflavin

Photodegradation of the vitamin · significant for supplements significance

Boric Acid

May interfere with riboflavin utilization

Competes for binding sites · mild significance

Medication interactions

Discuss these with a pharmacist before combining

tricyclic-antidepressants Minor

May reduce riboflavin levels

What to do: Consider riboflavin supplementation

phenothiazines Minor

May increase riboflavin requirements

What to do: Monitor for deficiency signs

Available forms

bioavailability compared

Riboflavin 85

Riboflavin 5'-Phosphate (R5P) 90

Riboflavin: Natural form, Well-absorbed, Most research

Riboflavin 5'-Phosphate (R5P): Active coenzyme form, Better absorption, No conversion needed

Food sources

before you supplement

Beef liver 2.8 mg/100g · 90

Nutritional yeast 4.2 mg/100g · 85

Almonds 1.0 mg/100g · 80

Spinach 0.24 mg/100g · 75

Eggs 0.5 mg/100g · 85

Too little

deficiency signs

Cracked lips and mouth corners (cheilosis)
Sore throat and swollen tongue
Eye irritation and light sensitivity
Skin disorders and dermatitis
Fatigue and weakness
Anemia
Seborrheic dermatitis

Too much

toxicity signs

No known toxicity from oral intake
Bright yellow urine (harmless)
Possible photosensitivity at very high doses
No upper limit established
Excess excreted in urine

Who benefits most

migraine-sufferers

High-dose riboflavin reduces migraine frequency

400 mg daily

athletes

Increased energy metabolism and oxidative stress

25-100 mg daily

vegetarians-vegans

Lower intake from plant-based diets

25-50 mg daily

elderly

Reduced absorption and increased requirements

25-50 mg daily

pregnant-breastfeeding

Increased needs for fetal development

25-50 mg daily

Where to buy it

compare forms first

Look for Vitamin B2 (Riboflavin) at 25-100 mg per serving. The form that matters here is Riboflavin.

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What else affects it

Beyond other supplements

Alcohol

Reduces riboflavin absorption and increases excretion

Interferes with riboflavin transport and metabolism

How it works

Component of FAD and FMN coenzymes
Essential for electron transport chain
Required for Krebs cycle enzymes
Cofactor for glutathione reductase
Needed for fatty acid beta-oxidation
Required for other B vitamin activation

Key findings

what the evidence supports

Reduces migraine frequency by 50% at 400mg daily (Neurology 1998)
Essential for energy metabolism - established biochemistry
Deficiency common worldwide, especially in developing countries
Required for antioxidant glutathione system function

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Vitamin B2 (Riboflavin)?

Documented effects: Energy metabolism support; Migraine prevention; Antioxidant support; Eye health. Essential component of FAD and FMN coenzymes

How much Vitamin B2 (Riboflavin) should you take per day?

The common daily range is 25-100 mg. By goal — maintenance: 10-25 mg; therapeutic: 100-400 mg; migraine prevention: 400 mg; maximum: No established upper limit.

When is the best time to take Vitamin B2 (Riboflavin)?

Morning with food. First effects are typically reported within 1-2 weeks for energy improvements.

What are the side effects of Vitamin B2 (Riboflavin)?

At excessive doses: No known toxicity from oral intake, Bright yellow urine (harmless), Possible photosensitivity at very high doses, No upper limit established, Excess excreted in urine. Safety rating at normal doses is 10 out of 10.

What should you not take with Vitamin B2 (Riboflavin)?

Separate it from Alcohol, Light Exposure, Boric Acid by two to four hours. Reduces riboflavin absorption and increases excretion

Does Vitamin B2 (Riboflavin) interact with medications?

Documented interactions with tricyclic-antidepressants, phenothiazines. Discuss these with a pharmacist before combining.

How do you know if you need Vitamin B2 (Riboflavin)?

The marker is Erythrocyte glutathione reductase activity (EGRAC), optimal range Activity coefficient <1.2. Common deficiency signs: Cracked lips and mouth corners (cheilosis), Sore throat and swollen tongue, Eye irritation and light sensitivity, Skin disorders and dermatitis.

Taken for

62 Energy & Metabolism

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