Vitamins & Supplements · Vitamin
Vitamin B2 (riboflavin)
Riboflavin · also called Vitamin B2, vitamin B-2
Riboflavin is a B vitamin your body needs every day to release energy from food and to make red blood cells. A true shortage is uncommon where food is plentiful. In trials, high-dose supplements lowered migraine attacks in adults, but the evidence is low certainty. No poisoning from riboflavin is known, but high-dose supplements have little long-term safety data, so ask a doctor or pharmacist first.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Vitamin B2 (riboflavin)
Riboflavin (vitamin B2) is a water-soluble B vitamin the body uses every day and does not store much of. Milk, eggs, mushrooms and almonds are good sources. Low levels cause anaemia and mouth, lip and skin problems. High-dose supplements reduced migraine in small trials, with low certainty. No poisoning is known, but long-term safety of high doses is not well studied.
What it is
Riboflavin is vitamin B2. It is water soluble, which means leftover amounts leave the body in the urine and the body keeps only a small reserve. It has to be eaten regularly.
The body turns riboflavin into two helper molecules, FMN and FAD. Many chemical reactions in cells need them, including those that release energy from carbohydrates, proteins and fats. MedlinePlus also says riboflavin is important for body growth and for making red blood cells.
We did not read a source on the history of its discovery, so this page does not cover it.
Where you find it in food
The NHS lists milk, eggs, fortified breakfast cereals, mushrooms and plain yoghurt as good sources. MedlinePlus adds green leafy vegetables, lean meats, organ meats such as liver and kidney, legumes and nuts, and says breads and cereals are often fortified.
USDA FoodData Central gives these amounts per 100 g: whole milk 0.169 mg (a cup of 244 g works out at about 0.41 mg), plain low-fat yogurt 0.214 mg (a cup of 245 g, about 0.52 mg), almonds 1.138 mg (an ounce, 28 g, about 0.32 mg), cheddar cheese 0.428 mg and raw spinach 0.19 mg. Portion figures are our arithmetic from USDA gram weights.
Light, including UV light, destroys riboflavin, so milk and other riboflavin-rich foods are best kept out of direct sunlight. These numbers describe the foods. They are not advice on how much to eat or take.
What the research shows
Low riboflavin: severe shortage causes anaemia, mouth or lip sores, skin problems, a sore throat and swollen mucous membranes. It is uncommon in the US because the vitamin is plentiful in food.
Migraine: a 1998 trial of 55 people found fewer attacks (p = 0.005) and headache days (p = 0.012) than placebo; 59% versus 15% had at least half fewer headache days. A 2022 pooled analysis of 9 trials (673 people) found fewer migraine days, attacks and pain, but the trials were very different from each other. A 2025 analysis of supplement trials found riboflavin lowered attack frequency by 1.34 attacks. We rate this low certainty.
Anaemia: a 2000 review reports that riboflavin improves the blood-count response to iron. A 2026 review says low riboflavin is common in pregnancy and that trials in low- and middle-income countries showed benefit. The authors say the role is under-investigated.
Blood pressure: in 31 patients with the MTHFR 677TT gene variant, riboflavin lowered systolic blood pressure by 9.2 mm Hg and diastolic by 6.0 mm Hg. Small trials, one research group.
Eyes and rare diseases: people who ate more riboflavin had lower odds of cataract in a large observational study. In the rare disease MADD, some patients respond to riboflavin according to case series and reviews.
Food versus supplements
The migraine and anaemia findings are for riboflavin supplements. The cataract link is for riboflavin eaten in food. Food gives much smaller amounts than the migraine trials used, and it brings other nutrients with it. A result for one should not be assumed for the other.
Many B-complex and multivitamin products also contain riboflavin. They are different products and are not covered here.
At a glance
Traditional uses history, not proof
- A nutrient, not a traditional remedy
- Eaten in everyday foods such as milk, eggs and mushrooms
Studied for research
- Preventing and correcting low riboflavin, moderate certainty (agency statements)
- Migraine prevention, low certainty (small trials that differ a lot)
- Anaemia linked to low riboflavin, low certainty (reviews)
- Blood pressure in people with the MTHFR 677TT gene variant, low certainty (small trials)
- Cataract (observational link), very low certainty
- Rare inherited disorders such as MADD, low certainty (case series)
- Extra energy when intake is already enough, not enough evidence
Main compounds
- Riboflavin
- FMN (flavin mononucleotide)
- FAD (flavin adenine dinucleotide)
Common forms
- Riboflavin in food (milk, eggs, mushrooms, almonds)
- Riboflavin as a single supplement (used in the migraine trials)
- B-complex and multivitamin products contain riboflavin among other vitamins and are not covered here
Research links: 1998 trial: riboflavin and migraine · 2022 review: vitamin B2 and migraine (9 trials) · MedlinePlus: Riboflavin · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Riboflavin (vitamin B2). A vitamin (a chemical compound), not a species.
- Synonyms
- Vitamin B2; Vitamin B-2
- Common names
- Riboflavin (English); Vitamin B2 (English); Riboflavina (Spanish); Vitamina B2 (Spanish)
- Family or group
- B vitamins (water-soluble vitamins)
- Harvest and processing
- Not researched: how supplement riboflavin is made was not read.
- Look-alikes and adulterants
- Name: Thiamin (vitamin B1); Note: Another B vitamin with its own page.; Name: Niacin (vitamin B3); Note: Another B vitamin that works with riboflavin in energy metabolism.; Name: Folate (vitamin B9); Note: Linked to riboflavin through the MTHFR enzyme.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Riboflavin PubChem 493570 | vitamin (isoalloxazine ring with a ribityl side chain) | See the nutrition note for amounts in foods. | The vitamin itself; the body makes it into FMN and FAD. 12 2 | Human data |
| Flavin mononucleotide (FMN) PubChem 643976 | coenzyme form of riboflavin | Not researched. | A riboflavin helper molecule (cofactor) for oxidation-reduction reactions, per the 2026 review. 2 | Human data |
| Flavin adenine dinucleotide (FAD) | coenzyme form of riboflavin | Not researched. | The other riboflavin helper molecule; needed, for example, by the MTHFR enzyme and by the electron-transfer system in mitochondria. 2 5 6 | Human data |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Cell energy and oxidation-reduction reactions | Flavoproteins (many) | Riboflavin is made into FMN and FAD, which many oxidation-reduction reactions need. MedlinePlus says it aids the release of energy from carbohydrates, proteins and fats. 2 12 | Human data |
| Iron release from storage | Ferritin | The 2026 review says riboflavin cofactors are needed to release iron from storage ferritin for making red blood cells, and calls this the best-supported mechanism for how low riboflavin may cause anaemia. 2 3 | Human data |
| Folate and homocysteine chemistry (one-carbon metabolism) | MTHFR enzyme (677C to T variant) | Riboflavin is the helper for the MTHFR enzyme. In adults with the TT variant, riboflavin raised plasma SAM and cystathionine in a 16-week trial. 6 10 | Human data |
| Electron transfer in mitochondria | ETFDH (ETF-QO) | ETF-QO carries electrons in the inner mitochondrial membrane. Changes in the ETFDH gene are often tied to riboflavin-responsive MADD. 5 11 | Human data |
| Migraine | Not specified in the sources read | The 1998 trial authors suggested that a deficit of mitochondrial energy metabolism may play a role in migraine. Not confirmed. 7 | Hypothesis |
Absorption, metabolism and elimination
- Absorption
- Not found in the sources read.
- Distribution
- Not found.
- Metabolism
- Made into FMN and FAD (2026 review).
- Elimination
- Water soluble; leftover amounts leave the body in the urine (MedlinePlus).
- Bioavailability
- Not established in the sources read, including from food versus supplements.
Isolated compounds versus whole extracts
The migraine and anaemia trials used riboflavin supplements. The cataract link is for riboflavin eaten in food. Food gives much smaller amounts than the migraine trials used, and food also contains many other nutrients. A finding for one does not carry over to the other.
Nutritional composition
Food sources named by the NHS and MedlinePlus: milk, eggs, fortified breakfast cereals, mushrooms, plain yoghurt, dairy products, green leafy vegetables, lean meats, organ meats such as liver and kidney, legumes and nuts. USDA FoodData Central (SR Legacy, April 2018, our saved copy) gives riboflavin per 100 g: whole milk 0.169 mg (1 cup, 244 g, about 0.41 mg), plain low-fat yogurt 0.214 mg (1 cup, 245 g, about 0.52 mg), almonds 1.138 mg (1 oz, 28.35 g, about 0.32 mg), cheddar cheese 0.428 mg, raw spinach 0.19 mg. Portion figures are our arithmetic from USDA gram weights. Light destroys riboflavin. These are food facts, not advice on how much to eat.
1 moderate certainty4 low certainty1 very low certainty1 not enough evidence
What was looked at
The 7 benefits and uses checked for Vitamin B2 (riboflavin), each with how strong the evidence is. Tap one to open it.
- Preventing and correcting low riboflavinModerate certainty
- Migraine prevention (high-dose supplements)Low certainty
- Anaemia linked to low riboflavin (alongside iron)Low certainty
- Blood pressure in people with the MTHFR 677TT gene variantLow certainty
- Cataract and healthy eyes (food intake, observational)Very low certainty
- Rare inherited disorders that respond to riboflavin (specialist care)Low certainty
- Extra energy or less tiredness in people who are not short of riboflavinNot enough evidence
Lab markers tracked in the studies
Migraine attack frequency and headache daysHaemoglobin and anaemiaBlood pressure (systolic and diastolic)SAM and cystathionine (folate-related blood chemicals)Lens opacity (cataract grade)
What is Vitamin B2 (riboflavin) good for?
The main studied uses and how strong the evidence is for each. Most of the research is on people who were short of riboflavin or on high-dose supplements, which are not the same as getting riboflavin from food.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Preventing and correcting low riboflavin
Moderate certaintyRiboflavin is a vitamin the body needs every day. It helps release energy from food, helps make red blood cells and helps keep skin, eyes and nerves healthy. A true shortage is uncommon in the United States, but it causes anaemia, mouth or lip sores, skin problems and a sore throat. A supplement corrects a shortage. No trial we read shows extra benefit when intake is already enough.
2 studiesRiboflavin taken by mouth as a supplement. The amounts tested in tria…
Studies, doses and limits
What the trials found
We read two health agency summaries (NLM MedlinePlus, reviewed January 2025, and the UK NHS, last reviewed August 2020). Neither gives trial numbers. We did not read an original deficiency trial.
Results
Established as a nutrient. A shortage is uncommon in the US because the vitamin is plentiful in food. Both agencies say a varied diet should supply what is needed. The agencies do not describe any extra benefit from supplements for people who already get enough.
Effect sizes as reported
No effect sizes: these are agency statements, not trial results.
Why this rating
Moderate. The role of riboflavin is long established and consistent across the agency pages. But we read summaries, not original trials, so we cannot rate the size of any effect.
Form and dose studied
Riboflavin taken by mouth as a supplement. The amounts tested in trials are listed in the studies table; they are research settings, not advice. Food gives much smaller amounts than the migraine trials used, and a supplement is not the same thing as eating riboflavin-rich food.
Who was studied
People who do not get enough riboflavin. People who get enough were not shown to gain energy or skin benefits.
Limits
No trial was read that tests extra riboflavin for energy, skin or eyes in people who are not short of it. The NHS page review date (August 2023) has passed.
Why researchers looked
Riboflavin is an essential nutrient, so the main question is what happens when someone gets too little.
Proposed mechanism Established physiology
Riboflavin is made into two helper molecules, FAD and FMN, that many energy-making and other chemical reactions in cells need.
A proposed mechanism does not show that the effect happens in people.
No known poisoning (MedlinePlus). See the safety tab for what is and is not known about high-dose supplements.
Migraine prevention (high-dose supplements)
Low certaintySeveral trials gave people with migraine a high dose of riboflavin for about three months. A 2022 pooled analysis of nine trials (673 people) found fewer migraine days, shorter attacks, fewer attacks and lower pain scores. The trials differed a lot from each other, they were small, and the amounts were far above what food gives. It is an option to discuss with a doctor, not a cure.
3 studiesRiboflavin taken by mouth as a supplement. The amounts tested in tria…
Studies, doses and limits
What the trials found
In a 55-person randomised placebo-controlled trial (1998), riboflavin beat placebo for attack frequency (p = 0.005) and headache days (p = 0.012). A 2022 meta-analysis of 8 randomised trials and 1 controlled trial (673 people) and a 2025 meta-analysis of 22 supplement trials both found fewer attacks with riboflavin.
Results
A real and fairly consistent reduction in migraine in adults, but the trials vary widely in size and results. Adverse effects were minor in the 1998 trial.
Effect sizes as reported
1998 trial: at least half fewer headache days in 59% of the riboflavin group and 15% of the placebo group (number needed to treat 2.3). 2022 meta-analysis: migraine days p = 0.005 (I2 = 89%), duration p = 0.003, frequency p = 0.001 (I2 = 65%), pain score p = 0.015 (I2 = 84%); no pooled effect size in the abstract. 2025 meta-analysis: attack frequency mean difference -1.34 attacks.
Why this rating
Low. Two pooled analyses and one placebo-controlled trial agree on a benefit, but the trials are small, the results differ a lot between trials (I2 up to 89%), and the abstracts give no GRADE rating for riboflavin. We rate it low, not as proof.
Form and dose studied
Riboflavin taken by mouth as a supplement. The amounts tested in trials are listed in the studies table; they are research settings, not advice. Food gives much smaller amounts than the migraine trials used, and a supplement is not the same thing as eating riboflavin-rich food.
Who was studied
Adults with migraine. The 2025 analysis found no significant effect on other outcomes in adults for most supplements; children were studied separately and are not covered here.
Limits
Small trials, wide differences between them, short follow-up (about 3 months), a single trial with a strong result. No trial compared riboflavin with a standard migraine drug in the abstracts we read. Many studies did not control for other treatments.
Why researchers looked
One idea is that migraine involves a shortfall of energy production in brain cells, and riboflavin helps that energy machinery work. This is a hypothesis, not proven.
Proposed mechanism Hypothesis
Riboflavin is a helper for the cell's energy machinery (mitochondria). The authors of the first trial suggested a deficit of mitochondrial energy metabolism may play a role in migraine. Not confirmed.
A proposed mechanism does not show that the effect happens in people.
Minor effects only in the 1998 trial: diarrhoea and frequent urination (polyuria) in the riboflavin group, stomach cramps in the placebo group. Ask a doctor before using any supplement with a migraine drug. Sudden, severe or new headaches need urgent medical care.
Anaemia linked to low riboflavin (alongside iron)
Low certaintyRiboflavin helps the body handle iron, and severe shortage can come with anaemia. A 2000 review reports riboflavin boosts the blood-count response to iron. A 2026 review says trials in pregnant women in low- and middle-income countries showed benefits for anaemia. This applies when riboflavin is low and does not replace testing for the cause of anaemia.
2 studiesRiboflavin taken by mouth as a supplement. The amounts tested in tria…
Studies, doses and limits
What the trials found
A 2000 systematic review of vitamin trials and a 2026 narrative review, both read as abstracts only. The reviews do not give pooled numbers in their abstracts.
Results
Reviewers report riboflavin improves the response to iron and that low riboflavin may account for part of anaemia in some groups. They also say the overall public-health effect of vitamin supplements on anaemia is not clear.
Effect sizes as reported
No numbers in either abstract.
Why this rating
Low. Two reviews agree on the idea, but one is from 2000 and one is a narrative review, neither abstract gives trial numbers, and the authors themselves call the picture unclear.
Form and dose studied
Riboflavin taken by mouth as a supplement. The amounts tested in trials are listed in the studies table; they are research settings, not advice. Food gives much smaller amounts than the migraine trials used, and a supplement is not the same thing as eating riboflavin-rich food.
Who was studied
People with low riboflavin status, especially pregnant women in low- and middle-income countries. Not shown for people with normal riboflavin.
Limits
Abstract-level reading only; no individual trial was checked. Iron deficiency is the most common nutritional cause of anaemia, and anaemia has many other causes.
Why researchers looked
Riboflavin helper molecules are needed to release iron from storage (ferritin) for making red blood cells.
Proposed mechanism Mechanism reviewed
Riboflavin forms (FAD, FMN) are needed to release iron from the storage protein ferritin. The 2026 review calls this the best-supported explanation.
A proposed mechanism does not show that the effect happens in people.
Anaemia needs a doctor's check for the cause. Do not treat it yourself with vitamins alone.
Blood pressure in people with the MTHFR 677TT gene variant
Low certaintySome people carry two copies of a common gene variant (MTHFR 677TT). A 2020 paper says it is linked to a 24% to 87% higher risk of high blood pressure. In small trials from one research group, a small riboflavin supplement lowered blood pressure in people with this variant, by about 9 mm Hg (top number) and 6 mm Hg (bottom number). It was tested in 31 patients with heart disease. It has not been shown for people in general.
2 studiesRiboflavin taken by mouth as a supplement. The amounts tested in tria…
Studies, doses and limits
What the trials found
A 2012 placebo-controlled crossover trial followed 31 TT patients (83 patients in total) for 16 weeks of riboflavin or placebo; a 2020 report from the same programme measured blood chemicals in 115 adults.
Results
Systolic blood pressure fell 9.2 mm Hg and diastolic 6.0 mm Hg with riboflavin in people with the TT variant. Blood levels of SAM and cystathionine also rose.
Effect sizes as reported
Systolic -9.2 (SD 12.8) mm Hg, p = 0.001; diastolic -6.0 (SD 9.9) mm Hg, p = 0.003. SAM p = 0.008; cystathionine p = 0.045.
Why this rating
Low. The result comes from small trials from one research group, in one patient group, and has not been shown in the general population. Blood pressure is a measured marker, which is useful, but the group sizes were small.
Form and dose studied
Riboflavin taken by mouth as a supplement. The amounts tested in trials are listed in the studies table; they are research settings, not advice. Food gives much smaller amounts than the migraine trials used, and a supplement is not the same thing as eating riboflavin-rich food.
Who was studied
Adults with cardiovascular disease and the MTHFR 677TT variant. The result is specific to this gene group, and the gene is not tested in everyday care.
Limits
Only 31 people with the TT variant. Same research group for both trials. Not shown to prevent heart attack or stroke. The authors say it needs to be confirmed in the general population.
Why researchers looked
The MTHFR enzyme needs riboflavin to work, and the TT variant makes the enzyme work less well.
Proposed mechanism Human biomarker
Riboflavin is the helper for the MTHFR enzyme. In TT adults, riboflavin raised the chemicals SAM and cystathionine, which suggests it changes folate-related chemistry. Whether this explains the blood pressure change is not known.
A proposed mechanism does not show that the effect happens in people.
Blood pressure medicines should not be changed without a doctor.
Cataract and healthy eyes (food intake, observational)
Very low certaintyIn a large eye study (3,115 people followed for about ten years), people who ate more riboflavin in food were less likely to have early lens cloudiness (cataract) at the start. This is a link, not proof. It was about riboflavin in food, not supplements.
1 studiesDietary riboflavin from food only. The study did not test a riboflavi…
Studies, doses and limits
What the trials found
A 2015 analysis of the Age-Related Eye Disease Study (AREDS Report 37) of food questionnaires and lens photographs.
Results
People in the highest fifth of riboflavin intake had lower odds of mild nuclear, moderate nuclear and mild cortical cataract at the start than the lowest fifth.
Effect sizes as reported
Moderate nuclear cataract OR 0.62 (95% CI 0.43 to 0.90); mild nuclear OR 0.78 (0.63 to 0.97); mild cortical OR 0.80 (0.65 to 0.99).
Why this rating
Very low. This is an observational link in people who were already in an eye study. Eating more riboflavin may go with other differences in diet or health. Many nutrients were tested, and the riboflavin result was for the start of the study.
Form and dose studied
Dietary riboflavin from food only. The study did not test a riboflavin supplement.
Who was studied
Adults aged 55 to 80 in the AREDS study.
Limits
Cannot show cause. Food questionnaires are imprecise. No trial of riboflavin supplements for cataract was read.
Why researchers looked
The NHS says riboflavin helps keep the eyes healthy. How it might protect the lens was not explained in the sources we read.
Proposed mechanism Not tested
Not tested in the studies read.
A proposed mechanism does not show that the effect happens in people.
None specific.
Rare inherited disorders that respond to riboflavin (specialist care)
Low certaintyA rare inherited disease called MADD (multiple acyl-CoA dehydrogenase deficiency) affects how the body handles fats and proteins. In some patients, riboflavin helps, in what doctors call riboflavin-responsive MADD. The evidence is from small hospital case series and reviews. This is treated by specialist doctors, not by people on their own.
3 studiesDoctors may use riboflavin with other treatments (for example L-carni…
Studies, doses and limits
What the trials found
A 25-patient hospital series (2019), a 19-adult series from Scotland (2025) and a 2021 review. All were read as abstracts.
Results
Patients who respond to riboflavin generally do well, though life-threatening complications still occurred. In the Scottish series all 19 adults improved to a variable degree after riboflavin, nutrition advice and advice to stop sertraline together.
Effect sizes as reported
No controlled effect size; descriptive case-series results.
Why this rating
Low. These are case series and reviews with no comparison group. In the Scottish series three things changed at once, so the part played by riboflavin alone is unknown. The condition is rare.
Form and dose studied
Doctors may use riboflavin with other treatments (for example L-carnitine, coenzyme Q10 and a low-fat, low-protein diet) in this rare disease; the abstracts we read do not give amounts.
Who was studied
Patients with confirmed or suspected MADD or MADD-like muscle disease. Not for the general public.
Limits
Retrospective and uncontrolled. Diagnosis is often delayed (median two years in responders in one series).
Why researchers looked
The faulty enzyme (ETF-QO) uses riboflavin-based helper molecules. Extra riboflavin may help the enzyme work in some gene variants.
Proposed mechanism Human case series
Riboflavin forms (FAD) are part of the electron-transfer system in mitochondria. Some gene changes in ETFDH are riboflavin-responsive.
A proposed mechanism does not show that the effect happens in people.
Unexplained muscle weakness or pain needs a doctor's check; this disease is diagnosed with lab tests, not by trying vitamins.
Extra energy or less tiredness in people who are not short of riboflavin
Not enough evidenceRiboflavin helps the body release energy from food, so people often ask if extra riboflavin gives more energy. We found no trial showing it does in people who already get enough. Tiredness can also be a sign of anaemia or other illness, so ask a doctor.
2 studiesRiboflavin taken by mouth as a supplement. The amounts tested in tria…
Studies, doses and limits
What the trials found
No trial of extra riboflavin for energy or tiredness in people who are not short of it was found in the sources we read.
Results
Not tested in the sources read.
Why this rating
Insufficient. We found no trial. This is a gap in the evidence, not proof that it does not work.
Form and dose studied
Riboflavin taken by mouth as a supplement. The amounts tested in trials are listed in the studies table; they are research settings, not advice. Food gives much smaller amounts than the migraine trials used, and a supplement is not the same thing as eating riboflavin-rich food.
Limits
No evidence either way.
Why researchers looked
Because riboflavin helps energy metabolism, people expect extra to help. In a person who is not short, the body already has what it needs.
Proposed mechanism Established physiology
Riboflavin helps the body release energy from carbohydrates, proteins and fats (MedlinePlus, NHS). That does not mean extra gives extra energy.
A proposed mechanism does not show that the effect happens in people.
None specific.
Connections to the rest of health
How Vitamin B2 (riboflavin) connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Energy Boost | Demonstrated clinical effect | Moderate certainty | Preventing and correcting low riboflavin: Riboflavin is a vitamin the body needs every day. It helps release energy from food, helps make red blood cells and helps keep skin, eyes and nerves healthy. A true shortage is uncommon in the United States, but it causes anaemia, mouth or lip sores, skin problems and a sore throat. A supplement corrects a shortage. No trial we read shows extra benefit when intake is already enough. | 12 13 |
| Healthy Skin | Demonstrated clinical effect | Moderate certainty | Preventing and correcting low riboflavin: Riboflavin is a vitamin the body needs every day. It helps release energy from food, helps make red blood cells and helps keep skin, eyes and nerves healthy. A true shortage is uncommon in the United States, but it causes anaemia, mouth or lip sores, skin problems and a sore throat. A supplement corrects a shortage. No trial we read shows extra benefit when intake is already enough. | 12 13 |
| Brain Health | Low certainty | Migraine prevention (high-dose supplements): Several trials gave people with migraine a high dose of riboflavin for about three months. A 2022 pooled analysis of nine trials (673 people) found fewer migraine days, shorter attacks, fewer attacks and lower pain scores. The trials differed a lot from each other, they were small, and the amounts were far above what food gives. It is an option to discuss with a doctor, not a cure. | 7 1 8 | |
| Energy Boost | Low certainty | Anaemia linked to low riboflavin (alongside iron): Riboflavin helps the body handle iron, and severe shortage can come with anaemia. A 2000 review reports riboflavin boosts the blood-count response to iron. A 2026 review says trials in pregnant women in low- and middle-income countries showed benefits for anaemia. This applies when riboflavin is low and does not replace testing for the cause of anaemia. Rare inherited disorders that respond to riboflavin (specialist care): A rare inherited disease called MADD (multiple acyl-CoA dehydrogenase deficiency) affects how the body handles fats and proteins. In some patients, riboflavin helps, in what doctors call riboflavin-responsive MADD. The evidence is from small hospital case series and reviews. This is treated by specialist doctors, not by people on their own. | 3 2 11 9 5 | |
| Blood Pressure Support | Low certainty | Blood pressure in people with the MTHFR 677TT gene variant: Some people carry two copies of a common gene variant (MTHFR 677TT). A 2020 paper says it is linked to a 24% to 87% higher risk of high blood pressure. In small trials from one research group, a small riboflavin supplement lowered blood pressure in people with this variant, by about 9 mm Hg (top number) and 6 mm Hg (bottom number). It was tested in 31 patients with heart disease. It has not been shown for people in general. | 10 6 | |
| Heart Health | Low certainty | Blood pressure in people with the MTHFR 677TT gene variant: Some people carry two copies of a common gene variant (MTHFR 677TT). A 2020 paper says it is linked to a 24% to 87% higher risk of high blood pressure. In small trials from one research group, a small riboflavin supplement lowered blood pressure in people with this variant, by about 9 mm Hg (top number) and 6 mm Hg (bottom number). It was tested in 31 patients with heart disease. It has not been shown for people in general. | 10 6 | |
| Healthy Vision | Very low certainty | Cataract and healthy eyes (food intake, observational): In a large eye study (3,115 people followed for about ten years), people who ate more riboflavin in food were less likely to have early lens cloudiness (cataract) at the start. This is a link, not proof. It was about riboflavin in food, not supplements. | 4 | |
| Energy Boost | Not enough evidence | Extra energy or less tiredness in people who are not short of riboflavin: Riboflavin helps the body release energy from food, so people often ask if extra riboflavin gives more energy. We found no trial showing it does in people who already get enough. Tiredness can also be a sign of anaemia or other illness, so ask a doctor. | 12 13 | |
| Reduce Fatigue | Not enough evidence | Extra energy or less tiredness in people who are not short of riboflavin: Riboflavin helps the body release energy from food, so people often ask if extra riboflavin gives more energy. We found no trial showing it does in people who already get enough. Tiredness can also be a sign of anaemia or other illness, so ask a doctor. | 12 13 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Energy Fatigue | Biological association | Moderate certainty | Studied for: Preventing and correcting low riboflavin Studied for: Anaemia linked to low riboflavin (alongside iron) | 12 13 3 2 |
| Skin Hair Beauty | Biological association | Moderate certainty | Studied for: Preventing and correcting low riboflavin | 12 13 |
| Nervous System | Biological association | Moderate certainty | Studied for: Preventing and correcting low riboflavin Studied for: Migraine prevention (high-dose supplements) | 12 13 7 1 8 11 9 5 |
| Brain Health | Biological association | Low certainty | Studied for: Migraine prevention (high-dose supplements) | 7 1 8 |
| Blood Health | Biological association | Low certainty | Studied for: Anaemia linked to low riboflavin (alongside iron) | 3 2 |
| Cardiovascular System | Biological association | Low certainty | Studied for: Blood pressure in people with the MTHFR 677TT gene variant | 10 6 |
| Sensory System | Biological association | Very low certainty | Studied for: Cataract and healthy eyes (food intake, observational) | 4 |
| Musculoskeletal System | Biological association | Low certainty | Studied for: Rare inherited disorders that respond to riboflavin (specialist care) | 11 9 5 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Riboflavin deficiency | Established | Severe shortage can cause anaemia, mouth or lip sores, skin problems, a sore throat and swollen mucous membranes (MedlinePlus). Severe shortage can cause anaemia, mouth or lip sores, skin problems and a sore throat. Preparation or compound: Riboflavin (vitamin B2) |
12 | |
| Anaemia | Low certainty review evidence | Low riboflavin may contribute to anaemia and may weaken the response to iron (2000 and 2026 reviews). Preparation or compound: Riboflavin (vitamin B2) |
3 2 | |
| Migraine | Low certainty trial evidence | Pooled trials found fewer migraine attacks and days; minor stomach and urine effects in one trial. High-dose riboflavin supplements lowered migraine attacks in small trials. Preparation or compound: High-dose riboflavin supplements |
7 1 8 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Migraine attack frequency and headache days | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 7 1 8 |
| Haemoglobin and anaemia | Biological association | Low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 3 2 |
| Blood pressure (systolic and diastolic) | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 10 |
| SAM and cystathionine (folate-related blood chemicals) | Biological association | Low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 6 |
| Lens opacity (cataract grade) | Biological association | Very low certainty | Measured in trials: lowered (observational). A lab change is not the same as a health benefit. | 4 |
J. Genes, receptors and enzymes
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| MTHFR (677C to T variant) | Preliminary mechanism | Human | A 2020 paper says the TT genotype is linked to a 24% to 87% higher risk of high blood pressure; riboflavin is the MTHFR helper and lowered blood pressure in TT adults in small trials. | 6 10 |
| ETFDH | Preliminary mechanism | Human | Changes in this gene are often tied to riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency. | 5 11 |
K. Biological pathways
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Riboflavin | Biological association | Human | The vitamin itself; the body makes it into FMN and FAD. | 12 2 |
| Flavin mononucleotide (FMN) | Biological association | Human | A riboflavin helper molecule (cofactor) for oxidation-reduction reactions, per the 2026 review. | 2 |
| Flavin adenine dinucleotide (FAD) | Biological association | Human | The other riboflavin helper molecule; needed, for example, by the MTHFR enzyme and by the electron-transfer system in mitochondria. | 2 5 6 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).
Evidence at a glance: what changed in 4 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Vitamin B2 (riboflavin). Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing riboflavin summary, read the MedlinePlus and NHS pages in full, used saved USDA FoodData Central data for food amounts and re-read PubMed abstracts for the trials and reviews. Only abstracts were read for studies. The NIH Office of Dietary Supplements page could not be opened. Items we could not verify are flagged in the research gaps.
Study library: every study we checked 19
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Chen 2022 Effect of Vitamin B2 supplementation on migraine prophylaxis: a systematic review and meta-analysis. Nutr Neurosci · PMID 33779525 · DOI |
Meta-analysis |
673 People with migraine in 8 randomised trials and 1 controlled clinical trial (673 people in all) |
Riboflavin (vitamin B2) supplements Riboflavin (vitamin B2) by mouth 400 mg a day (the amount the authors name in their conclusion) About 3 months · vs Placebo or control groups |
Riboflavin supplements lowered migraine days (p = 0.005, I2 = 89%), duration (p = 0.003, I2 = 0), frequency (p = 0.001, I2 = 65%) and pain score (p = 0.015, I2 = 84%). Significant reductions on all four measures; the abstract gives no pooled size of effect (Not given in the abstract) Methods, limits and fundingOutcomes: Migraine days, duration, frequency and pain score Limitations: Trials differed a lot from each other (I2 of 89% for migraine days, 84% for pain score). Searches ended in March 2019. Small trials. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Duffy 2026 Anaemia during pregnancy: could riboflavin deficiency be implicated? Proc Nutr Soc · PMID 39540254 · DOI |
Narrative review |
Pregnant women in studies reviewed (observational studies in high-income countries; randomised trials in low- and middle-income countries) | Riboflavin status and riboflavin supplements in pregnancy Riboflavin (vitamin B2) by mouth Not given in the abstract Not given in the abstract |
The authors report that anaemia affects more than 36% of pregnancies worldwide, that mild (functional) riboflavin deficiency is widespread, including in high-income countries, and that limited observational evidence links low riboflavin status with more anaemia. They say randomised trials in pregnant women from low- and middle-income countries showed benefits on blood status and anaemia. They name an effect on iron handling as the best-supported mechanism. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Anaemia and haemoglobin in pregnancy Limitations: A narrative review, not a systematic one. The authors say the role of riboflavin is under-investigated. The abstract gives no trial details. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Fishman 2000 The role of vitamins in the prevention and control of anaemia. Public Health Nutr · PMID 10948381 · DOI |
Systematic review |
People in vitamin supplementation trials that measured anaemia or iron status | Several vitamins; for riboflavin, trials that gave it with or without iron Riboflavin (vitamin B2) by mouth Not given in the abstract Not given in the abstract · vs Varied |
The authors report that riboflavin enhances the blood-count response to iron and that its deficiency may account for a good share of anaemia in many populations. Overall, they say the public health effect of vitamin supplements on anaemia is not clear, and the interactions between vitamins are not well understood. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Anaemia and iron status Limitations: A 2000 review (searched MEDLINE only). The abstract names no riboflavin trials or numbers. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Glaser 2015 The Association of Dietary Lutein plus Zeaxanthin and B Vitamins with Cataracts in the Age-Related Eye Disease Study: AREDS Report No. 37. Ophthalmology · PMID 25972257 · DOI |
Cohort observational |
3115 3,115 people (6,129 eyes) aged 55 to 80 in the Age-Related Eye Disease Study, followed for a mean of 9.6 years |
Riboflavin eaten in food (from a food questionnaire), not a supplement Riboflavin (vitamin B2) by mouth Highest versus lowest fifth (quintile) of intake Mean follow-up 9.6 years · vs Lowest fifth of intake |
At the start, people in the highest fifth of riboflavin intake had lower odds of mild nuclear cataract (OR 0.78; 0.63 to 0.97), moderate nuclear cataract (OR 0.62; 0.43 to 0.90) and mild cortical cataract (OR 0.80; 0.65 to 0.99) than the lowest fifth. The abstract reports similar results for vitamin B12 and no link for lutein plus zeaxanthin. Highest vs lowest intake: moderate nuclear cataract OR 0.62 (0.43 to 0.90 (moderate nuclear cataract)) Methods, limits and fundingOutcomes: Cataract at the start and new cataracts over time Limitations: Observational: it cannot show that riboflavin caused the difference. Food questionnaires are imperfect. The riboflavin link was reported for the cross-sectional (start) comparison. Many other nutrients were tested at once. Not a trial of supplements. Funding and conflicts: The abstract does not name the funder; the record lists NIH extramural research support. Read: abstract |
| Missaglia 2021 ETF dehydrogenase advances in molecular genetics and impact on treatment. Crit Rev Biochem Mol Biol · PMID 33823724 · DOI |
Narrative review |
Patients with riboflavin-responsive MADD (including 5 described in detail) and lab studies of cells | Riboflavin, L-carnitine and/or coenzyme Q10 supplements and a low-fat, low-protein diet in a rare inherited disease Riboflavin (vitamin B2) by mouth Not given in the abstract Not given in the abstract |
The review outlines the symptoms linked to ETF-QO deficiency, which is often tied to riboflavin-responsive MADD, and the benefits reported with riboflavin, L-carnitine, coenzyme Q10 and a diet low in fat and protein. It links the type of gene change to how severe the disease is. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Gene changes (ETFDH) and the benefits of treatments Limitations: A narrative review of a rare disease; the abstract gives no trial numbers. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Rooney 2020 Impact of the MTHFR C677T polymorphism on one-carbon metabolites: Evidence from a randomised trial of riboflavin supplementation. Biochimie · PMID 32330571 · DOI |
Randomized trial |
115 115 adults screened for MTHFR genotype (blood samples from earlier trials); 47 adults with the TT genotype in the supplement part |
Riboflavin (vitamin B2) supplement Riboflavin (vitamin B2) by mouth 1.6 mg a day 16 weeks · vs Placebo (24 on riboflavin, 23 on placebo) |
Adults with the TT genotype had lower SAM (74.7 vs 85.2 nmol/L; p = 0.013) and a lower SAM:SAH ratio (p = 0.043), and higher homocysteine (p = 0.043), than adults with the CC genotype. Riboflavin raised SAM (p = 0.008) and cystathionine (p = 0.045); other measured chemicals did not respond. SAM and cystathionine rose with riboflavin in TT adults (Not given in the abstract) Methods, limits and fundingOutcomes: Blood levels of body chemicals linked to folate and homocysteine (one-carbon metabolism) Limitations: Small groups. Blood chemistry, not health outcomes. Samples came from earlier blood pressure trials. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Schoenen 1998 Effectiveness of high-dose riboflavin in migraine prophylaxis. A randomized controlled trial. Neurology · PMID 9484373 · DOI |
Randomized trial |
55 55 patients with migraine |
Riboflavin (vitamin B2) supplement Riboflavin (vitamin B2) by mouth 400 mg a day 3 months · vs Placebo |
Riboflavin was better than placebo at lowering attack frequency (p = 0.005) and headache days (p = 0.012). At least half fewer headache days ('responders'): 15% on placebo and 59% on riboflavin (p = 0.002); number needed to treat 2.3. Three minor side effects: diarrhoea and frequent urination (polyuria) in the riboflavin group, stomach cramps in the placebo group. None was serious. Responders 59% vs 15% (p = 0.002) (Not given in the abstract) Methods, limits and fundingOutcomes: Attack frequency, headache days, share of patients who improved by at least half Limitations: Only 55 people and 3 months. One trial; later trials gave mixed sizes of effect (see the 2022 pooled analysis). Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Talandashti 2025 Effects of selected dietary supplements on migraine prophylaxis: A systematic review and dose-response meta-analysis of randomized controlled trials. Neurol Sci · PMID 39404918 · DOI |
Meta-analysis |
People with migraine in 22 randomised trials of several supplements (riboflavin was one of them) | Riboflavin among several supplements (magnesium, CoQ10, alpha-lipoic acid, probiotics, vitamin D, omega-3) Riboflavin (vitamin B2) by mouth Not given in the abstract for riboflavin Not given in the abstract · vs Placebo |
Riboflavin decreased attack frequency (mean difference -1.34 attacks). The authors report that, in adults, these supplements did not significantly change the other outcomes, and that they graded certainty with GRADE, but the abstract does not give the grade for riboflavin. Attack frequency: mean difference -1.34 (Not given in the abstract) Methods, limits and fundingOutcomes: Number of attacks, duration, severity and monthly migraine days Limitations: The abstract does not say how many trials were of riboflavin or give its certainty rating. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Watson-Fargie 2025 Late-onset multiple-acyl-CoA-dehydrogenase deficiency-like condition: a case series from the West of Scotland. Neuromuscul Disord · PMID 40157166 · DOI |
Case series |
19 19 adults with a muscle disorder that looked like late-onset MADD (median age at onset 52) |
Riboflavin therapy together with nutrition advice and advice to stop sertraline Riboflavin (vitamin B2) by mouth Not given in the abstract Not given in the abstract |
All 19 had abnormal acylcarnitine profiles and abnormal muscle biopsies. 16 of 19 were taking sertraline and 14 of 19 had a trigger before illness. Only 4 of 19 carried one likely pathogenic ETFDH variant. All showed variable improvement after riboflavin, nutrition advice and advice to stop sertraline. The authors suggest this late-onset form is more often acquired than genetic. All 19 improved to a variable degree (Not applicable) Methods, limits and fundingOutcomes: Muscle weakness and damage, lab and biopsy findings, improvement Limitations: No control group, and three things were changed at once (riboflavin, diet, stopping sertraline), so the part played by riboflavin cannot be separated out. Funding and conflicts: The authors declare no competing financial interests (stated in the record). Read: abstract |
| Wilson 2012 Riboflavin offers a targeted strategy for managing hypertension in patients with the MTHFR 677TT genotype: a 4-y follow-up. Am J Clin Nutr · PMID 22277556 · DOI |
Randomized crossover trial |
83 83 patients with cardiovascular disease (all three MTHFR genotypes) followed up; 31 with the TT genotype took part in the crossover |
Riboflavin (vitamin B2) supplement Riboflavin (vitamin B2) by mouth 1.6 mg a day 16 weeks · vs Placebo (groups swapped after the first treatment period) |
People with the TT genotype had higher systolic blood pressure than the others. Riboflavin lowered systolic blood pressure by 9.2 mm Hg (SD 12.8; p = 0.001) and diastolic by 6.0 mm Hg (SD 9.9; p = 0.003) in the TT group. Systolic -9.2 mm Hg, diastolic -6.0 mm Hg in TT genotype (Not given in the abstract) Methods, limits and fundingOutcomes: Blood pressure Limitations: Only 31 people with the TT genotype. The same research group ran the earlier trial. Confined to patients with cardiovascular disease. The authors say the findings need confirming in the general population. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Yildiz 2019 Determinants of Riboflavin Responsiveness in Multiple Acyl-CoA Dehydrogenase Deficiency. Pediatr Neurol · PMID 31331668 · DOI |
Case series |
25 25 patients at one hospital with the rare inherited condition MADD (multiple acyl-CoA dehydrogenase deficiency) |
Riboflavin treatment for a rare inherited metabolic disease (care under specialist doctors) Riboflavin (vitamin B2) by mouth Not given in the abstract Not given in the abstract · vs Responsive vs unresponsive patients compared |
Patients who responded to riboflavin had favourable outcomes but could still have life-threatening complications. They were diagnosed later (median two years versus 30 days). Patients who did not respond more often had breathing trouble and lowered consciousness and presented younger. Lab profiles could not tell the two groups apart. The authors write that treatment is available for the riboflavin-responsive form. No effect size; descriptive (Not applicable) Methods, limits and fundingOutcomes: Symptoms, outcomes and lab profiles Limitations: Retrospective hospital records from one centre; no comparison group given placebo. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| s-medlineplus-riboflavin MedlinePlus Medical Encyclopedia: Riboflavin · Source |
Health agency n/a |
Methods, limits and fundingRead: full-text | ||
| s-nhs-vitamin-b NHS: B vitamins and folic acid (riboflavin section) · Source |
Health agency n/a |
Methods, limits and fundingRead: full-text | ||
| s-ods-riboflavin NIH Office of Dietary Supplements: Riboflavin fact sheet for health professionals · Source |
Health agency n/a |
Methods, limits and fundingRead: not-read | ||
| s-usda-fdc-168462 USDA FoodData Central: Spinach, raw · Source |
Food database n/a |
Methods, limits and fundingRead: saved-data | ||
| s-usda-fdc-170567 USDA FoodData Central: Nuts, almonds · Source |
Food database n/a |
Methods, limits and fundingRead: saved-data | ||
| s-usda-fdc-170886 USDA FoodData Central: Yogurt, plain, low fat · Source |
Food database n/a |
Methods, limits and fundingRead: saved-data | ||
| s-usda-fdc-171265 USDA FoodData Central: Milk, whole, 3.25% milkfat, with added vitamin D · Source |
Food database n/a |
Methods, limits and fundingRead: saved-data | ||
| s-usda-fdc-173414 USDA FoodData Central: Cheese, cheddar · Source |
Food database n/a |
Methods, limits and fundingRead: saved-data |
What we do not know yet
- No trial read compares riboflavin with a standard migraine drug, and the pooled analyses give no GRADE rating for riboflavin in their abstracts.
- The blood pressure trials come from one research group and cover only people with the MTHFR 677TT variant.
- No trial of riboflavin supplements for cataract, energy or tiredness in people who are not short of it was found.
- No source read gives long-term safety data for high-dose riboflavin, or says whether it is safe in pregnancy, breastfeeding or children.
- The NIH Office of Dietary Supplements fact sheet could not be opened, so medicine interactions and any upper limit from it were not checked.
- MADD evidence is case series and reviews only. The history of riboflavin was not researched.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 5
Migraine attack frequency and headache days
Lowered in trials
How often migraine attacks happen and on how many days a month or trial period the person has a headache.
Low certaintyResults and what it means
Why it was measured
It is the usual way migraine prevention trials measure whether a treatment helps.
Statistical vs. clinical meaning
Lower in several trials but with large differences between trials.
Safety implication
Minor stomach and urine effects reported in one trial.
| Study | Result | People | Product |
|---|---|---|---|
| 7 | Fewer attacks (p = 0.005) and fewer headache days (p = 0.012) than placebo; 59% vs 15% had at least half fewer headache days. | 55 patients with migraine | Riboflavin supplement vs placebo for 3 months |
| 1 | Pooled analysis: migraine days p = 0.005, frequency p = 0.001, duration p = 0.003, pain score p = 0.015. | 673 people in 9 trials | Riboflavin supplements vs control, about 3 months |
| 8 | Attack frequency lower by 1.34 attacks (mean difference). | Adults with migraine in randomised trials | Riboflavin supplements vs placebo |
Haemoglobin and anaemia
Raised in trials
Haemoglobin is the protein in red blood cells that carries oxygen. Anaemia means too little of it.
Low certaintyResults and what it means
Why it was measured
Low riboflavin may reduce the body's ability to use iron to make red blood cells.
Statistical vs. clinical meaning
Suggests low riboflavin can be one cause of anaemia and that correcting it may help in those people.
Safety implication
Anaemia needs a doctor's check; riboflavin is not shown to treat anaemia from other causes.
| Study | Result | People | Product |
|---|---|---|---|
| 3 | Riboflavin enhances the blood-count response to iron (no numbers in the abstract). | People in vitamin trials measuring anaemia or iron status | Riboflavin with or without iron |
| 2 | Randomised trials in pregnant women from low- and middle-income countries showed benefits on haematological status and anaemia (no numbers in the abstract). | Pregnant women | Riboflavin supplements |
Blood pressure (systolic and diastolic)
Lowered in trials
The pressure of blood in the arteries: the top number (systolic) and bottom number (diastolic), measured in mm Hg.
Low certaintyResults and what it means
Why it was measured
High blood pressure is a risk factor for heart disease and stroke.
Statistical vs. clinical meaning
A sizeable fall in one small group. The result has not been shown for people without this gene variant.
Safety implication
Do not change blood pressure medicine without a doctor.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | In patients with the MTHFR 677TT variant, riboflavin lowered systolic by 9.2 mm Hg (p = 0.001) and diastolic by 6.0 mm Hg (p = 0.003). | 31 TT patients with cardiovascular disease (83 followed up) | Riboflavin vs placebo, 16 weeks, crossover |
SAM and cystathionine (folate-related blood chemicals)
Raised in trials
SAM (S-adenosylmethionine) is a methyl donor made by the body; cystathionine is a by-product of homocysteine handling. Both reflect how folate-related chemistry (one-carbon metabolism) is working.
Low certaintyResults and what it means
Why it was measured
Used to see whether riboflavin changes the chemistry linked to the MTHFR enzyme.
Statistical vs. clinical meaning
A sign that riboflavin affects the relevant chemistry in this gene group.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 6 | In adults with the TT variant, riboflavin raised SAM (p = 0.008) and cystathionine (p = 0.045). TT adults had lower SAM (74.7 vs 85.2 nmol/L, p = 0.013) than CC adults before treatment. | 47 TT adults in the supplement part (115 adults in all) | Riboflavin vs placebo, 16 weeks |
Lens opacity (cataract grade)
Lowered (observational) in trials
How cloudy the lens of the eye is on a standard photograph grading scale.
Very low certaintyResults and what it means
Why it was measured
Cataract is a main cause of vision loss in older adults.
Statistical vs. clinical meaning
A link in food intake, not a result of supplements and not proof of cause.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 4 | Highest vs lowest fifth of dietary riboflavin intake: moderate nuclear cataract OR 0.62 (0.43 to 0.90). | 3,115 people aged 55 to 80 in AREDS | Riboflavin from food (questionnaire), observational |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 5
- Riboflavin has a very good safety record at food levels. MedlinePlus says riboflavin is water soluble, leftover amounts leave the body in the urine, and 'there is no known poisoning from riboflavin'. The NHS says you should be able to get all you need from a varied diet. Authoritative guidance 12 13
- High-dose supplements: the evidence is thin. The NHS says there is not enough evidence to know the effects of taking high daily doses of riboflavin supplements. Its page also says that too much might be harmful and that the Department of Health and Social Care advises that 40 mg or less a day of supplements is unlikely to cause harm. That is the UK agency's statement, not advice to take any amount. Migraine trials gave much more than this (see the studies table) and reported only minor effects in one trial, but trials are small and short. Talk to a doctor or pharmacist before using a high-dose supplement. Authoritative guidance 13 7
- Pregnancy and breastfeeding. Official reference intakes are higher in pregnancy and breastfeeding (US: 1.4 mg and 1.6 mg a day, MedlinePlus), and a 2026 review says mild riboflavin shortage is common in pregnancy, even in high-income countries. We did not read a source that says high-dose riboflavin supplements are safe or unsafe in pregnancy or breastfeeding. Ask your midwife, doctor or pharmacist before using supplements. Authoritative guidance 12 2
- Children. MedlinePlus lists lower reference intakes for babies and children by age. We found no source that describes the safety of riboflavin supplements in children, and trials of migraine in children are not covered on this page. Ask a paediatrician or pharmacist. Authoritative guidance 12
- Light destroys riboflavin. MedlinePlus and the NHS both say light, including UV light, destroys riboflavin, so foods that contain it should not be stored in clear containers in direct sunlight. Authoritative guidance 12 13
Side effects 2
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Diarrhoea and frequent urination (polyuria) in a migraine trial of high-dose riboflavin One small trial of about 3 months. It does not rule out other effects in larger or longer use. | 2 of the riboflavin group in a 55-person trial (one placebo patient had stomach cramps). Exact group sizes are not in the abstract. | minor; none was serious Not described in the abstract. | Randomized trial 7 |
| No known poisoning from riboflavin This is an agency summary, not a systematic safety review. | Not applicable: a statement from MedlinePlus (reviewed 1/21/2025). | not applicable Not applicable. | Authoritative guidance 12 |
Liver
No liver injury from riboflavin was found in the sources read. A liver-safety source such as LiverTox was not searched.
How often. No frequency was found.
Monitoring. No agency monitoring advice was found.
This is a safety connection. It is not evidence that Vitamin B2 (riboflavin) supports liver health.
Medicines and supplements 4
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Iron supplement | Riboflavin helper molecules are needed to release iron from storage for making red blood cells. | A 2000 review reports that riboflavin enhances the blood-count response to iron. This is a helpful partnership in people who are short of both, not a hazard. | Human trial review Low certainty 3 2 | If you take iron for anaemia, ask a doctor about testing the cause before adding other supplements. |
| Other B vitamins supplement | MedlinePlus says riboflavin works with the other B vitamins. | Not described in terms of harm. Many multivitamin and B-complex products contain several B vitamins, so total intake can add up. | Authoritative guidance Not enough evidence 12 | Ask a pharmacist to check the total in all the supplements you take. |
| Medicines of any kind prescription | Not known. The NIH Office of Dietary Supplements fact sheet normally lists medicine interactions, but it could not be opened. | No interaction with a medicine is stated on this page because no source we could read lists one. That is a gap in what we checked, not proof that there are none. | Not checked Not enough evidence 14 | Ask your doctor or pharmacist whether riboflavin suits your medicines. |
| Sertraline (an antidepressant) in a rare muscle disorder prescription | Not known. In a Scottish series of 19 adults with a MADD-like muscle disorder, 16 were taking sertraline; the authors suggest acquired factors may be involved. | This is a case series without a control group. It does not show that sertraline causes the disorder or that it interacts with riboflavin. | Case series Very low certainty 9 | Never stop a prescribed medicine on your own. Talk to your prescriber about any new muscle weakness or pain. |
Who should check first 2
| Situation | Advice | Evidence |
|---|---|---|
| Rare inherited riboflavin-related disorders (such as MADD) | Treatment is directed by specialist doctors with lab testing. Do not try to treat it yourself. | Case series 11 5 |
| A known allergy or reaction to a riboflavin supplement or one of its other ingredients | Stop and speak to a doctor or pharmacist. Supplements contain other ingredients that can cause reactions. | General safety statement |
Overdose, product quality and regulators
Summary. MedlinePlus knows of no poisoning from riboflavin. The NHS says there is not enough evidence about the effects of high daily doses.
Animal. Not reviewed.
High dose or long term signals. Only minor diarrhoea and frequent urination in one small 3-month trial. No long-term safety study of high-dose riboflavin was read.
Overdose response. Not found.
Genotoxicity. Not researched.
We read no source about contaminants or whether supplement labels match what is inside.
Light damage to riboflavin in foods. MedlinePlus and the NHS say light destroys riboflavin, so foods that contain it, such as milk, should be stored away from direct light. 12 13
| Body | Action | Date |
|---|---|---|
| NHS (UK) (United Kingdom) | Adults aged 19 to 64 need about 1.3 mg a day (men) and 1.1 mg a day (women), which a varied diet should supply. Not enough evidence to know the effects of high daily doses of supplements; the Department of Health and Social Care advice is that 40 mg or less a day of supplements is unlikely to cause harm. source | 2020-08-03 |
| MedlinePlus (US National Library of Medicine) (United States) | No known poisoning from riboflavin. US Recommended Dietary Allowances: males 14 and older 1.3 mg a day; females 14 to 18 years 1.0 mg; females 19 and older 1.1 mg; pregnancy 1.4 mg; breastfeeding 1.6 mg. Reference intakes are for planning the diets of healthy people. source | 2025-01-21 |
When to get medical help
- Swelling of the face, lips or throat, or trouble breathing, after any supplement: call your local emergency number (911 in the US, 999 in the UK). This is general allergy guidance, not specific to riboflavin.
- A sudden, severe or new kind of headache needs urgent medical care. Do not rely on a vitamin. This is general medical safety advice.
- Mouth or lip sores, a sore throat, skin problems or tiredness that do not go away can be signs of a vitamin shortage or of other illness. See a doctor (MedlinePlus lists them among signs of severe deficiency).
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is riboflavin?
What foods contain riboflavin?
What happens if I do not get enough riboflavin?
A severe shortage can cause anaemia, mouth or lip sores, skin problems, a sore throat and swollen mucous membranes. It is not common in the US because the vitamin is plentiful in food. See a doctor if you have these signs.
Can riboflavin prevent migraines?
Does riboflavin give you more energy?
Can riboflavin help with anaemia?
Does riboflavin lower blood pressure?
Is it possible to take too much riboflavin?
Are there side effects?
Is riboflavin safe in pregnancy or breastfeeding?
Does light affect riboflavin in food?
Does eating more riboflavin protect the eyes?
In a large eye study, people who ate the most riboflavin had lower odds of cataract, but this is an observational link and does not prove cause. We found no supplement trial for cataract.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-26
- Last substantive update
- 2026-10-26
- How we research
- We started from our existing riboflavin summary, read the MedlinePlus and NHS pages in full, used saved USDA FoodData Central data for food amounts and re-read PubMed abstracts for the trials and reviews. Only abstracts were read for studies. The NIH Office of Dietary Supplements page could not be opened. Items we could not verify are flagged in the research gaps.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. Funders are not stated in most of the abstracts we read; where a source did not say, we say so.
Sources 19
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Chen YS, Lee HF, Tsai CH, Hsu YY, Fang CJ, Chen CJ, et al.. Effect of Vitamin B2 supplementation on migraine prophylaxis: a systematic review and meta-analysis.. Nutr Neurosci. 2022. PMID 33779525. DOI 10.1080/1028415X.2021.1904542. (abstract)
- Duffy B, McNulty H, Ward M, Pentieva K. Anaemia during pregnancy: could riboflavin deficiency be implicated?. Proc Nutr Soc. 2026. PMID 39540254. DOI 10.1017/S0029665124007468. (abstract)
- Fishman SM, Christian P, West KP. The role of vitamins in the prevention and control of anaemia.. Public Health Nutr. 2000. PMID 10948381. DOI 10.1017/s1368980000000173. (abstract)
- Glaser TS, Doss LE, Shih G, Nigam D, Sperduto RD, Ferris FL, et al.. The Association of Dietary Lutein plus Zeaxanthin and B Vitamins with Cataracts in the Age-Related Eye Disease Study: AREDS Report No. 37.. Ophthalmology. 2015. PMID 25972257. DOI 10.1016/j.ophtha.2015.04.007. (abstract)
- Missaglia S, Tavian D, Angelini C. ETF dehydrogenase advances in molecular genetics and impact on treatment.. Crit Rev Biochem Mol Biol. 2021. PMID 33823724. DOI 10.1080/10409238.2021.1908952. (abstract)
- Rooney M, Bottiglieri T, Wasek-Patterson B, McMahon A, Hughes CF, McCann A, et al.. Impact of the MTHFR C677T polymorphism on one-carbon metabolites: Evidence from a randomised trial of riboflavin supplementation.. Biochimie. 2020. PMID 32330571. DOI 10.1016/j.biochi.2020.04.004. (abstract)
- Schoenen J, Jacquy J, Lenaerts M. Effectiveness of high-dose riboflavin in migraine prophylaxis. A randomized controlled trial.. Neurology. 1998. PMID 9484373. DOI 10.1212/wnl.50.2.466. (abstract)
- Talandashti MK, Shahinfar H, Delgarm P, Jazayeri S. Effects of selected dietary supplements on migraine prophylaxis: A systematic review and dose-response meta-analysis of randomized controlled trials.. Neurol Sci. 2025. PMID 39404918. DOI 10.1007/s10072-024-07794-0. (abstract)
- Watson-Fargie T, Coomber A, Edwards R, Barr M, Brennan K, Fletcher E, et al.. Late-onset multiple-acyl-CoA-dehydrogenase deficiency-like condition: a case series from the West of Scotland.. Neuromuscul Disord. 2025. PMID 40157166. DOI 10.1016/j.nmd.2025.105343. (abstract)
- Wilson CP, Ward M, McNulty H, Strain JJ, Trouton TG, Horigan G, et al.. Riboflavin offers a targeted strategy for managing hypertension in patients with the MTHFR 677TT genotype: a 4-y follow-up.. Am J Clin Nutr. 2012. PMID 22277556. DOI 10.3945/ajcn.111.026245. (abstract)
- Yildiz Y, Talim B, Haliloglu G, Topaloglu H, Akcoren Z, Dursun A, et al.. Determinants of Riboflavin Responsiveness in Multiple Acyl-CoA Dehydrogenase Deficiency.. Pediatr Neurol. 2019. PMID 31331668. DOI 10.1016/j.pediatrneurol.2019.06.015. (abstract)
- . MedlinePlus Medical Encyclopedia: Riboflavin. . . (full-text)
- . NHS: B vitamins and folic acid (riboflavin section). . . (full-text)
- . NIH Office of Dietary Supplements: Riboflavin fact sheet for health professionals. . . (not-read)
- . USDA FoodData Central: Spinach, raw. . . (saved-data)
- . USDA FoodData Central: Nuts, almonds. . . (saved-data)
- . USDA FoodData Central: Yogurt, plain, low fat. . . (saved-data)
- . USDA FoodData Central: Milk, whole, 3.25% milkfat, with added vitamin D. . . (saved-data)
- . USDA FoodData Central: Cheese, cheddar. . . (saved-data)
Where to buy
Check the label first. Whatever you buy, look for these:
- The amount of the active ingredient per serving, not just the front-label claim
- A third-party testing mark (USP, NSF or ConsumerLab)
- Other ingredients and allergens
- Ask a pharmacist about interactions with your medicines
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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