Riboflavin (Vitamin B2): Roles, Food Sources, Deficiency and Safety
Riboflavin (vitamin B2): what it does, food sources and light sensitivity, official intake levels, signs of deficiency, what migraine trials found, and safety questions.
Content last updated . This page has not been medically reviewed.
What is Vitamin B2 good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Releasing energy from food
Established roleRiboflavin helps the body release energy from carbohydrates, proteins and fats.
Supplements: Supplements correct a shortfall; no good evidence of extra benefit when intake is adequate. We found no good evidence that extra riboflavin raises energy in people who are not deficient.
Mitochondrial energy helper
Established roleRiboflavin acts as a helper (cofactor) for the energy machinery inside cells, the mitochondria.
Supplements: The cofactor role is established; using supplements to treat brain or nerve disease is not proven.
Healthy skin
Established roleThe NHS says riboflavin helps keep skin healthy.
Supplements: Supplements correct a shortfall; no good evidence of extra benefit when intake is adequate.
Healthy eyes
Established roleThe NHS says riboflavin helps keep the eyes healthy.
Supplements: Supplements correct a shortfall; no good evidence of extra benefit when intake is adequate. Evidence for preventing eye disease is not established.
Healthy nervous system
Established roleThe NHS says riboflavin helps keep the nervous system healthy.
Supplements: Supplements correct a shortfall; no good evidence of extra benefit when intake is adequate.
Red blood cell production
Deficiency linkMedlinePlus says riboflavin helps with red blood cell production.
Supplements: Correcting a shortfall may help anemia caused by deficiency; it is not a treatment for other kinds of anemia.
Body growth
Established roleMedlinePlus says riboflavin is important for body growth.
Supplements: Supplements correct a shortfall; no good evidence of extra benefit when intake is adequate.
Working with other B vitamins
Established roleRiboflavin works together with the other B vitamins.
Supplements: Needed as part of an adequate diet; not shown to add benefit on its own when intake is adequate.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Health goals (2)
- Energy BoostEstablished role
Riboflavin helps release energy from food. In people who are not deficient, we found no good evidence that extra riboflavin increases energy.
- Healthy SkinEstablished role
The NHS says riboflavin helps keep skin healthy, and skin complaints are a sign of severe deficiency. Extra amounts are not shown to improve skin in people who get enough.
Body systems (4)
- Energy & FatigueEstablished role
Riboflavin is needed to release energy from food. Extra amounts are not shown to reduce tiredness when intake is adequate.
- Integumentary SystemEstablished role
The NHS says riboflavin helps keep skin healthy; skin complaints can occur in severe deficiency.
- Nervous SystemEstablished role
The NHS says riboflavin helps keep the nervous system healthy.
- Skin, Hair & BeautyEstablished role
Riboflavin helps keep skin healthy (NHS). We found no source on hair, and no proof that supplements improve skin when intake is adequate.
Body parts (4)
- EyesEstablished role
The NHS says riboflavin helps keep the eyes healthy.
- MitochondriaEstablished role
Riboflavin acts as a cofactor in the mitochondria, the energy-producing parts of cells.
- Nervous SystemEstablished role
The NHS says riboflavin helps keep the nervous system healthy.
- SkinEstablished role
The NHS says riboflavin helps keep skin healthy.
Functional actions (3)
- Energy ProductionEstablished role
Riboflavin helps release energy from carbohydrates, proteins and fats. This role does not mean extra supplements raise energy.
- Mitochondrial SupportEstablished role
Riboflavin is an essential cofactor in the mitochondria. Benefits of supplements for mitochondrial or brain disease are not established.
- Nervous System SupportEstablished role
The NHS says riboflavin helps keep the nervous system healthy.
Root causes (1)
- Nutrient DeficiencyDeficiency link
Not getting enough riboflavin causes deficiency, which can include anemia, mouth or lip sores and skin complaints. It is uncommon in the United States.
Habits (1)
- Balanced NutritionEstablished role
MedlinePlus advises getting vitamins from a balanced diet with a variety of foods; the NHS says most people can meet their needs this way.
Conditions & symptoms (4)
- Riboflavin DeficiencyDeficiency link
Not enough riboflavin causes deficiency. It is uncommon in the United States because the vitamin is plentiful in food.
- AnemiaDeficiency link
Severe riboflavin deficiency can include anemia. An expert 2026 review rates the evidence for riboflavin in nutritional anemia as moderate.
- Migraine DisordersPreliminary or mixed
In trials, 400 mg a day for three months reduced migraine attacks in adults, but results varied and evidence is limited. This is a study amount, not advice, and migraine needs a clinician.
- Sore ThroatDeficiency link
Sore throat is listed among signs of severe deficiency. It has many other causes and cannot diagnose deficiency.
Overview
Riboflavin is vitamin B2. The NHS says it helps keep skin, eyes and the nervous system healthy and helps the body release energy from food. [1] MedlinePlus says it works with the other B vitamins, is important for body growth, helps red blood cell production and helps release energy from carbohydrates, proteins and fats. [2] It is water soluble and not stored in the body in large amounts, so a regular supply is needed. [2]Evidence labels used here: established nutritional role / deficiency treatment, promising but limited, mixed, insufficient evidence and marketing claim. "Proper evidence not found" means we searched the places named and found nothing usable.
Food sources and light
The NHS lists milk, eggs, fortified breakfast cereals, mushrooms and plain yoghurt. [1] MedlinePlus adds green leafy vegetables, lean meats, organ meats such as liver and kidneys, legumes and nuts, and says breads and cereals are often fortified. [2]Both sources say light destroys riboflavin: the NHS advises keeping these foods out of direct sunlight, and MedlinePlus advises against storing riboflavin-containing foods in clear containers exposed to light. [1][2] For lists by food see foods high in biotin, thiamin, riboflavin, niacin, B6 and pantothenic acid.
Official intake levels
These are published levels for the groups named, not personal advice. See RDA, AI, DV and UL for what the terms mean.| Body, country and year | Group | Level for riboflavin |
|---|---|---|
| NHS, UK, page reviewed 2020 | Adults 19 to 64, men / women | About 1.3 mg / 1.1 mg a day [1] |
| US Dietary Reference Intakes, as listed by MedlinePlus (review 2025) | Males 14 and older / females 19 and older | RDA 1.3 mg / 1.1 mg a day; 1.4 mg in pregnancy; 1.6 mg in lactation [2] |
| Health Canada, table dated 2025 | Adults 19 to 30, males / females | RDA 1.3 mg / 1.1 mg a day; no upper level set because data are insufficient [3] |
| EFSA, EU, overview version 2025 | All groups | No adequate data to derive a tolerable upper level [4] |
| Daily Value on US labels (FDA, 2024) | Label reference only | 1.3 mg [5] |
Deficiency
Established. MedlinePlus says lack of riboflavin is not common in the United States because the vitamin is plentiful in the food supply. Symptoms of severe deficiency include anemia, mouth or lip sores, skin complaints, sore throat and swelling of mucous membranes. [2] Those symptoms overlap with many other conditions, so they cannot diagnose deficiency. If you are worried, see a clinician rather than self-treating. See vitamin deficiency symptoms.Proper evidence not found on how common deficiency is in specific groups: we read the NHS and MedlinePlus pages, and NIH Office of Dietary Supplements pages were blocked to us.
What research shows for specific uses
| Question | What the source found | Label |
|---|---|---|
| Migraine prevention in adults | A 2022 meta-analysis of 8 randomized trials and 1 controlled trial (673 people) found 400 mg a day for three months reduced migraine days, duration, frequency and pain score, but results varied a lot between trials. [6] | Promising but limited, mixed |
| Migraine, compared with other supplements | A 2025 dose-response meta-analysis of 22 trials found riboflavin lowered attack frequency (mean difference -1.34), and called for higher-quality trials. [7] | Promising but limited |
| Energy, skin or eye health in people who are not deficient | Proper evidence not found. We read the NHS and MedlinePlus pages and searched PubMed for riboflavin and migraine reviews; no usable trial results for these uses turned up. | Marketing claim |
The 400 mg figure is an amount used in studies, not a recommendation. It is far above the intake levels in the table. Migraine is a medical condition that needs a clinician's assessment. See riboflavin and migraine for more detail.
Safety and precautions
- Upper limits: the NHS says there is not enough evidence about high-dose supplements and that 40 mg or less a day is unlikely to cause harm (UK advice). [1] MedlinePlus says there is no known poisoning from riboflavin, since leftover amounts leave the body in urine (US). [2]
- Medicines: Proper evidence not found in the pages we could read. Check medication interactions and ask a pharmacist.
- Pregnancy and breastfeeding: the US RDA is higher (1.4 mg and 1.6 mg). [2] Discuss supplements with your midwife, doctor or pharmacist.
- Children: needs rise with age (US RDA 0.5 mg at 1 to 3 years to 1.3 mg for males 14 and older). [2] See vitamins for children and teenagers.
- Kidney and liver conditions, and surgery: Proper evidence not found specific to riboflavin. A 2023 review notes water-soluble vitamin needs change in kidney disease and should be managed by the care team. [8] See vitamins and kidney or liver disease and vitamins before surgery.
- Quality: see quality testing and certifications.
Testing
Proper evidence not found: none of the pages we read describe a routine riboflavin blood test. Deficiency is not diagnosed from symptoms alone; see deficiency testing and its limits.Related
All vitamins · Understanding vitamins · B-complex productsFrequently asked questions
What foods are high in riboflavin?
Milk, eggs, yoghurt, mushrooms, fortified cereals, organ meats, legumes and nuts, per the NHS and MedlinePlus. [1][2]
Does light destroy riboflavin?
Yes. Both the NHS and MedlinePlus say light destroys it, so keep riboflavin-rich foods out of direct sunlight. [1][2]
Is riboflavin good for migraine?
Some trials suggest a reduction in attacks at study amounts, but results vary and the evidence is limited. Ask a clinician. [6][7]
Can you take too much riboflavin?
No poisoning is known in the US source, but the NHS says evidence on high doses is not enough. [2][1]
Is riboflavin deficiency common?
MedlinePlus says it is not common in the United States. [2]
References
- NHS (UK). B vitamins and folic acid. Page last reviewed 3 August 2020. Read 2026-10-23.
- MedlinePlus Medical Encyclopedia (US National Library of Medicine). Riboflavin. Review date 1/21/2025. Read 2026-10-23.
- Health Canada. Dietary reference intakes tables: Reference values for vitamins. Page dated 2025-11-19. Read 2026-10-23 through a web-fetch tool, which returned the tables as a text summary; direct download was blocked.
- European Food Safety Authority. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA NDA Panel, version 1, August 2025. Read 2026-10-23 (text extracted from the PDF; table layout reconstructed).
- US Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. Content current as of 03/05/2024. Read 2026-10-23.
- Chen YS, Lee HF, Tsai CH, et al. Effect of vitamin B2 supplementation on migraine prophylaxis: a systematic review and meta-analysis. Nutr Neurosci 2022;25(9):1801-1812. Read 2026-10-23.
- 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;46(2):651-670. Read 2026-10-23.
- Kędzierska-Kapuza K, Szczuko U, Stolińska H, et al. Demand for water-soluble vitamins in a group of patients with CKD versus interventions and supplementation: a systematic review. Nutrients 2023;15(4):860. Read 2026-10-23.