Vitamin B2 (riboflavin):
cracked lips, tiredness and
the MTHFR connection.
Vitamin B2, also called riboflavin, helps your body turn food into energy and keeps your skin, lips and eyes healthy. In one Hyderabad study, half of healthy-looking adults were low in it. Here’s what B2 is used for, the signs of a gap, how much you need, how to increase it naturally, the best Indian foods for it, and why it matters for people with the MTHFR gene variant.
What is vitamin B2? The short answer
What is vitamin B2?
Vitamin B2 (riboflavin) is a B vitamin your body uses to turn food into energy and to keep skin, lips, eyes and blood healthy. The body stores very little, so you need some every day. Milk, curd, eggs and almonds are good sources. Common signs of a gap are cracks at the corners of the mouth, a sore tongue and tiredness.
Vitamin B2 is a bright yellow vitamin found in milk, curd, eggs, almonds and green leafy vegetables. Your body can’t make it and stores very little of it, so it needs a small top-up every day.1 In a study from the National Institute of Nutrition in Hyderabad, half of healthy-looking city adults were low in B2 — the most common vitamin gap the researchers found.2
What vitamin B2 does in your body
What is vitamin B2 used for?
Vitamin B2 is used to turn food into energy. Your body turns it into two helpers called FMN and FAD. These helpers let your cells turn carbohydrates, fats and proteins into energy. B2 also helps your body use vitamin B6, folate and iron, and helps protect cells from damage.
Think of your cells as tiny engines that burn food for fuel. Vitamin B2 is made into two helper molecules, FMN and FAD, which carry energy from one step to the next inside those engines. Without them, the engine still runs, but poorly.1
B2 is also a team player. It helps your body:
- Switch on vitamin B6. The enzyme that makes active B6 needs FMN. People with more B2 tend to have more active B6 in their blood.3
- Use folate. The MTHFR enzyme, which makes active folate, needs FAD to work.4
- Use iron. B2 helps the body absorb and use iron to make healthy red blood cells.4
- Protect cells. An enzyme that recycles the body’s own antioxidant, glutathione, runs on FAD.4
These jobs are recognised in European food law. Riboflavin has approved claims for normal energy-yielding metabolism, the reduction of tiredness and fatigue, normal skin, normal vision, normal red blood cells and normal iron metabolism.5
“B2 rarely works alone. It helps your body use vitamin B6, folate and iron — which is why B vitamins work best as a team.”
Why B2 matters more than its reputation
Signs you may be low in vitamin B2
What are the signs of vitamin B2 deficiency?
The classic signs of low B2 are painful cracks at the corners of the mouth, dry cracked lips, a sore red tongue, a sore throat, itchy red eyes, and flaky skin around the nose. Tiredness is common too. These signs can have other causes, so a doctor’s check is the way to be sure.
The mouth usually shows it first. Skin at the corners of the lips is replaced very quickly, so it is one of the first places to struggle when B2 is short.1,4
Cracks at the corners
Painful splits at the corners of the mouth that keep coming back, and dry, cracked lips.
Sore, red tongue
A swollen, smooth or reddish-purple tongue, sometimes with a sore throat.
Itchy, red, light-shy eyes
Eyes that feel itchy, watery or sore in bright light.
Tiredness and flaky skin
Low energy, plus oily, flaky skin around the nose and mouth.
Low B2 often comes with gaps in other B vitamins and iron, which can cause similar signs. If mouth cracks or tiredness last more than a few weeks, ask your doctor to check. Our guide to the nutrient gaps doctors check for tiredness lists the usual tests.
How common is low vitamin B2 in India?
How common is vitamin B2 deficiency in India?
In a National Institute of Nutrition study of 270 healthy-looking adults in Hyderabad, 50% were low in vitamin B2 on blood tests and 71% ate less B2 than they needed. A recent study of 17 groups in 9 countries found low B2 is common in women and children worldwide.
Scientists at the National Institute of Nutrition (NIN), Hyderabad tested 270 adults aged 30 to 70 who looked and felt healthy. Half of them were low in vitamin B2, and 71% were eating less B2 than they needed. B2 was the most common vitamin gap in the study, ahead of B6 and B12 (46% each).2
India is not alone. A recent study in The Journal of Nutrition looked at 3,567 people in 17 groups across 9 countries and found that low B2 is very common in women and children, in rich and poorer countries alike.6
Three everyday habits explain a lot of the gap:
- Polished grains. In rice and wheat, B2 sits in the outer bran and germ. Polishing rice and refining flour into maida removes much of it.
- Little dairy or eggs. These are the richest everyday sources, so people who eat little of them get less B2.1
- Light. Light breaks down B2, so milk left in sunlight in a clear bottle loses some of it.1
How much B2 per day, and how to increase B2 naturally
How much B2 per day?
ICMR-NIN sets about 2.5 mg a day for moderately active adult men and 2.4 mg for women, a little less if you sit most of the day and more for heavy physical work. The easiest way to increase B2 naturally is a cup or two of milk or curd every day, plus eggs, almonds, whole wheat atta and green leafy vegetables.
India’s targets rise with how active you are, because B2 helps burn the extra fuel.7
| Activity level | Men (per day) | Women (per day) |
|---|---|---|
| Mostly sitting | 2.0 mg | 1.9 mg |
| Moderately active | 2.5 mg | 2.4 mg |
| Heavy physical work | 3.2 mg | 3.1 mg |
How to increase B2 naturally:
- Dairy every day. A cup of curd and a cup of milk give about 1.1 mg, close to half the target.1
- Add an egg and a handful of almonds. Together they add about 0.5 mg.1
- Choose whole grains. Whole wheat atta, brown rice and dals keep the B2 that polishing and refining remove.
- Store milk away from light. Light breaks B2 down.1
- Spread it across the day. The body absorbs only a limited amount at once.1
The MTHFR connection: why B2 matters for folate
What is the link between vitamin B2 and MTHFR?
MTHFR is the enzyme that makes active folate, and it needs FAD, which is made from vitamin B2. In people with two copies of the MTHFR 677 variant (called TT), the enzyme lets go of FAD more easily. Enough B2 helps the enzyme hold on and work normally. In trials, 1.6 mg of B2 a day lowered blood pressure in TT adults.
MTHFR is an enzyme that turns folate from food into its active form. To do this it has to hold on to a helper, FAD, which your body makes from vitamin B2.
About 1 in 10 people in many populations carry two copies of a common MTHFR variant, known as 677TT; in India it is less common, about 1 in 100 in one North Indian sample. Their enzyme is a little “slippery”: it lets go of FAD more easily, so it works less well. Enough B2 helps the enzyme hold on to FAD and work normally again.8
Researchers at Ulster University tested this in people. In adults with the TT variant, just 1.6 mg of B2 a day for 16 weeks lowered systolic blood pressure by about 6 to 13 mmHg. People without the variant saw no change, which shows how personal nutrition can be.8,9
This is why B2 and folate are best thought of together. Our MTHFR and methylfolate guide explains the folate side of the story.
Best Indian foods for vitamin B2
In which foods is vitamin B2 found?
Milk and curd are the best everyday sources of vitamin B2 in Indian diets: one cup gives about 0.5 to 0.6 mg. Eggs, almonds, mushrooms, green leafy vegetables and whole grains add more. Two cups of milk or curd a day cover close to half the daily target.
| Food | Serving | Vitamin B2 (about) |
|---|---|---|
| Curd / yogurt | 1 cup | 0.6 mg |
| Milk | 1 cup | 0.5 mg |
| Almonds | A small handful (28 g) | 0.3 mg |
| Egg | 1 large | 0.2 mg |
| Mushrooms, spinach, methi | 1 serving | Smaller amounts that add up |
| Whole wheat atta, brown rice, dals | Daily staples | More than maida or polished rice |
Simple habits help: have milk, curd, chhaach or paneer daily, choose whole wheat atta over maida, add a handful of almonds, and keep milk out of direct sunlight.1 Your body absorbs only a limited amount of B2 at one time and passes out the extra, so a little every day works better than a lot once a week.1
Energy is teamwork: B vitamins and magnesium.
B2 helps your cells make energy, and magnesium is needed for the same job. Like riboflavin, magnesium has approved claims for normal energy-yielding metabolism and the reduction of tiredness and fatigue.
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Join the waitlist →Nutrient Gap Finder
Answer a few quick questions about your food, routine and symptoms to see which nutrients you may be running low on, and which tests to ask your doctor about.
Try the Nutrient Gap Finder →How to check vitamin B2 on a supplement label
What is the best B2 supplement?
The best B2 supplement names its form and amount clearly. On a label, vitamin B2 appears as “riboflavin” or “riboflavin-5’-phosphate”. Check that B2 is listed, how many milligrams you get per serving, and whether the other B vitamins it works with are there too. Bright yellow urine after taking B2 is normal and harmless.
B2 listed by name
“Riboflavin” or “riboflavin-5’-phosphate”, with the amount in milligrams per serving.
An amount near the daily target
ICMR-NIN sets about 2.5 mg a day for men and 2.4 mg for women.
Its team-mates
B6, folate and B12 alongside B2, since they work together.
“Proprietary blend”
A blend that hides how much B2 you actually get per serving.
Riboflavin-5’-phosphate (also written R5P) is B2 in the same shape as FMN, the helper your body makes from it, and it dissolves in water far more easily than plain riboflavin. Both forms are good sources of vitamin B2.
- The NIN study tested 270 adults in one city, Hyderabad, so it shows how common low B2 can be in urban India; a national B2 survey has not been done.2
- The blood pressure trials were done mainly in Northern Ireland, in adults with the MTHFR 677TT variant who had high blood pressure or heart disease. The effect was seen only in the TT group. B2 is a nutrient, and blood pressure medicines should only be changed with a doctor.8,9
- Migraine trials used 400 mg of B2 a day, far above food and multivitamin amounts. One trial found fewer attacks; two others found no clear benefit over placebo.10
- The gut removes the phosphate from riboflavin-5’-phosphate before absorbing it, and the body then rebuilds FMN and FAD. No human trial has shown that one form raises B2 levels more than the other.1
- The ICMR-NIN targets vary with activity level; the 2.5 and 2.4 mg figures are for moderately active adults.7 Food values are from US food tables and vary with brand and cooking.1 No upper limit has been set for B2, because the body passes out what it does not need.1
- The Indian MTHFR 677TT figure (about 1 in 100) comes from a single North Indian sample; our MTHFR guide covers the data.
- European approved claims describe what a nutrient does in the body at adequate intakes; they are not claims to treat any illness.5
Vitamin B2, answered plainly.
What are the first signs of vitamin B2 deficiency?
How common is vitamin B2 deficiency in India?
Why do the corners of my mouth keep cracking?
What is the link between vitamin B2 and MTHFR?
Which Indian foods are highest in vitamin B2?
How much vitamin B2 do I need each day?
Does vitamin B2 give you energy?
What is riboflavin-5’-phosphate (R5P)?
Why does vitamin B2 turn urine bright yellow?
Does vitamin B2 help with migraines?
What is vitamin B2 used for?
What are the signs of vitamin B2 deficiency?
In which foods is vitamin B2 found?
Which fruit is rich in B2?
What is the best B2 supplement?
Is vitamin B2 the same as B12?
How can I increase my B2 naturally?
How much B2 per day?
Who should not take vitamin B2?
Can I take vitamin B2 every day?
Studies behind this guide
- National Institutes of Health, Office of Dietary Supplements. Riboflavin: Fact Sheet for Health Professionals. ods.od.nih.gov
- Sivaprasad M, Shalini T, Reddy PY, et al. Prevalence of vitamin deficiencies in an apparently healthy urban adult population: assessed by subclinical status and dietary intakes. Nutrition. 2019;63–64:106–113. PMID 30954757 — 270 adults in Hyderabad; 50% low in B2, 71% low dietary intake.
- Jungert A, McNulty H, Hoey L, et al. Riboflavin is an important determinant of vitamin B-6 status in healthy adults. J Nutr. 2020;150(10):2699–2706.
- Linus Pauling Institute, Oregon State University. Riboflavin. Micronutrient Information Center. lpi.oregonstate.edu
- Commission Regulation (EU) No 432/2012: list of permitted health claims made on foods — riboflavin and magnesium entries.
- Riboflavin deficiency is highly prevalent in females and children across high and low/middle income countries worldwide. J Nutr. doi:10.1016/j.tjnut.2025.101277 — 3,567 people, 17 cohorts, 9 countries.
- ICMR-National Institute of Nutrition. Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements, 2020. nin.res.in
- McAuley E, McNulty H, Hughes C, Strain JJ, Ward M. Riboflavin status, MTHFR genotype and blood pressure: current evidence and implications for personalised nutrition. Proc Nutr Soc. 2016;75(3):405–414.
- McNulty H, Strain JJ, Hughes CF, Ward M. Riboflavin, MTHFR genotype and blood pressure: a personalized approach to prevention and treatment of hypertension. Mol Aspects Med. 2017;53:2–9. PMID 27720779
- Schoenen J, Jacquy J, Lenaerts M. Effectiveness of high-dose riboflavin in migraine prophylaxis: a randomized controlled trial. Neurology. 1998;50(2):466–470.