Riboflavin (Vitamin B2)
Riboflavin helps turn food into energy. Deficiency is uncommon in Australia, but it’s worth knowing for people who avoid dairy, and riboflavin has a real (if modest) role in preventing migraine.
Who’s at risk
- People who eat little or no dairy, eggs or meat (some vegans and vegetarians)
- Pregnant or breastfeeding women with low dairy intake
- Heavy alcohol use and poor diet
- Rare inherited riboflavin transporter disorders
Symptoms
- Cracks and sores at the corners of the mouth (angular cheilitis) and sore, cracked lips
- Sore throat and a sore, red mouth
- Itchy, red eyes
- Scaly skin rash, hair loss
- Anaemia if deficiency is long and severe
Cracked mouth corners have many causes, including thrush, dentures and dry skin. Low riboflavin is only one.
Migraine
- In a trial of 55 adults, riboflavin 400 mg a day cut migraine attacks by about 2 a month versus placebo.
- US neurology guidelines rate it “probably effective” for prevention. Canadian guidance suggests 400 mg a day, while noting the evidence is low quality.
- Give it about 3 months to judge. Talk to your GP about it alongside other prevention options.
Food sources
- Milk, yoghurt and cheese, eggs, lean meat, liver, mushrooms, almonds and fortified cereals.
- Adults need about 1.1–1.3 mg a day.
- Light breaks it down, which is one reason milk comes in opaque containers.
Save your money
- Worrying about bright yellow urineThat’s riboflavin being excreted. It’s harmless.
- High-dose B complexes “for energy”They won’t boost energy unless you’re deficient, and some contain high-dose vitamin B6, which can damage nerves.
See your GP if
- Mouth corner cracks or a sore tongue don’t settle in a couple of weeks
- You get frequent migraines and want to discuss prevention
- You follow a restricted diet and want a nutrition check
Common questions
What are the symptoms of riboflavin deficiency?
Cracked mouth corners, sore cracked lips, a sore red mouth and throat, itchy red eyes, scaly skin and hair loss. Severe, long-standing deficiency can cause anaemia.
Does riboflavin help migraine?
Probably, modestly. In one trial, 400 mg a day reduced attacks by about two a month. Give it about three months and discuss it with your GP.
Why does vitamin B2 make urine bright yellow?
Riboflavin is naturally yellow-green and fluorescent. Whatever your body doesn’t need is passed in urine. It’s harmless.
Is too much riboflavin harmful?
No upper limit has been set and no harm has been reported at 400 mg a day for months, because extra is passed in urine.
Helpful resources
- Healthdirect: Vitamins and mineralsPlain-English Australian Government guide. Free.
- Dietitians AustraliaFind an Accredited Practising Dietitian near you.
Evidence and more information
- NIH Office of Dietary Supplements: Riboflavin
- Nutrient Reference Values for Australia and New Zealand (Eat for Health)
maladywise.com/riboflavin/