Riboflavin (Vitamin B2): What It Does and Where to Get It

A rundown of what this everyday B vitamin actually does in the body, and why deficiency is rare but not impossible.

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By the Ration Editorial Team · Reviewed against primary research · Updated July 14, 2026

Riboflavin is a water soluble B vitamin, also known as vitamin B2.

Like other B vitamins, it cannot be stored in large amounts in the body. That means a steady supply from food is needed on a regular basis.

It has a distinctive yellow color, and it is actually what gives riboflavin supplements and B complex vitamins their bright yellow tint in urine after they are excreted.

Riboflavin is converted into two active coenzyme forms, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).

These coenzymes are essential parts of the electron transport chain, the process cells use to turn carbohydrates, fats, and protein into usable energy (ATP).

• Supports energy metabolism from carbohydrates, fats, and protein
• Helps convert other B vitamins, including vitamin B6 and folate, into their active forms
• Acts as an antioxidant cofactor, supporting glutathione recycling
• Supports normal growth, red blood cell production, and healthy vision

Riboflavin is widespread in the food supply, which is a big reason true deficiency is rare in high income countries.

• Organ meats, such as liver
• Dairy products, including milk and yogurt
• Eggs
• Lean meats and fish
• Leafy green vegetables
• Almonds and other nuts
• Fortified breakfast cereals and enriched grains

Riboflavin is best known outside of basic nutrition circles for its potential role in migraine prevention.

The theory is that migraines may be linked to inefficient energy metabolism in brain cells, and since riboflavin is central to cellular energy production, supplementing with it at doses well above the standard daily requirement has been studied as a preventive strategy.

Some small clinical trials have reported fewer migraine days with high dose riboflavin supplementation compared to placebo. However, the overall body of research is limited by small sample sizes, short study durations, and inconsistent results across trials.

Because of this, riboflavin is sometimes mentioned in headache treatment guidelines as a reasonable option to discuss with a doctor, but it is not considered a proven or first line therapy.

Requirements are modest and vary by age, sex, and life stage.

• Adult men generally need slightly more than adult women
• Requirements increase during pregnancy and breastfeeding
• Doses studied for migraine prevention are far higher than typical dietary intake and were used under research or clinical supervision

Because riboflavin is water soluble, excess amounts are generally excreted in urine rather than stored, which is part of why the vitamin has a strong overall safety profile.

Riboflavin deficiency, sometimes called ariboflavinosis, is uncommon in people eating a varied diet, but certain groups face higher risk.

• People with very restrictive diets or limited access to dairy, meat, or fortified grains
• People with chronic alcohol use, since alcohol can impair absorption and metabolism of riboflavin
• People with certain malabsorption conditions affecting the digestive tract
• Pregnant and breastfeeding people, due to increased needs
• People taking certain medications that interfere with riboflavin metabolism

Signs of deficiency can include cracks at the corners of the mouth, sore throat, inflamed tongue, and skin changes, though these symptoms overlap with other nutrient deficiencies and are not specific to riboflavin alone.

Riboflavin has a strong safety record even at higher supplemental doses.

No tolerable upper intake level has been established, largely because excess riboflavin is efficiently excreted in urine rather than accumulating to toxic levels.

The most noticeable side effect of high dose supplementation is a harmless bright yellow discoloration of urine.

As with any supplement, it is worth discussing new additions with a healthcare provider, especially at the high doses sometimes used in migraine research, and particularly if other medications or health conditions are involved.

Riboflavin is a foundational nutrient for energy metabolism, easily obtained through a varied diet that includes dairy, eggs, meat, and leafy greens.

Deficiency is uncommon but can occur in specific higher risk groups.

Interest in high dose riboflavin for migraine prevention is grounded in a reasonable biological theory, but the clinical evidence remains preliminary, so it is best viewed as a possible complementary option rather than a proven standalone treatment.