Riboflavin (Vitamin B2): Everything You Should Know

Medically reviewed by Allison Herries, RDN

Riboflavin, also known as vitamin B2, is a key vitamin required by the human body. It is an essential part of important enzymes in the body and plays a role in energy production, growth and development, and metabolism.

Riboflavin occurs naturally in some foods and is added to some food products. It is also available in supplement form.

This article reviews riboflavin, who may be at risk of deficiency, and when and how much to consume.

Dietary supplements are not regulated the way drugs are in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Whenever possible, choose a supplement tested by a trusted third party, such as the U.S. Pharmacopeia (USP), ConsumerLab, or NSF. 

However, even if supplements are third-party tested, they are not necessarily safe for all or effective in general. Therefore, talking to your healthcare provider about any supplements you plan to take and asking about potential interactions with other supplements or medications is essential.

Supplement Facts

• Active ingredient(s): Riboflavin

• Alternate name(s): Vitamin B2

• Suggested dose: For healthy people, follow the Recommended Dietary Allowance (RDA); no standard dose for treating deficiencies

• Safety considerations: Relatively safe; no known interactions
  

Benefits of Riboflavin

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Riboflavin is an essential part of two major coenzymes in the body: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These enzymes:

• Produce energy in the body

• Help with growth and development

• Break down fats, drugs, and steroids

Riboflavin also helps to maintain normal homocysteine levels. High levels of homocysteine have been associated with heart disease. Additionally, FAD is required for the amino acid tryptophan to convert to niacin (a form of vitamin B3), and FMN is required for vitamin B6 to convert to an enzyme called pyridoxal 5'-phosphate.

Riboflavin in Research

Research has looked at riboflavin for its potential role in certain health conditions, including cancer and migraine.

Cancer

Although riboflavin has been studied for its role in cancer prevention, there is not enough evidence to support taking high doses of riboflavin for this purpose. Nor does riboflavin have any role in cancer treatment at this time.

A large study that focused on the diet quality of over 386,000 participants assessed the risk of developing colorectal cancer. Among other nutrients, higher intakes of riboflavin were associated with a lower risk of colorectal cancer.

Some research has shown that higher intakes of riboflavin are associated with a reduced risk of breast cancer. However, the authors noted a weak relationship between riboflavin intake and breast cancer risk.

More research is needed before recommending riboflavin supplementation for cancer prevention. In the meantime, a daily diet rich in fruits and vegetables, whole grains, and lean proteins is recommended.

Migraine Prevention

Migraines are thought to be caused by mitochondrial dysfunction, and riboflavin plays a key role in mitochondrial function.

High-dose riboflavin for migraine prevention has been studied. A 2017 systematic review (a review of studies focused on a single question) found that riboflavin supplementation effectively reduced the frequency of migraines.

In another review, 400 milligrams (mg) daily of riboflavin had a significant effect on days, duration, and severity of migraine.

If you have migraines, talk to your healthcare provider about all available treatment options.

Riboflavin Deficiency

Riboflavin deficiency is rare in developed countries but can occur in special circumstances. In the United States, a person with riboflavin deficiency will likely have multiple deficiencies or general malnutrition due to a medical condition.

In the case of a deficiency, supplementing riboflavin is recommended.

Treating a riboflavin deficiency may be better done with a multivitamin if deficiencies in other nutrients are suspected. At a minimum, the RDA amounts of riboflavin should be provided with an oral supplement. Riboflavin supplements should be taken with meals for better absorption.

If oral supplements are not an option, injections or intravenous sources of riboflavin are also available.

What Causes a Deficiency?

Deficiency occurs from too little nutrient intake or poor absorption and use of a particular nutrient.

People with very restrictive diets may not be able to get enough riboflavin. Dairy, eggs, and meats are all good sources of riboflavin. People who do not consume animal products may not get enough riboflavin in their diet.

Riboflavin is absorbed in the proximal small intestine. People who have had surgical resections of the proximal small intestine may not be able to absorb enough riboflavin.

Groups at Risk of a Riboflavin Deficiency

The following groups may be at greater risk of developing a riboflavin deficiency:

• Athletes who do not consume animal products require more riboflavin due to the stress that occurs from exercise

• Pregnant and lactating people, who require more riboflavin, may be at risk mainly if they don't consume meat or dairy.

• People with riboflavin transporter deficiency, a rare neurological disorder in which riboflavin can't properly be absorbed and transported, may have a deficiency.

• People with surgical resections that involve the proximal small intestine, the site of absorption for riboflavin, may have a deficiency.

How Do I Know If I Have a Deficiency?

A classic sign of riboflavin deficiency is cracking of the skin, itching, or dermatitis around the mouth. Riboflavin deficiency may also lead to:

• Swollen or sore throat

• Red eyes

• Hair loss

Talk to your healthcare provider if you suspect you may have a riboflavin deficiency. Riboflavin status is not routinely measured, but providers can order tests to check if you have a deficiency.

An erythrocyte glutathione reductase activity coefficient (EGRAC) level can be ordered to assess riboflavin status. Coefficients greater than 1.4 indicate a deficiency.

What Are the Side Effects of Riboflavin?

Very few side effects have been reported with riboflavin supplementation. In some cases, nausea has been reported.

Dosage: How Much Riboflavin Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

Riboflavin is an essential nutrient and there is an RDA set for the minimum amounts needed to prevent deficiency.

What Happens If I Take Too Much Riboflavin?

There are no reports of riboflavin toxicity. Only a tiny amount of the riboflavin obtained through the diet is absorbed and used by the body. Any excess riboflavin consumed is excreted through urine.

There is no tolerable upper limit (TUL) established for riboflavin.

Interactions

There are no known interactions of riboflavin supplements with medications. That said, it is always important to look at all of the ingredients in a supplement and assess the safety of each ingredient.

It is essential to carefully read the ingredients list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How to Store Riboflavin

Follow the manufacturer's instructions for storage of riboflavin. Riboflavin is sensitive to light; too much light exposure can make it less effective.

Always keep medications and supplements stored where they are out of reach of children and pets.

Frequently Asked Questions

What does riboflavin do in the body?

Riboflavin is an essential nutrient. It is a crucial component to the enzymes FMN and FAD. These enzymes help with energy production, growth, development, and maintaining normal homocysteine levels.

Should I take riboflavin daily?

Like most B vitamins, riboflavin is an essential nutrient. Always try to get your nutrients (including riboflavin) through diet first. Eggs, dairy, some meats, and whole grain products are good sources of riboflavin.

If you are concerned about your diet and nutrient intake, riboflavin could be supplemented by taking a multivitamin daily. Most multivitamins contain riboflavin and provide RDA amounts.

Sources of Riboflavin & What to Look For

Riboflavin is readily available in many of the foods we eat. It occurs naturally in the following foods:

• Beef liver, beef, chicken, and salmon

• Milk, yogurt, and cheese

• Mushrooms, spinach, and apples

Riboflavin, along with other B vitamins, is added to some grain products, such as:

• Oats

• Breakfast cereals (fortified with riboflavin)

Riboflavin is available as a single supplement, a B-complex with multiple vitamins, or a multivitamin.

As a single nutrient supplement, Riboflavin is available in 25-, 50-, or 100-mg tablets. Most multivitamins provide at least 1.3 mg (or 100% of the RDA).

When looking at supplements, always look for brands that have been third-party tested.

Summary

Riboflavin is an essential nutrient with several functions in the human body. While supplementation may be needed in some cases, riboflavin can usually be obtained through eating foods like certain meats and dairy products (e.g., milk or cheese)

Although rare, riboflavin deficiency may require supplementation. Daily multivitamins may also contain riboflavin. When choosing riboflavin-containing supplement products, review the label and ingredients with your healthcare provider to make sure the product is right for you.