Vitamin B2 or Riboflavin

Riboflavin is a B vitamin that is involved in many processes in the body and is necessary for normal cell growth and function.

Updated: April 30, 2019

Riboflavin is a B vitamin that is involved in many processes in the body and is necessary for normal cell growth and function. It is needed to keep your skin, eyes, nerves,  lining of the digestive tract and red blood cells healthy. It is used to prevent or treat low levels of vitamin B2 in people who do not get enough of the vitamin from their diet. Most people who eat a normal diet do not need extra vitamin B2.
It can be found in certain foods such as milk, meat, eggs, nuts, enriched flour, and green vegetables. However, some conditions (such as stomach/intestinal problems, prolonged infection, liver disease, alcoholism, cancer) can cause low levels of vitamin B2. Riboflavin is frequently used in combination with other B vitamins in vitamin B complex products. Vitamin B2 is a water-soluble vitamin, so it dissolves in water. All vitamins are either water soluble or fat soluble. Water-soluble vitamins are carried through the bloodstream, and the excess amount is passed out from the body in urine.
As the body can only store small amounts of this vitamin and supplies go down rapidly, people need to consume vitamin B2 every day. Most of it is absorbed in the small intestine.

Importance of Vitamin B2:

Vitamin B2 helps break down proteins, fats, and carbohydrates. It plays a vital role in maintaining energy level of the body. Riboflavin helps convert carbohydrates into adenosine triphosphate (ATP). The human body produces ATP from food, and ATP produces energy as the body requires it. The compound ATP is vital for storing energy in muscles.
Vitamin B is essential for:

  •     Maintaining the mucous membranes in the digestive system
  •     Maintaining a healthy liver
  •     Converting tryptophan into niacin, an amino acid
  •     Keeping the eyes, nerves, muscles and skin healthy
  •     Absorbing and activating iron, folic acid, and vitamins B1, B3 and B6
  •     Hormone production by the adrenal glands
  •     Preventing the development of cataracts
  •     Fetal development, especially in areas where vitamin deficiency is common

Vitamin B2 may help prevent cataracts and migraine headache. In children with autism, supplements of vitamins B2, B6, and magnesium appear to reduce the levels of abnormal organic acids in the urine.

Dietary Sources:

Meat, fish, and dairy products provide vitamin B2.
Sources of B2 include:

  • Fish, meat, and poultry, such as turkey, chicken, beef, kidneys, and liver
  • Eggs
  • Dairy products
  • Asparagus
  • Artichokes
  • Avocados
  • Cayenne
  • Currants
  • Fortified cereals
  • Kelp
  • Lima beans, navy beans, and peas
  • Molasses
  • Mushrooms
  • Nuts
  • Parsley
  • Pumpkins
  • Rosehips
  • Sage
  • Sweet potatoes
  • Cruciferous vegetables, such as broccoli, Brussels sprouts, spinach, dandelion greens, and watercressWhole-grain breads, enriched breads, and wheat bran
  • Yeast extract

As Vitamin B2 is water soluble, cooking these food can cause it to be lost. About twice as much B2 is lost through boiling as it is through steaming or microwaving.


As the human body excretes the vitamin continuously, so it is not stored in our body. Hence, Vitamin B2 deficiency is a significant risk when diet is poor. A person who has a B2 deficiency normally lacks other vitamins too.
There are two types of riboflavin deficiency:
Primary riboflavin deficiency happens when the person's diet is poor in vitamin B2
Secondary riboflavin deficiency happens for another reason, maybe because the intestines cannot absorb the vitamin properly, or the body cannot use it, or because it is being excreted too rapidly. Riboflavin deficiency is also known as ariboflavinosis.
A lack of vitamin B2 can lead to mouth ulcers and other complaints.

Signs and symptoms of deficiency include:

  •     Angular cheilitis, or cracks at the corners of the mouth
  •     Cracked lips
  •     Dry skin
  •     Inflammation of the lining of the mouth
  •     Inflammation of the tongue
  •     Mouth ulcers
  •     Red lips
  •     Sore throat
  •     Scrotal dermatitis
  •     Fluid in mucous membranes
  •     Iron-deficiency anemia
  •     Eyes may be sensitive to bright light, and they may be itchy, watery, or bloodshot

People who drink excessive amounts of alcohol are at greater risk of vitamin B deficiency.

Uses & Effectiveness:

Effective for:

Preventing and treating low riboflavin levels (riboflavin deficiency):
Taking riboflavin by mouth can increase levels of riboflavin in the body of adults as well as children who have too little riboflavin in their body.

Possibly Effective for:


People who eat more riboflavin as part of their diet seem to have a lower risk of developing cataracts. Also, taking supplements containing riboflavin plus niacin seems to help prevent cataracts.


It is a condition with high amounts of homocysteine in the blood. Taking riboflavin by mouth for 12 weeks decreases levels of homocysteine in some people. Also, taking riboflavin along with folic acid and pyridoxine seems to be more effective in lowering homocysteine levels in people with high homocysteine levels caused by drugs that are used to prevent seizures.

Migraine headaches:

Taking high-dose riboflavin by mouth seems to reduce the number of migraine headache attacks, by about 2 attacks per month. Taking riboflavin in combination with other vitamin sand minerals seems to also reduce the amount of pain experienced during a migraine.

Possibly Ineffective for:

Stomach cancer:

Taking riboflavin along with niacin does help prevent gastric cancer.


Malnutrition caused by too little protein in the diet is called as Kwashiorkor. Taking riboflavin, vitamin E, selenium, and N-acetyl cysteine by mouth does not reduce fluid, increase height or weight, or decrease infections in children who are at risk for kwashiorkor.

Lung cancer:

Taking riboflavin by mouth along with niacin does not help prevent lung cancer.


Taking riboflavin along with iron, thiamine, and vitamin C by mouth, does not reduce the number or seriousness of malaria infections in children who are at risk of being exposed to malaria.


High blood pressure during pregnancy is known as Pre-eclampsia. In women, starting to take riboflavin from 4 months pregnancy by mouth does reduce the risk of pre-eclampsia during pregnancy.

Insufficient Evidence for:

Lactic acidosis:

It is a serious blood-acid imbalance in people with acquired immunodeficiency syndrome (AIDS). Taking riboflavin by mouth might by helpful for treating lactic acidosis caused by drugs called nucleoside analog reverse transcriptase inhibitors (NRTIs) in patients with acquired immunodeficiency syndrome (AIDS).

Cervical cancer:

Increasing intake of riboflavin from dietary and supplement sources, along with thiamine, folic acid, and vitamin B12, might decrease the risk of developing cervical cancer.

Eesophageal cancer:

The effect of riboflavin for preventing esophageal cancer is conflicting. Taking riboflavin by mouth may decrease the risk of getting esophageal cancer in some people, while it has no effect for others.

High blood pressure:

Taking riboflavin by mouth in certain patients at higher risk of high blood pressure due to genetic differences may lower blood pressure when used in addition to prescribed blood pressure medications.

Liver cancer:

Taking riboflavin and niacin by mouth might reduce the risk of liver cancer in people less than 55 years-old. However, it does not seem to reduce the risk of liver cancer in older people.

Multiple sclerosis:

Taking riboflavin by mouth for 6 months does not improve disability in patients with multiple sclerosis.

Oral Leukoplakia:

Low levels of riboflavin in the blood are linked with an increased risk of oral leukoplakia a condition with white patches inside the mouth. However, taking riboflavin supplements by mouth for 20 months does not seem to prevent or treat oral leukoplakia.

Iron deficiency during pregnancy:

Taking riboflavin, iron, and folic acid by mouth does not increase iron levels in pregnant women more than taking just iron and folic acid.

Sickle cell disease:

Taking riboflavin by mouth for 8 weeks increases iron levels in people with low iron levels due to sickle cell disease.


Taking riboflavin and niacin by mouth does not prevent stroke-related death in people at risk for stroke.
More evidence is needed to rate the effectiveness of riboflavin for the uses in below condition:.   

  •     Acne.
  •     Aging.
  •     Boosting the immune system.
  •     Canker sores.
  •     Maintaining healthy skin and hair.
  •     Memory loss including Alzheimer's disease.
  •     Muscle cramps.
  •     Other conditions.

Side Effects & Safety:

Riboflavin is likely safe for most people when taken by mouth. In some people, riboflavin can cause the urine to turn a yellow-orange color. It may also cause diarrhea.
However, this effect is harmless and will disappear when the vitamin is stopped. Many people using this medication do not have serious side effects.
A very serious allergic reaction to this vitamin is rare. Get medical help right away if you notice any symptoms of a serious allergic reaction, including rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Special Precautions & Warnings:


Riboflavin is likely safe for most children when taken by mouth in appropriate amounts as recommended by the Food and Nutrition Board for the National Institute of Medicine.

Pregnancy and breast-feeding:

Riboflavin is likely safe when taken by mouth and used appropriately for pregnant or breast-feeding women. The recommended amounts are 1.4 mg per day for pregnant women and 1.6 mg per day in breast-feeding women. Riboflavin is possibly safe when taken by mouth in larger doses, short-term. Riboflavin is safe when taken at a dose of 15 mg once every 2 weeks for 10 weeks.

Hepatitis, Cirrhosis, Billary obstruction:

Riboflavin absorption is decreased in people with these conditions.


Be watchful with the combination as these can have minor interaction:

Drying medications (Anticholinergic drugs) interacts with Vitamin B2:

Some drying medications can affect the stomach and intestines. Taking these drying medications with riboflavin (vitamin B2) can increase the amount of riboflavin that is absorbed in the body.

Medications for depression (Tricyclic antidepressants) interacts with Vitamin B2:

Some medications for depression can decrease the amount of riboflavin in the body. This interaction is not a big concern because it only occurs with very large amounts of some medications for depression.

Phenobarbital (Luminal) interacts with Vitamin B2:

Riboflavin is broken down by the body. Phenobarbital might increase how quickly riboflavin is broken down in the body.

Probenecid (Benemid) interacts with Vitamin B2:

Probenecid (Benemid) can increase how much riboflavin is in the body. This might cause there to be too much riboflavin in the body.


The following doses have been studied in scientific research and is recommended:


By Mouth:


The recommended dietary allowance (RDA) of riboflavin for adults is

  • 1.3 mg per day for males
  • 1.1 mg per day for women
  • 1.4 mg per day for pregnant females
  • 1.6 mg per day for lactating women.

There is no daily Upper Intake Levels (UL) for riboflavin, which is the highest level of intake that is likely to pose no risk of adverse effects.

For preventing and treating low levels of riboflavin (riboflavin deficiency):

Riboflavin 5-30 mg daily has been used.

For cataracts:

A combination of riboflavin 3 mg plus niacin 40 mg daily for 5-6 years has been used.

For high levels of homocysteine in the blood:

Riboflavin 1.6 mg daily for 12 weeks has been used. A combination containing 75 mg of riboflavin, 0.4 mg of folic acid, and 120 mg of pyridoxine daily for 30 days has also been used.

For migraine headaches:

The most common dose is riboflavin 400 mg daily for at least three months. A specific product (Dolovent; Linpharma Inc., Oldsmar, FL ) dosed at two capsules in morning and two capsules in the evening for 3 months has also been used. This dose provides a total of riboflavin 400 mg, magnesium 600 mg, and coenzyme Q10 150 mg per day.


By Mouth:


The recommended dietary allowance (RDA) of riboflavin is

  • 0.3 mg per day for infants up to 6 months old
  • 0.4 mg per day for infants 6-12 months old
  • 0.5 mg per day for children 1-3 years old
  • 0.6 mg per day for children 4-8 years old
  • 0.9 mg per day for children 9-13 years old
  • 1.3 mg per day for males 14-18 years old
  • 1.0 mg per day for females 14-18.

There is no daily Upper Intake Levels (UL) for riboflavin, which is the highest level of intake that is likely to pose no risk of adverse effects.

For preventing and treating low levels of riboflavin (riboflavin deficiency):

Riboflavin 2 mg once, then 0.5-1.5 mg daily for 14 days has been used. Riboflavin 2-5 mg daily for up to two months has been used. Riboflavin 5 mg five days per week for up to one year has also been used.

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