Everything You Need To Know About Vitamin B2

07/06/2021 | 6 min. read

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There are many different B vitamins ranging from B1 to B12. While they are numbered up to 12, there are really eight different B vitamins. These vitamins are commonly found in the same foods, not synthesized by the body, and are essential to life.

Vitamin B2 is a water-soluble vitamin that is carried through the bloodstream and passes out of the body in urine. Our bodies need to consume vitamin B2 every day because it can only store as little as 27 mg, causing supply to go down rapidly.

Each vitamin also has a specific chemical name. For example, vitamin B2 is also known as riboflavin. Riboflavin is used in many different reactions throughout the body. Critically, it is used in two structured nucleotide coenzymes: flavin mononucleotide (FMN; also known as riboflavin-5’-phosphate) and flavin adenine dinucleotide (FAD). Most riboflavin is absorbed in the proximal small intestine.

From energy production to metabolism to homeostatic regulation, vitamin B2 plays an essential role. Let’s look at some of the most important vitamin B2 mechanisms.

Energy Production

One of the most common mechanisms where you will see vitamin B2 is in energy production. Riboflavin, vitamin B2, makes up one of the crucial parts of the FAD molecule. If you can recall back to your high school biology course, you might remember a process called The Krebs Cycle, Citric Acid Cycle, or Tricarboxylic Acid (TCA) Cycle.

The TCA cycle is the process by which the body maximizes the amount of energy it can get from breaking a single carbon-carbon bond. From a scientific perspective, everything is attached or, more appropriately, drawn to each other due to the different properties of that instance of matter in the grand scheme of its environment.

To work against the natural draw of a certain object requires energy. For instance, you need to exert force into the ground to overcome gravity, for a moment, and jump. Molecules have this principle applied to them as well.

When two molecules become bonded together, it takes energy to do so, and when that bond is broken, then energy is released like a spring. The more energy it takes to make the bond, the more energy is released when that bond is broken.

Loss of Energy

The issue that this creates in a biological context is that the large conversion of energy generally causes a loss of that energy in the form of heat instead of being harnessed. In addition, the body needs these large energy units that it can get from breaking a carbon-carbon bond to be used in smaller units.

The TCA Cycle is a series of reactions that cause slow oxidation of that carbon-carbon bond, allowing the body to fully maximize that energy. To do this reaction, the body needs energy carrier molecules, like NAD+ and FAD, and nutrients in the form of Acetyl-CoA.

Acetyl-CoA is a small molecule that the body makes from fats, sugars, and proteins. The body’s chemical mechanisms make it so that sugars are used initially for the synthesis of Acetyl-CoA.

Once the body gets Acetyl-CoA, then it puts it through the TCA cycle causing the B3 and B2 vitamin-based electron carrier molecules NAD+ and FAD to pick up the extra electrons. They move the electrons to the electron transport chain, which is a series of enzymes that use the electrons to create a charge differential across the inner membrane of the mitochondria. This charge differential facilitates the production of ATP, which is the molecule used for energy throughout the body.

Other Properties of Vitamin B2

Riboflavin has many other important roles in the body, including activation of vitamin B6 and vitamin B9, protein folding, reducing oxidative stress, modulating immune responses, and acting as an anti-inflammatory.

Vitamin B2 and Light

Riboflavin is an extremely light-sensitive molecule. When people undergo extended periods of light therapy, then they can lose some of the available vitamin B2 in their body. This is particularly important for children and newborns who can develop a riboflavin deficiency in response to extended light therapies.

Also, the loss of riboflavin to light is one of the reasons that milk is typically packaged in opaque containers. The light sensitivity of vitamin B2 is also what makes it such a useful component of blue light receptors, phototropins, in some organisms.

Vitamin B2 Testing

Riboflavin deficiency is extremely rare, and those suffering from it typically have deficiencies in many other vitamins as well, making it difficult to distinguish what the specific symptoms are.

Some of the most common symptoms of vitamin B2 deficiency include:

  • Edema of the mouth and throat
  • Cheilosis (swollen, cracked lips)
  • Hyperemia (excess blood)
  • Hair loss
  • Sore throat
  • Itchy and red eyes
  • Angular stomatitis (lesions at the corners of the mouth)
  • Reproductive issues
  • Degeneration of the liver and nervous system

Because of the rarity of the deficiency and ease of prevention, most healthy people will not need their vitamin B2 level tested.

People who may be at risk of developing a vitamin B2 deficiency include people who do not eat meat or dairy products, who are growing or have demanding conditions, such as:

  • Pregnant women
  • Lactating women
  • Infants

There is also a rare neurological disorder called riboflavin transporter deficiency that will also cause riboflavin deficiency amongst other, more severe symptoms.

Vitamin B2 Treatments

The use of vitamin B2 as a treatment for the disease is pretty limited. A high dose B2 supplement has been shown to be beneficial to those with:

Riboflavin transporter deficiency

This disease makes it difficult for the body to absorb vitamin B2. The high dose of riboflavin may allow for small amounts of it to be absorbed into the body.


Mitochondrial dysfunction is thought to be one of the key factors for certain types of migraine headaches. Since riboflavin is integral to proper mitochondrial function then it may play a role in reducing these types of headaches. Research in this area is still ongoing.


This disease has been shown to create a significant vitamin B2 deficiency in the body. A high dose of riboflavin may help restore this.

Elevated Homocysteine

The reduction of homocysteine by about 25% has been correlated with a significantly lower risk of coronary heart disease. Taking riboflavin has been shown to decrease levels of homocysteine in the blood by up to 22% for people with a specific genotype.

Taking vitamin B2 to heighten the activation of vitamins B9 and B6 may also be helpful in lowering homocysteine for people taking anti-seizure medications.

The supplementation with B vitamins (B6, B9 and B12) has been shown to lower homocysteine levels by 25% for people with high homocysteine levels due to anti-seizure medication.


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.

Foods Rich in Vitamin B2

The recommended dietary allowance (RDA) of riboflavin for adults is 1.3 mg for males and 1.1 mg for females. You can find vitamin B2-rich foods in eggs, lean meats like beef, organ meats (kidney and liver), chicken, and milk products such as cheese and yogurt. Green vegetables such as broccoli, spinach, brussel sprouts, green peas, are also good sources of riboflavin.


Vitamin B2, also known as riboflavin, is an essential nutrient that the body needs for multiple different mechanisms throughout the body. One of the most important and well-known of these mechanisms is its use as an electron carrier molecule for the production of ATP through the electron transport chain.

Vitamin B2 is very light-sensitive and can be found in meats and dairy products. Not many people develop a vitamin B2 deficiency unless they are malnourished and have underlying causes.

If you are concerned about not getting enough vitamin B2, consider eating more meat and dairy products or try a vitamin B complex supplement.

Healthy Directions Staff Editor