What Happens if You Have Too Little B2?

November 30, 2025 •

3 min read

According to the NIH, severe riboflavin deficiency can diminish levels of FAD and FMN, affecting the metabolism of other vital nutrients. A deficiency in vitamin B2, also known as riboflavin, can impact your body in several ways, from causing skin and mouth issues to more systemic problems.

Quick Summary

This article explores the symptoms and causes of riboflavin deficiency, also known as ariboflavinosis, detailing how a lack of B2 impacts energy production, skin health, and other crucial bodily functions. It also provides information on at-risk groups and steps to address the deficiency.

Key Points

Oral Symptoms: Painful cracks at the corners of the mouth (angular cheilitis) and a sore, swollen, magenta-colored tongue (glossitis) are common signs of low B2.
Skin Conditions: Ariboflavinosis can cause oily, scaly rashes known as seborrheic dermatitis, typically around the face and genitals.
Eye Irritation: Symptoms can include itchy, bloodshot eyes and increased sensitivity to light (photophobia).
Anemia: A B2 deficiency can disrupt iron metabolism, potentially leading to a specific type of anemia.
High-Risk Groups: Individuals with alcoholism, malabsorption issues, pregnant women, and the elderly are at a higher risk of developing a riboflavin deficiency.
Dietary Prevention: Consuming riboflavin-rich foods like milk, eggs, lean meats, and fortified cereals is the best way to prevent deficiency.
Reversibility: Many of the initial symptoms of low B2 are reversible with proper treatment and increased intake of the vitamin.

What is Vitamin B2 (Riboflavin)?

Vitamin B2, or riboflavin, is an essential water-soluble vitamin vital for energy production as a component of FMN and FAD coenzymes. These coenzymes are crucial for the metabolism of carbohydrates, fats, and proteins. Since the body doesn't store much riboflavin, regular dietary intake is needed to prevent deficiency.

Symptoms of Too Little Vitamin B2

Riboflavin deficiency, or ariboflavinosis, can cause various symptoms, often alongside other B vitamin deficiencies. Early signs are often reversible with supplementation.

Common physical symptoms include:

Cracked and swollen lips (cheilosis) and painful lesions at the mouth corners (angular stomatitis).
A sore, magenta-colored tongue (glossitis).
Oily, scaly skin rashes (seborrheic dermatitis) on the face and genital areas.
Itchy, red eyes and light sensitivity (photophobia).
Fatigue and weakness from impaired energy conversion.
Sore throat and inflammation of the mouth lining.

More severe and long-term effects may include:

Anemia, due to impaired iron metabolism.
Cataracts in chronic cases.
Nervous system degeneration.
Developmental issues like heart defects or cleft palate if deficient during pregnancy.

Causes and Risk Factors

While uncommon in developed nations with fortified foods, certain groups face a higher risk of riboflavin deficiency. Causes can be poor diet (primary) or poor absorption/increased need (secondary).

Poor diet, especially in areas lacking dairy and meat.
Alcoholism, which hinders absorption and metabolism.
Chronic conditions like celiac or liver disease.
Increased needs during pregnancy, lactation, or illness.
Certain endocrine issues or medications.

How to Address Low B2 Levels

Improving riboflavin levels involves diet and supplements. Excess riboflavin is water-soluble and excreted, so toxicity is rare.

Dietary Sources

Dairy products like milk and yogurt.
Meats, particularly organ meats.
Fortified grains and cereals.
Green vegetables such as spinach.
Eggs and almonds.

Supplementation

Oral supplements (10–20 mg/day) may be recommended for mild deficiencies.
A B-complex supplement is often advised as deficiencies can involve multiple B vitamins.

Comparison of Riboflavin Deficiency Effects


Body System	Early Symptoms	Severe or Chronic Symptoms
Mouth & Lips	Angular cheilitis (cracked mouth corners), glossitis (magenta tongue), and sore throat.	Painful fissures that can become infected with Candida albicans.
Skin	Seborrheic dermatitis with oily, scaly rashes around the nose, ears, and genitalia.	Generalized dermatitis and other skin disorders.
Eyes	Itchy, watery, and bloodshot eyes, with sensitivity to light (photophobia).	Neovascularization of the cornea and cataracts.
Hematologic	Inability to metabolize iron efficiently, leading to normochromic normocytic anemia.	More severe, prolonged anemia.
Systemic	Fatigue, weakness, and impaired metabolism.	Potential for liver degeneration and nervous system damage.

Conclusion

A deficiency of vitamin B2, or riboflavin, can lead to a range of uncomfortable and, in severe cases, dangerous health issues. From visible symptoms like cracked lips and a sore tongue to underlying systemic problems such as anemia and neurological damage, the impact of too little B2 is significant. While rare in well-nourished populations, those with poor dietary habits, alcoholism, or certain health conditions are at heightened risk. Fortunately, most early symptoms are easily reversible with increased dietary intake of riboflavin-rich foods like dairy, meat, and fortified grains, or with supplements under a doctor's guidance. Early detection and treatment are key to preventing more serious, long-term complications.

Clinical presentation and outcome of riboflavin transporter deficiency

Frequently Asked Questions

A vitamin B2 deficiency is also known as ariboflavinosis.

A magenta tongue, or glossitis, is an inflamed, swollen, and discolored tongue that can result from low riboflavin levels.

Riboflavin deficiency is rare in developed countries with widespread food fortification, but it is more common in developing regions and among specific high-risk groups.

Early signs of low B2 can include cracked lips, sores at the corners of the mouth, a sore throat, fatigue, and red or itchy eyes.

Good food sources of riboflavin include dairy products (milk, yogurt), meats (especially liver), eggs, almonds, and fortified cereals.

Yes, a deficiency in riboflavin can interfere with iron absorption and metabolism, which can lead to a type of anemia.

Riboflavin is water-soluble, so excess amounts are typically excreted in the urine. For this reason, a tolerable upper intake level has not been established, and toxicity is rare from oral supplements.