7 Surprising Symptoms of Vitamin B2 Deficiency

Plus, how much of the vitamin you actually need.

Published on Feb. 17, 2026

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Vitamin B2, or riboflavin, plays a crucial role in energy levels, metabolism, and cell growth. While deficiency is uncommon in the U.S., certain groups like those with thyroid issues, vegetarians/vegans, and pregnant/breastfeeding women are at higher risk. Experts reveal the top signs of B2 deficiency, including fatigue, cracked lips, sore throat, and reproductive issues. They also share the recommended daily intake and top food sources of this important nutrient.

Why it matters

Recognizing the signs of vitamin B2 deficiency is important, as it can impact energy, skin/hair health, and even fertility. Knowing your risk factors and how to get enough riboflavin through diet or supplements can help prevent potential health issues down the road.

The details

Vitamin B2 deficiency is not very common in the U.S., but certain groups have a higher risk, including those with thyroid issues, vegetarians/vegans, and pregnant/breastfeeding women. Symptoms of low B2 can include fatigue, cracked lips, crusty mouth corners, scaly skin patches, sore throat, and unexplained hair loss. Fertility issues like problems with sperm/egg development and early embryo growth have also been linked to riboflavin deficiency. The recommended daily intake varies by age and life stage, with most adult women needing 1.1 mg and men 1.3 mg. Top food sources include beef liver, fortified cereals, oats, yogurt, and milk.

  • Vitamin B2 deficiency is more common in certain groups, including those with thyroid issues, vegetarians/vegans, and pregnant/breastfeeding women.

The players

Ife J. Rodney, M.D.

A dermatologist and founding director of Eternal Dermatology + Aesthetics.

Christine Greves, M.D.

An ob/gyn at the Winnie Palmer Hospital for Women and Babies in Orlando, Florida.

Scott Keatley, R.D.

Co-owner of Keatley Medical Nutrition Therapy.

Jessica Cording, R.D.

Author of The Little Book of Game-Changers.

Keri Gans, R.D.N.

A dietitian and host of The Keri Report podcast.

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What they’re saying

“Riboflavin helps your body convert carbohydrates into fuel and plays a big role in how your cells produce energy. Fatigue can happen when that process breaks down.”

— Keri Gans, R.D.N., dietitian and host of The Keri Report podcast (prevention.com)

“Riboflavin helps with moisture retention. If you're low in the nutrient, your lips' natural moisture can suffer as a result, leading to cracking and even bleeding.”

— Ife J. Rodney, M.D., dermatologist and founding director of Eternal Dermatology + Aesthetics (prevention.com)

“Since riboflavin is also crucial for overall cell function, low levels can affect fast-healing areas like the skin and mouth, leading to symptoms like a sore throat.”

— Keri Gans, R.D.N., dietitian and host of The Keri Report podcast (prevention.com)

“Fertility is incredibly complicated, and it's hard to say that adding more B2 to your diet will magically help you conceive. But not having enough riboflavin can interfere with several areas of reproduction, including the development of sperm and eggs, ovulation, and early development of the embryo.”

— Christine Greves, M.D., ob/gyn at the Winnie Palmer Hospital for Women and Babies in Orlando, Florida (prevention.com)

“Some individuals experience digestive discomfort, nausea, or bloating from taking vitamin B2 supplements. Excess riboflavin can turn urine bright yellow, which is harmless but sometimes alarming.”

— Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy (prevention.com)

What’s next

If you suspect you may have a vitamin B2 deficiency, it's important to see a healthcare provider for a proper evaluation, including a blood test to determine the extent of the deficiency. They can then provide guidance on the best course of action, whether that's adjusting your diet or taking a supplement.

The takeaway

Recognizing the signs of vitamin B2 deficiency, which can include fatigue, skin/hair issues, and reproductive problems, is key for those at higher risk. Making sure to get enough riboflavin through a balanced diet or supplements can help prevent potential health issues down the road.