Vitamin B2 deficiency: symptoms affecting the mouth and skin, and who is affected
September 28, 2026approx. 15 minutesby mybody®x Editorial & Expert Team
Key takeaways
According to the DGE, vitamin B2 deficiency affects the skin and mucous membranes, for example causing an inflamed tongue or cracks at the corners of the mouth (DGE, 2025). It rarely occurs on its own and is usually accompanied by other nutrient deficiencies (DGE, 2025). Only a healthcare professional can determine whether too little riboflavin, the technical name for vitamin B2, is really the cause.
According to the DGE, severe deficiency can also cause anemia (DGE, 2025).
In Germany, average intake is around the recommended level or higher for almost all age groups, but lower for adolescents and young men. According to the DGE, this does not necessarily mean an inadequate intake (DGE, 2025).
In Germany, the main sources are milk and dairy products (DGE, 2025). Since riboflavin is very sensitive to light, the DGE recommends storing food in a dark place (DGE, 2015).
In this article
What does vitamin B2 do in the body?
According to the DGE, vitamin B2 is important for growth and development, and in cells it works as part of enzymes, including in energy and protein metabolism (DGE, 2025).
The technical name is riboflavin, and the DGE also describes it as important for cell function (DGE, 2025). As part of its coenzymes, riboflavin is a component of enzymes and is therefore involved in numerous reactions in the body (DGE, 2025). Enzymes are proteins that drive reactions in the body; coenzymes are helper molecules they work with. Here’s an analogy: the enzyme is the specialist, and the coenzyme is their tool.
Riboflavin is also involved in the metabolism of other B vitamins, including folate and pyridoxine, also known as vitamin B6 (DGE, 2025). Folate is also a B vitamin. A review suggests that a deficiency may produce some of its effects precisely by slowing the metabolism of folate and vitamin B6 (Powers, 2003).
The European Commission has approved the claim ‘Riboflavin contributes to the maintenance of normal skin’ for riboflavin, for foods that are at least a source of riboflavin (Regulation (EU) No. 432/2012). The claim describes the nutrient; it says nothing about skin complaints you may have.
How well supplied with vitamin B2 is Germany?
According to the DGE, average intake is roughly at or above the recommended intake for almost all age groups (DGE, 2025). This is based on the National Nutrition Survey II, a nationwide survey of what people in Germany eat, conducted in 2005 and 2006; it found that men aged 15 to 80 consumed an average of 1.4 mg of riboflavin per day, and women 1.2 mg (DGE, 2025).
For comparison, the DGE sets the reference value, or recommended intake, for adults aged 25 to under 51 at 1.4 mg per day for men and 1.1 mg for women (DGE, 2015).
There is still a gap, and according to the DGE, it is found precisely among the age groups with the highest reference values (DGE, 2025). On average, intake is lowest among adolescents of both sexes and young men, falling below the respective reference values (DGE, 2025). The DGE sets the highest reference value at 1.6 mg per day for male adolescents aged 15 to under 19 (DGE, 2025). However, according to the DGE, falling short of the reference values does not necessarily mean that someone has an inadequate intake or a deficiency (DGE, 2025).
Vitamin B2 is one of several B vitamins. The article Vitamin B1: Effects and requirements describes what thiamine, or vitamin B1, does in the body. The article Diseases caused by vitamin deficiencies explains the classic deficiency diseases and what they mean for us today.
Verified source
“Riboflavin deficiency on its own is rare.”
German Nutrition Society (DGE)
Selected questions and answers about riboflavin, 2025
What are the symptoms of vitamin B2 deficiency?
The DGE describes symptoms affecting the skin and mucous membranes, including inflammation of the oral mucosa and tongue (DGE, 2025). It also lists cracks at the corners of the mouth and scaly eczema on the skin, meaning inflammatory skin changes (DGE, 2025).
It starts with something you notice. One corner of your mouth is cracked, and it stays that way even though you apply cream. Eventually, you type a question into the search bar: could a vitamin be behind it? It’s a fair question: the DGE describes exactly these signs as symptoms of riboflavin deficiency (DGE, 2025).
What does a B2 deficiency look like in the mouth and on the tongue?
The DGE lists inflammation of the oral mucosa and tongue (DGE, 2025). Cracks at the corners of the mouth, known medically as angular cheilitis, are another symptom (DGE, 2025). You can see both in the mirror, but the mirror cannot show your nutrient levels.
What does a B2 deficiency look like on the skin?
The DGE lists scaly eczema as a skin symptom (DGE, 2025). Eczema is an inflammatory skin condition; scaly means that the skin flakes off in fine scales.
What happens in severe vitamin B2 deficiency?
According to the DGE, severe riboflavin deficiency can cause disorders of pyridoxine and niacin metabolism as well as anemia (DGE, 2025). Like pyridoxine, niacin is a B vitamin. The chapter Who Is Affected explains why iron may play a role.
How quickly does B2 status change?
Quickly, at least in the lab. According to a review, biochemical signs of depletion, meaning changes in lab values, appear just a few days after intake stops (Powers, 2003). Status here means the body’s nutrient supply. The review discusses lab values, not visible signs (Powers, 2003).
The direction of the conclusion matters. The DGE describes the signs of riboflavin deficiency and also notes that it usually occurs alongside deficiencies in other nutrients (DGE, 2025). So a cracked corner of the mouth alone does not mean you have a B2 deficiency. It is a warning light: it says it is worth taking a closer look, but not which nutrient is missing.
This article focuses on vitamin B2. The article What Happens When You Have a Vitamin B Deficiency describes vitamin B deficiency in general, with B2 mentioned only in passing: the whole group there, riboflavin here.
What causes vitamin B2 deficiency?
The DGE lists alcohol abuse and certain medications as factors that can contribute to the development of riboflavin deficiency (DGE, 2025). Another consideration is where the riboflavin in food comes from and what happens to it during cooking.
Without milk and dairy products: does that mean vitamin B2 is missing?
Not necessarily, but an important source is lost: milk and dairy products are the main sources of riboflavin in Germany (DGE, 2025). A review calls this unusual among water-soluble vitamins, since milk and dairy products contribute the most to intake in Western diets (Powers, 2003).
This does not support a judgment about a diet without milk; it only shows where intake comes from in Germany (DGE, 2025). Anyone replacing milk with plant-based drinks will find clear differences in the German Nutrient Database, maintained by the Max Rubner Institute (BLS 4.0, 2025). For example, a 200 g glass of unsweetened almond drink provides 0.041 mg of riboflavin, while a fortified one provides 0.42 mg according to the manufacturer (BLS 4.0, 2025).
For an unsweetened soy yogurt alternative, the value is below the detection limit, meaning below the smallest amount that can still be measured (BLS 4.0, 2025). The article Nutrient deficiencies on a vegan diet explains which nutrients are discussed in a diet without animal products.
Alcohol abuse: does it increase the risk of vitamin B2 deficiency?
Yes, according to the DGE, alcohol abuse increases the risk of developing riboflavin deficiency (DGE, 2025). Anyone who notices that alcohol has become a regular part of their everyday life can bring it up with their family doctor. They can also discuss their nutrient status there.
Medications: which ones increase the risk of vitamin B2 deficiency?
The DGE cites psychotropic drugs and chemotherapy drugs as examples (DGE, 2025). Psychotropic drugs are medications that affect the mind; chemotherapy drugs are used, among other things, to treat cancer.
The list is explicitly illustrative; the DGE refers to certain medications (DGE, 2025). This is not a reason to stop taking a prescribed medication. Ask the practice that prescribed it or a pharmacy about vitamin B2.
Light and cooking water: what happens to vitamin B2 in the kitchen?
Riboflavin is very sensitive to light and is therefore quickly converted into inactive substances (DGE, 2025). Inactive means these substances no longer act as a vitamin.
Water is also a factor. Riboflavin is water-soluble, and large amounts pass into the cooking water during cooking (DGE, 2015). If the cooking water is not used, this portion is lost (DGE, 2025). The DGE’s recommendations for the kitchen are explained in the chapter Foods with B2.
Who is most at risk of vitamin B2 deficiency?
Poor riboflavin status seems to affect older people and adolescents in particular in Western countries, according to a review (Powers, 2003). For Germany, the DGE identifies adolescents and young men whose average intake is below the reference value, although this does not necessarily mean they have an inadequate intake (DGE, 2025).
Notable is the closing remark in the same paper: poor status is seen despite the wide availability of riboflavin-rich foods (Powers, 2003). The review dates from 2003 and looks at Western countries as a whole, not Germany alone (Powers, 2003).
This also includes people in circumstances that the DGE says can promote a deficiency, namely alcohol abuse or taking certain medications (DGE, 2025). Anyone taking medication or with a pre-existing condition should first discuss vitamin B2 with their family doctor. More information is in the chapter The causes.
What does vitamin B2 have to do with iron?
According to a review, there is fairly good evidence that poor riboflavin status disrupts the body's handling of iron and contributes to the development of anemia when iron intake is low (Powers, 2003).
Two caveats apply. The review itself cautiously describes the evidence as fairly good, and the association applies when iron intake is also low (Powers, 2003). A family doctor's office can determine whether someone has anemia and what is causing it.
Which foods provide vitamin B2?
Milk and dairy products are the main sources in Germany (DGE, 2025). A sample 125 g portion of low-fat quark works out to 0.61 mg of riboflavin, or 56% of the reference value for women (BLS 4.0, 2025; DGE, 2015).
The DGE also lists fish as a good source (DGE, 2015). According to the DGE, organ meats such as liver and kidney contain particularly high amounts of riboflavin (DGE, 2025). It also highlights cereal germ flakes and, among cheeses, for example Camembert and mountain cheese (DGE, 2025).
The table calculates how much riboflavin a sample portion of ten foods provides and what percentage of the reference value that represents (BLS 4.0, 2025; DGE, 2015). The portions are estimates, not recommendations.
Vitamin B2 per example portion
| Food (example portion) | Vitamin B2, calculated (BLS 4.0, 2025) | Percentage of reference value for women / men (DGE, 2015) |
|---|---|---|
| Low-fat quark, 125 g (½ cup) | 0.61 mg | 56 % / 44 % |
| Unsweetened, fortified almond drink, 200 g (1 glass) | 0.42 mg (manufacturer's information) | 38 % / 30 % |
| Salmon, raw, 125 g | 0.38 mg | 34 % / 27 % |
| Almonds, 25 g (1 handful) | 0.30 mg | 28 % / 22 % |
| Mushrooms, raw, 100 g | 0.28 mg | 26 % / 20 % |
| Whole milk, 3.5% fat, 200 g (1 glass) | 0.28 mg | 25 % / 20 % |
| Plain yogurt, 3.5% fat, 150 g (1 cup) | 0.28 mg | 25 % / 20 % |
| Chicken egg, 55 g (1 egg without shell) | 0.28 mg | 25 % / 20 % |
| Broccoli, raw, 150 g | 0.18 mg | 16 % / 13 % |
| Camembert, 30 g (1 slice) | 0.11 mg | 10 % / 8 % |
Source: Max Rubner Institute, German Nutrient Database 4.0 (BLS 4.0, 2025); reference values for ages 25 to under 51: women 1.1 mg, men 1.4 mg per day (DGE, 2015). Example portions are estimates; values are calculated and rounded. For fortified almond drink, the riboflavin value is from the manufacturer (BLS 4.0, 2025).
Two things stand out. First, some dairy-free foods come close to a glass of whole milk: for example, a handful of almonds works out to 0.30 mg, compared with 0.28 mg for a glass of whole milk (BLS 4.0, 2025). Second, the figures are for foods before preparation, and what ends up on the plate also depends on how they are handled in the kitchen.
Because riboflavin is highly sensitive to light and large amounts leach into cooking water, the DGE recommends storing foods in the dark and using cooking water whenever possible (DGE, 2015). The article B Vitamins in Foods shows how vitamin B2 is distributed across foods compared with the other B vitamins.
How is vitamin B2 deficiency diagnosed?
In the lab, not in the mirror: The European Food Safety Authority considers the point where urinary riboflavin excretion levels off a laboratory value indicating adequate intake, and another value useful but limited (EFSA, 2017).
Its expert panel on nutrition derived reference values for riboflavin and also assessed laboratory values (EFSA, 2017). The panel considers the bend in the curve comparing urinary excretion with intake to be a sign that the body is saturated (EFSA, 2017).
The second value is called EGRAC, short for the erythrocyte glutathione reductase activation coefficient; glutathione reductase is an enzyme (EFSA, 2017). The panel considers EGRAC a useful laboratory value, but one with limitations (EFSA, 2017).
How difficult it is to determine the boundary between enough and too little is also shown in the review (Powers, 2003). Differences between dietary intake data and lab data suggest either that requirements are higher than previously assumed, or that the laboratory thresholds for deficiency are not appropriate (Powers, 2003).
There is no self-test, and no mybody®x (MYBODY Lab GmbH) test measures vitamin B2. You can discuss with your doctor which lab value makes sense in your case.
Chapter at a glance
Signs on the mouth and skin are a reason to ask questions, not a diagnosis. The European Food Safety Authority assesses riboflavin excretion in urine and EGRAC as laboratory values, though EGRAC has limitations (EFSA, 2017). No mybody®x test measures vitamin B2; questions about a deficiency should be discussed with a doctor.
What should you do if you suspect a vitamin B2 deficiency?
Signs on the mouth or skin that do not go away should be checked by your primary care doctor as a first point of contact. They can help determine whether a nutrient deficiency is actually the cause and which lab value would be useful.
For the appointment, it helps to make a brief note of when you first noticed the signs. Include the names of your medications on the list, as certain medications can promote riboflavin deficiency, according to the DGE (DGE, 2025).
For your kitchen, the table in the Foods with B2 section offers some guidance. The DGE allays concerns about getting too much from food: it finds no evidence of adverse health effects from high riboflavin intake from foods (DGE, 2025). This is a statement about safety, not a recommendation to take a supplement.
A blood test can still be useful, just not for vitamin B2. mybody®x offers the VitalCheck, an at-home blood test that shows, among other things, iron levels and vitamin B12. It can neither detect nor rule out a riboflavin deficiency, and its iron results do not indicate your vitamin B2 status.
A blood test such as VitalCheck is a good fit if …
you want to keep track of the levels measured by the test, such as iron and vitamin B12.
you’d like to bring a snapshot of these values to your doctor’s appointment.
Not a good fit if …
you want to check vitamin B2 – it doesn’t measure it.
you expect a diagnosis: It provides a snapshot, not a diagnosis.
From the mybody®x range · Blood test
VitalCheck Nutrient & Mineral Test Complete
At-home blood test: You collect the sample yourself, and it is analyzed by a specialist laboratory in Germany. It shows, among other things, iron levels and vitamin B12, but it does not measure vitamin B2. It provides a snapshot, not a diagnosis.
Lab analysis 3–5 business days after sample receipt
What does a cracked corner of the mouth say about vitamin B2?
It offers a clue, but not an answer. The DGE describes signs of riboflavin deficiency affecting the mouth and skin, while also noting that such a deficiency rarely occurs on its own (DGE, 2025).
So the more helpful question isn’t whether you’re deficient in vitamin B2, but how your overall supply is doing. A mirror can’t answer that; a conversation at your doctor’s office, where observations and lab results come together, can.
The corner of your mouth has done its job if it leads you there.
Frequently asked questions
How much vitamin B2 do you need per day?
For adults aged 19 to under 51, the DGE recommends 1.4 mg per day for men and 1.1 mg for women; from age 51, the amounts are 1.3 mg and 1.0 mg, respectively (DGE, 2015). These are reference values set by the professional society, not doses for a supplement. The European Food Safety Authority sets a higher reference intake of 1.6 mg per day for adults (EFSA, 2017). The difference shows that institutions calculate their values differently; the DGE values apply in Germany (DGE, 2015).
Why should milk be stored in the dark?
Because riboflavin is very sensitive to light and quickly converts into inactive substances when exposed to it (DGE, 2025). The DGE therefore advises storing foods in the dark (DGE, 2015). This is especially important for milk, as milk and dairy products are the main sources of riboflavin in Germany (DGE, 2025). A 200 g glass of whole milk, used here as an example serving, provides 0.28 mg—one quarter of the reference value for women (BLS 4.0, 2025; DGE, 2015).
Is vitamin B2 lost during cooking?
Yes, through the cooking water. Large amounts of water-soluble riboflavin can be lost during cooking if the cooking water is not used (DGE, 2025). The DGE therefore advises using the cooking water whenever possible (DGE, 2015). The German Food Code lists 0.27 mg per 100 g for dried lentils and 0.040 mg per 100 g for cooked lentils (BLS 4.0, 2025). However, this difference combines weight changes during cooking with the loss, so it does not represent cooking loss alone (BLS 4.0, 2025).
Can you get too much vitamin B2?
The DGE finds no evidence of adverse health effects from high riboflavin intake, including riboflavin from vitamin supplements (DGE, 2025). This does not mean supplements are recommended. Whether taking one makes sense in your case is something to discuss with your primary care practice, especially if you take medication.
Is vitamin B2 linked to anemia?
Yes, the sources describe a link. The DGE lists anemia as a symptom of severe riboflavin deficiency (DGE, 2025). A review finds fairly strong evidence that poor riboflavin status interferes with iron metabolism and contributes to anemia when iron intake is low (Powers, 2003). However, not all anemia is related to vitamin B2; your primary care practice can determine its cause.
Next step
Keep an eye on iron and vitamin B12
VitalCheck does not measure vitamin B2. It provides a snapshot of your iron and vitamin B12 levels to inform a discussion with your doctor.
Go to VitalCheck Other signs that may point to a vitamin deficiency An overview of vitamin deficiency symptomsRead more
Sources
- German Nutrition Society: Selected questions and answers about riboflavin (as of 2025) - dge.de
- German Nutrition Society: Reference values for nutrient intake, riboflavin (as of 2015) - dge.de
- Powers H. J.: Riboflavin (vitamin B-2) and health, American Journal of Clinical Nutrition (as of 2003) - europepmc.org
- Max Rubner Institute: German Nutrient Data Base 4.0 (as of 2025) - blsdb.de
Statements about function and symptoms are based on [1], as are the causes and supply situation in Germany. Reference values and information about light and cooking water come from [2]. The status in Western countries and the link with iron are based on [3], a review whose summary we evaluated; it also discusses the interpretation of laboratory data. Values per 100 g and per example serving are calculated from [4] (BLS 4.0, 2025). Laboratory values and the EFSA reference value are described in the opinion of the EFSA Panel on Nutrition (EFSA Journal, 2017, europepmc.org), while the authorized skin claim is set out in Regulation (EU) No. 432/2012, Official Journal L 136 of 25.05.2012. VitalCheck product information: as of 28.09.2026; subject to change. All sources checked on 28.09.2026.
mybody®x Editorial & Specialist Team
Vitamins Nutrition
This article was written by the mybody®x editorial and specialist team and reviewed against the sources listed above. Find out who is behind the content on the authors page.
Published on 28.09.2026 · Last updated on 28.09.2026
The content is for general information and is not a substitute for medical advice, diagnosis, or treatment. Reference ranges depend on the laboratory, method, and age - the information on your lab report is always authoritative.
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