Vitamin B
- Fast shipping
- 3000+ products in stock
- 1.000.000+ customers
Fatigue that doesn't disappear even after the weekend, tingling in the hands, or cracked corners of the mouth. These are all signs of a deficiency in B-vitamins—a group of eight nutrients that work closely together. Should you be supplementing the whole B-complex, or just B12? And do you actually need to supplement it at all? Read on to find out.
What is vitamin B and why isn't it just one vitamin?
Vitamin B is not a single substance, but a group of eight water-soluble vitamins: B1, B2, B3, B5, B6, B7, B9, and B12. They are linked by one important characteristic: they function as coenzymes—tiny helpers without which hundreds of enzymes in the body would not be able to work.
In simple terms, B-complex vitamins help convert food into energy, form DNA, keep the nervous system in good condition, and produce red blood cells (Kennedy, 2016).
Because they are water-soluble, the body generally does not store them (with minor exceptions) and excretes the excess through urine. This means you must replenish them continuously, and the risk of vitamin B toxicity for most of them is low. However, it is important to note that a deficiency in one or more B vitamins still occurs relatively frequently, even in developed countries (Kennedy, 2016).
Just for reference: Aside from B vitamins, vitamin C is also classified as a water-soluble vitamin. In contrast, vitamin D, vitamin E, K, and A are fat-soluble vitamins.
What are the benefits of vitamin B?
The effects of vitamin B depend on the specific vitamins within the group. According to EFSA-approved health claims, B vitamins collectively contribute to:
- Normal energy-yielding metabolism (B1, B2, B3, B5, B6, B7, B12), i.e., converting food into usable energy
- Reduction of tiredness and fatigue (B2, B3, B5, B6, B9, B12)
- Normal functioning of the nervous system (B1, B2, B3, B6, B7, B12) and psychological function (B1, B3, B6, B7, B9, B12)
- Normal red blood cell formation (B6, B9, B12)
- Maintenance of normal skin, mucous membranes, and hair (B2, B3, B7)
Vitamin B for energy and fatigue
One of the most common reasons people reach for vitamin B is fatigue. And in a way, it makes sense: every vitamin B acts as a cofactor in energy metabolism, although it provides no energy itself.
Clinical studies show that in healthy individuals, a B-complex supplement reduced feelings of fatigue within 28 days (Lee et al., 2023). Crucially, however, the greatest benefits from supplementation are seen in those suffering from a dietary deficiency.
Vitamin B, stress, and mental well-being
B-complex vitamins are involved in the synthesis of neurotransmitters—the chemical messengers in the brain. In a meta-analysis of randomised trials, Young et al. (2019) observed lower perceived stress and improved subjective feelings of fatigue.
Studies have also noted improvements in perceived stress and mood when supplementing with higher doses of B vitamins (Kennedy et al., 2010). It is not a "happy pill," but rather support for the nervous system—specifically when it is lacking B vitamins from the diet.
Overview of B vitamins: Who does what?
Each B vitamin has its own role. For quick reference, we have summarised them in the table below. And since you often ask where vitamin B is found (and obtaining nutrients through diet should be the primary way to get them), we have also listed the main food sources.
Vitamin | Function in the body (EFSA claims) | Where to find it |
B1 (thiamin) | Normal energy metabolism, heart and nervous system function | Whole grains, pork, pulses |
B2 (riboflavin) | Reduction of fatigue, normal nervous system function, maintenance of skin, mucous membranes, vision, protection against oxidative stress | Dairy, eggs, almonds |
B3 (niacin) | Normal psychological function, reduction of fatigue, maintenance of skin and mucous membranes | Meat, fish, peanuts, whole grains |
B5 (pantothenic acid) | Normal energy metabolism, mental performance, synthesis of certain neurotransmitters | Organ meats, avocado, eggs, widely in foods |
B6 (pyridoxine) | Regulation of hormonal activity, red blood cell formation, nervous system function | Fish, poultry, bananas, potatoes |
B7 (biotin) | Maintenance of normal hair and skin, energy metabolism | Egg yolk, nuts, yeast |
B9 (folic acid / folate) | Maternal tissue growth during pregnancy, blood formation, psychological function | Leafy greens, pulses, broccoli |
B12 (cobalamin) | Red blood cell formation, nervous system function, reduction of fatigue | Animal sources only: meat, fish, eggs, milk |
However, it is worth noting that B vitamins are heat-sensitive and leach into water during cooking, causing some loss (Hrubša et al., 2022). Furthermore, you cannot reliably obtain vitamin B12 from plant-based sources. This is why supplements are most beneficial for at-risk groups.
B-complex or individual vitamins?
A B-complex (often searched for as vitamin B complex) is a food supplement that contains all eight B vitamins together. Why does this make sense? Because these vitamins work synergistically.
For example, B6, B9, and B12 work together to manage the conversion of homocysteine—an amino acid whose high levels are linked to health risks (Han et al., 2025).
In his review, Kennedy argues that it makes sense to supplement the entire B group at once, rather than just selected vitamins (Kennedy, 2016).
When should you reach for a specific B vitamin? When addressing a confirmed deficiency, typically vitamin B12 in vegans or folic acid when planning pregnancy. For general daily energy and nerve support, a high-quality B-complex is more practical.
Among B-complexes, you will also find products with enhanced B-vitamin content—higher doses than the basic daily requirement. These are suitable if you want stronger support for energy metabolism and the nervous system, or if you have higher physiological demands (sports, stress, restrictive diet).
However, even here, more does not automatically mean better—for some B vitamins, it is worth sticking to the recommended dosage (see the Safety section below).
Vitamin B12: A common problem for vegans and seniors
Vitamin B12 (cobalamin) is unique for several reasons. Unlike other B vitamins, it is stored in the liver and is found only in animal-based foods: meat, fish, eggs, and dairy products. This is why it is one of the most common nutrient deficiencies, especially among vegans and vegetarians.
Review studies report a vitamin B12 deficiency in 5 to 52% of vegans and 6 to 14% of vegetarians (Niklewicz et al., 2024). Data directly from the Czech Republic confirms this: among vegans who did not supplement with B12, a deficiency was proven in 15%, and the risk of low levels was more than four times higher compared to those who did supplement (Selinger et al., 2019).
The second at-risk group are seniors, whose absorption of B12 from food is impaired due to reduced stomach acid production, atrophic gastritis, or medication.
B12 forms and dosage
In supplements, you will encounter cyanocobalamin (stable and the most affordable) and active forms like methylcobalamin and adenosylcobalamin.
- For people with a mild deficiency, it has been shown that a daily dose of about 50 µg is more effective than one large weekly dose, as large single doses are absorbed less efficiently (Del Bo' et al., 2019).
- For vegans, a daily dose of 50 to 100 µg is usually recommended (Fernandes et al., 2024).
Folic acid (vitamin B9) and pregnancy
Folic acid is a form of vitamin B9 that is reliably and effectively absorbed by the body. It is best known for its role during pregnancy—specifically during the pre-conception period. Studies show that regular intake of 400 to 800 µg of folic acid daily around the time of conception reduces the risk of severe spinal and brain birth defects by up to 70–90% (US Preventive Services Task Force, 2017; Czeizel et al., 2013). This is why doctors recommend it to all women considering pregnancy—ideally starting before conception.
One point that is discussed less often: very high doses of folic acid can mask a vitamin B12 deficiency in blood tests. In other words, results might look normal even when they are not. Therefore, it makes sense to manage these two vitamins together. And this isn't the only role of folate—according to the EFSA, it also contributes to blood formation, normal psychological function, and the reduction of fatigue.
Biotin (vitamin B7) for hair: Fact or myth?
Biotin, or vitamin B7, is widely marketed as a miracle for hair and nails. However, in the case of biotin, marketing often outpaces available scientific evidence. Biotin does contribute to the maintenance of normal hair and skin (EFSA claim), but its supplementation only helps hair growth if you have a confirmed deficiency, which is rare in healthy people.
In people without a deficit, the evidence for improved hair growth is weak. If you are considering vitamin B for hair, view it as a supportive nutrient, not as a replacement for addressing the root cause.
Tip: We have a separate category for this topic: skin, complexion, and hair.
B-complex vitamins are also mentioned in relation to mucous membranes. Looking for vitamin B for mouth ulcers or cold sores? Riboflavin (B2) and niacin (B3) contribute to the maintenance of normal mucous membranes, and a deficiency can manifest in the oral mucosa. However, cold sores are caused by a virus, and mouth ulcers have multiple causes, so vitamin B is not a treatment here, but support.
How to choose and when to take vitamin B
Looking for the best vitamin B? Consider three factors: form, dosage, and your goals. The most practical and common forms are tablets and capsules. Both are comparably effective—what matters most is what is more comfortable for you to take and what dosage the product offers.
Caution: Always choose vitamin B for children in doses appropriate for their age and after consultation with a paediatrician.
When to take vitamin B?
Best in the morning with food. B vitamins support energy metabolism, and some people may find it harder to fall asleep after an evening dose. Taking it with a meal also improves tolerance.
A popular combination is magnesium and vitamin B, or specifically magnesium with vitamin B6, as B6 and magnesium complement each other in supporting nervous system function and reducing fatigue.
Also, zinc and vitamin B often appear together in complexes for immune and energy support.
Tip: Explore our category: calcium, magnesium, zinc.
Safety and precautions
Because B vitamins are water-soluble, vitamin B toxicity is unlikely for most of them; the body will excrete the excess. However, there are exceptions:
- Niacin (B3) in high doses can cause redness and burning of the skin, known as a 'flush'.
- Vitamin B6 in long-term high doses can lead to nerve damage (neuropathy).
- Folic acid in high doses can mask a vitamin B12 deficiency.
If you are taking medication, are pregnant, breastfeeding, or are dealing with a specific vitamin B deficiency, consult your doctor or pharmacist regarding the choice and dosage. Food supplements do not replace a varied diet or medical treatment, but where a gap in nutrition exists, they are a reliable way to bridge it.
How to choose the right vitamin B? Summary
Vitamin B is not one substance but a well-coordinated team of eight vitamins that sustain your energy, functioning nerves, healthy skin, and blood production. For daily support, a high-quality B-complex is most practical; for a specific deficiency, a targeted vitamin B12 or folic acid supplement is preferred. The form, dosage, and timing all play a role.
Choose your vitamin B on BodyWorld.eu according to your needs, whether it's a comprehensive B-complex for energy and nerves, B12 for vegans and seniors, or folic acid for family planning. If you are not currently lacking B-vitamins, explore our vitamins and minerals category. And don't forget to check our section for the latest deals and discounts.
Frequently Asked Questions (FAQ)
What are the benefits of vitamin B?
Vitamin B includes eight vitamins that contribute to normal energy metabolism, the reduction of fatigue and exhaustion, normal nervous system and psychological function, red blood cell formation, and the maintenance of normal skin, mucous membranes, and hair. It is most beneficial when correcting an actual deficiency.
Where is vitamin B found?
Vitamin B can be found in whole grains, pulses, meat, fish, eggs, dairy, leafy greens, nuts, and yeast. Vitamin B12 is an exception, as it is only found in animal products. Furthermore, cooking destroys some of the B vitamins in food.
What is the difference between a B-complex and individual vitamins?
A B-complex contains all eight B vitamins at once and is suitable for daily energy and nerve support because these vitamins work synergistically. Opt for a single vitamin when addressing a confirmed deficiency, typically B12 for vegans or folic acid during pregnancy.
Who is at risk of vitamin B12 deficiency?
Vitamin B12 is most commonly lacking in vegans and vegetarians, as it is found only in animal products, and in seniors, whose absorption decreases with age. These groups should supplement B12, ideally in a dose of 50 to 100 µg daily, and monitor levels via blood tests.
Does biotin help with hair growth?
Biotin (vitamin B7) contributes to the maintenance of normal hair, but its supplementation primarily aids hair growth only in cases of a genuine deficiency, which is rare in healthy people. In individuals without a deficit, evidence for improved growth is weak. Therefore, view it as a supportive nutrient rather than a guaranteed cure.
When should you take vitamin B—morning or evening?
Vitamin B is best taken in the morning with food. It supports energy metabolism, so an evening dose might interfere with falling asleep for sensitive individuals. Taking it with food also improves tolerability.
Can you overdose on vitamin B?
For most B vitamins, toxicity is unlikely because they are water-soluble and the body excretes the excess. Exceptions include high doses of niacin (skin flushing) and long-term high doses of vitamin B6 (risk of nerve damage). Do not exceed recommended dosages without consultation.
Can B vitamins replace a varied diet?
No. Vitamin B supplements are food supplements, not a meal replacement. A varied diet provides other essential nutrients and bioactive compounds. Supplements serve to bridge gaps, especially in at-risk groups like vegans, seniors, pregnant women, or those with restrictive eating habits.
Does vitamin B12 cause weight gain?
No, vitamin B12 does not cause weight gain itself—only a caloric surplus causes weight gain. This myth likely arose because B12 is administered to people with a deficiency who may have lost appetite and vitality; after supplementing, their energy and appetite return, which can lead to a slight weight increase. For an individual with sufficient B12 levels, supplementation will not affect weight.
Which B-complex is best?
There is no universally "best" B-complex—it depends on your needs. Check three things: composition (a high-quality complex contains all eight B vitamins), dosage (it should cover daily needs, but avoid excessive doses), and form (tablets and capsules are equally effective). Vegans and seniors should pay close attention to B12 content. You can also choose based on customer reviews and price-to-performance ratio.
What are the signs of vitamin B deficiency?
Deficiency in B vitamins can manifest as fatigue, exhaustion, low mood, irritability, tingling in the hands and feet, cracked corners of the mouth, mouth inflammation, and skin or hair problems. Symptoms vary depending on the specific vitamin, and they are often subtle. A blood test from your doctor is the only way to be certain — you cannot reliably diagnose a deficiency based on symptoms alone.
How long can I take B-complex?
B-complex can be taken long-term, even daily—B vitamins are water-soluble and the body does not store them (with exceptions). It is important to stick to recommended dosages: long-term high doses of B6 can lead to nerve damage, and high doses of niacin (B3) can cause skin flushing. If taking medication, or if pregnant or breastfeeding, consult your doctor regarding long-term use.
What is the fastest way to replenish vitamin B?
A varied diet is the foundation—you will find B vitamins in meat, whole grains, pulses, eggs, dairy, and leafy greens. When you need to replenish more quickly or are addressing a deficiency, taking a B-complex daily will help; because these vitamins are water-soluble, consistency is more important than a one-time high dose. For a confirmed B12 deficiency, higher doses and, in severe cases, injections are used, but always under medical supervision.
Does vitamin B help with mouth ulcers or cold sores?
Mouth ulcers and cold sores have different causes, and vitamin B affects them differently. Cold sores are caused by the herpes simplex virus—vitamin B will not cure or stop it. If you suffer from recurring cold sores, this is a matter for a doctor or antivirals, not a supplement.
Mouth ulcers are another chapter. Their causes vary—stress, minor injury, hormonal fluctuations, or precisely a deficiency of certain nutrients, including B vitamins. Riboflavin (B2) and niacin (B3) contribute to the maintenance of normal mucous membranes, and a deficiency can indeed manifest in the oral mucosa. If you are troubled by recurring ulcers and your diet isn't balanced, supplementing with B-complex may help—not as a cure, but by addressing a potential underlying cause.
In other words: Vitamin B for mouth ulcers makes sense as supportive nutrition where a deficiency is the underlying cause. Do not rely on it for cold sores.
MyVitamins Vitamin B 360 tablets
B-Complex 60 capsules
MyVitamins Vitamin B12 180 tablets
GreenDay B-Complex LIFE+ 60 capsules
B-Complex + Vitamin C 90 capsules