B vitamins: what do they actually do?
When we talk about B vitamins, we mean a family of eight water-soluble vitamins. They often work as a team – which is why they are usually sold together as a B complex. Because they are water-soluble, they are only stored in limited amounts (B12 is the exception), so the body needs regular top-ups.
What are the eight B vitamins?
Each B vitamin has a number and a name. Here is the whole family and what they mainly do in the body:
| Vitamin | Name | Key function |
|---|---|---|
| B1 | Thiamine | Normal energy metabolism and heart function |
| B2 | Riboflavin | Reduction of tiredness, normal skin and vision |
| B3 | Niacin | Energy metabolism and nervous system |
| B5 | Pantothenic acid | Normal mental performance |
| B6 | Pyridoxine | Hormone regulation and immune system |
| B7 | Biotin | Normal hair, skin and energy metabolism |
| B9 | Folate | Red blood cell formation and cell division |
| B12 | Cobalamin | Nervous system and red blood cells |
What do B vitamins do for energy?
The most common reason people take B vitamins is energy. There is a point to it: several B vitamins act as helpers (coenzymes) in the reactions that release energy from carbohydrates, fat and protein. According to EFSA, B2, B3, B6, B12 and folate contribute to a reduction of tiredness and fatigue.
Important to understand: B vitamins do not provide energy in themselves like a glass of juice. They help the cells' machinery do its job. If you are already well supplied, you won't notice an extra kick – the effect mainly applies when you are correcting a shortfall.
B-Komplex brings together all eight B vitamins in well-chosen forms – B12, B6 and folate contribute to normal energy metabolism and to a reduction of tiredness.
See current price »B vitamins for brain and mood
B6, B9 (folate) and B12 are needed for the nervous system and for normal psychological function. They are involved in producing neurotransmitters such as serotonin and dopamine, and they keep homocysteine levels in check – a substance researchers have linked to brain and vascular health. If you want to read more about B12 specifically, see our article on B12 deficiency and its symptoms.
Skin, hair and cells
Biotin (B7) contributes to normal hair and normal skin, which is why it often turns up in beauty products. Folate and B12 are needed for cell division and the formation of new blood cells – which makes them extra important during periods of rapid growth, such as pregnancy.
Where do you get B vitamins from?
Most B vitamins are found in a varied diet. Some good sources:
- Whole grains, oats and pulses – B1, B3, B6
- Eggs, milk and cheese – B2, B12, biotin
- Meat, fish and shellfish – B3, B6, B12
- Green leafy vegetables and lentils – folate
- Nuts and seeds – several B vitamins and minerals
B12 is an exception – it is found almost exclusively in animal foods. That is why vegans and vegetarians need a supplement or fortified foods. If you want to cover the full range, a B complex is a simple choice; see our guide to the best B complex and the whole energy collection.
Does everyone need a supplement?
No. If you eat a varied diet with both plant and animal products, you usually get what you need. A supplement is most justified for vegans, older adults, pregnant women and people with impaired absorption. If you are unsure about your levels, a blood test can give you an answer before you start. For anyone planning a baby, folate versus folic acid is especially relevant.
B vitamins and stress
During periods of stress and heavy load, the body's turnover of several nutrients increases, and the B vitamins are among them because they are central to energy production. That does not mean a supplement removes the stress, but running low on B vitamins while you are exhausted does not help your body recover.
Researchers have examined B vitamins and perceived stress in several studies. A 2019 review found that B-complex supplements could be linked to lower perceived stress in some groups, but the results vary and the need is individual. The foundation is always a varied diet and enough sleep.
Who has the most to gain from a supplement?
Most people get B vitamins through food, but some groups have higher needs or poorer absorption:
- Vegans and vegetarians – above all for B12
- Pregnant and breastfeeding women – increased need for folate and B12
- Older adults – lower stomach acid reduces B12 absorption
- People with high alcohol consumption – affects B1 and folate
- People with gut and digestive conditions that interfere with absorption
If you don't belong to any of these groups and eat a varied diet, you rarely need a supplement. If in doubt, a blood test gives you an answer before you start, and you don't have to guess.
How to keep the B vitamins in your food
B vitamins are water-soluble and sensitive to heat, light and long boiling. Some of the vitamins end up in the cooking water and get thrown away. With small adjustments, you keep more of the content in what you eat.
- Steam or stir-fry vegetables instead of boiling them for a long time
- Use the cooking water in soups and sauces
- Store whole grains and pulses in a dark, dry place
- Eat some greens raw, for example in a salad
Nobody needs to be perfect – the point is that a varied diet with green leaves, whole grains and animal sources covers the range of B vitamins without any fuss. A B complex works as a safety net when your diet is uneven.
Common myths about B vitamins
A few claims circulate around B vitamins that don't quite hold up. Here are three common ones.
- "More is always better." No – if you are already meeting your needs, extra doses rarely add anything, and some vitamins should not be taken in high doses for long periods.
- "B vitamins give you an energy kick." They support energy metabolism, but they don't work like caffeine or sugar. The effect is mainly noticeable when correcting a shortfall.
- "Yellow urine means the supplement is wasted." The yellow colour comes from riboflavin (B2) and is completely normal, not a sign that everything is flushed out unused.
In short: B vitamins are important but not magic. They do the most good when they fill an actual need, as part of an otherwise good diet.
Frequently asked questions
Do B vitamins give you more energy?
B2, B3, B6, B12 and folate contribute to normal energy metabolism and to a reduction of tiredness. But they work as helpers in the cells, not as a stimulant. You mainly notice an effect if you are correcting a shortfall – if you are already well supplied, extra supplements give no tangible kick or energy boost.
Can you get too much of the B vitamins?
Most B vitamins are water-soluble and any excess is excreted in the urine. Some, however, such as B6 in very high doses over a long period, can cause nerve problems. Stick to the recommended doses and don't exceed the manufacturer's directions without first consulting a pharmacist or doctor.
What time of day should you take B vitamins?
Morning, or with a meal early in the day, suits most people. B vitamins are involved in energy metabolism, and some people find them slightly energising – so late evening may be less suitable. Take them with food to reduce the risk of mild stomach discomfort.
What is the difference between individual B vitamins and a B complex?
A B complex contains all eight B vitamins in balanced amounts, which suits most people since the vitamins work together. Individual vitamins, for example high-dose B12, are used when you know that particular nutrient is lacking. For general coverage, a complex is usually the simplest choice.