B vitamins help your body release energy from the food you eat, but they are not fuel themselves. If your levels are already adequate, an extra B complex is unlikely to make you feel more energetic. If you are short of one, such as B12 on a vegan diet, correcting it can make a real difference to tiredness. This guide explains which B vitamins matter for energy, how B complex compares with B12 on its own, what doses are sensible in the UK and when tiredness needs a GP rather than a supplement.
TL;DR
- B vitamins act as helpers in the chemistry that turns carbohydrates, fats and protein into usable energy. They contain no calories and do not work like caffeine.
- A supplement tends to lift energy only when you are low in a B vitamin. Vegans, older adults and people on long-term metformin or acid-reducing tablets are the groups most often affected.
- B complex covers all eight B vitamins. A single B12 product makes more sense when B12 is the specific gap, for example on a vegan diet.
- Check the label for vitamin B6. The NHS advises no more than 10 mg a day from supplements unless a doctor has told you otherwise.
- Tiredness that lasts weeks, or comes with numbness, breathlessness or pallor, is a reason to see your GP before buying anything.
Table of Contents
- Do B vitamins actually give you energy?
- The eight B vitamins and what each does for energy
- B complex or B12 for energy?
- Who is most likely to be low?
- How much B vitamin do you need? A note on dosage
- Food first, supplement second
- What else could be draining your energy?
- Our view: transparency matters more than a bigger number
- Where our range fits
- When to see your GP
- FAQ
- Sources
Do B vitamins actually give you energy?
Not in the way a coffee or a sandwich does. The B vitamins do not supply calories. A registered dietitian quoted by Cleveland Clinic explains that most B vitamins help start the processes that turn carbohydrates, fats and proteins into a form of energy your body can use. Think of them as the workers on the production line rather than the raw material.
That is why the claims you see on UK labels are carefully worded. The NHS lists several B vitamins as helping to release energy from food. Thiamin (B1), for example, helps the body break down and release energy from food and keeps the nervous system healthy. Notice what that does not say: it does not say that taking more than you need produces more energy.
The practical consequence is simple:
- If you are deficient, the production line is slowed down. Topping up can restore it, and tiredness often improves.
- If you are not deficient, the line is already running. Extra B vitamins are mostly excreted, and you are unlikely to feel a lift.
Harvard Health makes a similar point about energy supplements in general. In its review of the best vitamins and minerals for energy, it notes that B12 injections probably will not raise energy unless you are deficient. The same logic applies to tablets and gummies.
The eight B vitamins and what each does for energy
The B group has eight members. Not all of them are equally relevant to tiredness, but they work as a connected system, so a shortfall in one can hold up the others. A review in the research literature describes this interdependence, which is one reason a broad B complex is sometimes preferred to a single vitamin when absorption is the problem (PubMed Central).
| Vitamin | Name | Role in energy and nerves | Typical food sources |
|---|---|---|---|
| B1 | Thiamin | Releases energy from food, supports nerves | Wholegrains, pork, pulses, fortified cereals |
| B2 | Riboflavin | Helps release energy from food, keeps skin and eyes healthy | Milk, eggs, mushrooms, fortified cereals |
| B3 | Niacin | Helps release energy from food | Meat, fish, wheat flour, eggs |
| B5 | Pantothenic acid | Helps release energy from food | Widely found in most foods |
| B6 | Pyridoxine | Helps the body use and store energy from protein and carbohydrate | Poultry, fish, potatoes, chickpeas, bananas |
| B7 | Biotin | Supports metabolism of fats, carbohydrates and protein | Eggs, nuts, some vegetables |
| B9 | Folate | Makes red blood cells, works alongside B12 | Green leafy vegetables, pulses, fortified cereals |
| B12 | Cobalamin | Makes red blood cells, supports nerves | Meat, fish, dairy, eggs, fortified foods |
The NHS page on B vitamins and folic acid sets out the functions and food sources vitamin by vitamin, and it is the best single reference to bookmark.
Which B vitamin is best for tiredness?
There is no single winner, and that is worth saying plainly. The two with the strongest link to fatigue when they run low are B12 and folate, because both are needed to make healthy red blood cells. When red blood cells are scarce, tissues receive less oxygen and you feel exhausted. The NHS describes B12 as being needed to make red blood cells, as it does for hydroxocobalamin, the form given to treat B12 deficiency anaemia.
The other B vitamins matter too, but outright deficiency of B1, B2, B3 or B5 is uncommon in the UK among people eating a varied diet.
B complex or B12 for energy?
This is the question behind most searches, and the answer depends on what you are trying to fix.
| B complex | B12 on its own | |
|---|---|---|
| What it contains | All eight B vitamins, usually in one dose | One vitamin |
| Best when | Your diet is patchy overall, or you have a reason for broad shortfalls | You know B12 is the gap, such as a vegan diet or a low blood result |
| Main watch-out | Check B6 and folic acid amounts on the label | Does not address other B vitamins |
| Evidence for energy | Helps only where there is a shortfall | Helps only where there is a shortfall |
If you eat no animal products, B12 is the one to think about first. The NHS notes that vitamin B12 is not found naturally in fruit, vegetables and grains, so vegans may not get enough of it. A reliable B12 source, whether fortified foods or a supplement, belongs in a vegan diet.
If your diet is varied and you eat meat, fish, eggs or dairy regularly, you most likely already get what you need, and a B complex adds little.
B complex versus a multivitamin
A multivitamin spreads a small amount of many nutrients, vitamins and minerals, into one product. A B complex concentrates on the B group, often at higher amounts than a multivitamin. Neither is a shortcut to energy. If you want a multivitamin for general cover, you do not also need a separate B complex, and doubling up is how people end up with more B6 than they intended.
Who is most likely to be low?
Deficiency is a medical issue, not just a lifestyle one. These groups come up repeatedly in UK guidance.
Vegans and some vegetarians
B12 comes from animal foods, so plant-based diets need fortified products or a supplement. A local NHS medicines optimisation guideline lists people on diets low in B12 without supplements as a high-risk group. The same document explains why it is easy to miss in younger adults: the liver stores B12 for a long time, so symptoms may appear years after intake falls. Once stores run down, eating a fortified cereal is rarely enough to correct a true deficiency, and treatment may need high-dose tablets or injections.
People on metformin or acid-reducing medicines
Long-term metformin (for type 2 diabetes) and proton pump inhibitors (for heartburn and reflux) are recognised causes of low B12. NHS guidance names them as risk factors, with metformin use of more than 12 months highlighted in the Harvard review above. If you have taken either for a year or more and feel unusually tired or notice tingling, raise it with your GP. Do not simply start a supplement and wait.
Older adults
Absorbing B12 from food gets harder with age. Harvard Health reports that around 6% of people aged 60 and over may be deficient, so it is worth asking about if you are in this group and persistently tired.
People with absorption problems
Conditions such as pernicious anaemia, an autoimmune cause of B12 malabsorption, will not be fixed by an over-the-counter gummy or capsule. A Scottish NHS clinical summary stresses that the vast majority of people with a low B12 result do not have pernicious anaemia, but it is an important diagnosis not to miss. This is a job for your GP, who can test and decide whether you need injections.
The same document also notes that serum B12 can dip during pregnancy and with some contraceptives without meaning tissue-level deficiency. A single low number is not automatically a diagnosis, which is another reason to let a clinician interpret it.
How much B vitamin do you need? A note on dosage
More is not better, and one B vitamin in particular deserves attention.
Vitamin B6: check the label
The NHS says adults need about 1.2 mg a day (women) or 1.4 mg a day (men), and advises against more than 10 mg of vitamin B6 a day in supplements unless a doctor tells you to. Taking 200 mg or more a day can cause peripheral neuropathy, a loss of feeling in the arms and legs. The effect of doses between 10 mg and 200 mg is unclear, so the NHS cannot say how long they might be taken safely.
In 2023 EFSA lowered its own safe upper level for adults to 12.5 mg a day, reflecting concern about nerve damage (EFSA dietary reference values). UK Department of Health guidance on food supplements also asks for an advisory statement on products containing higher amounts (Department of Health advisory statements). Some high-strength B complexes sit well above 10 mg, so read the amount in milligrams, not the marketing line.
Vitamin B12
Adults aged 19 to 64 need about 1.5 micrograms a day, and the NHS says taking 2 mg or less a day in supplements is unlikely to cause harm. That 2 mg is 2,000 micrograms, so you will see products with very large numbers on the label. Those numbers reflect how poorly B12 is absorbed at high doses, not a need for that quantity.
Folate and folic acid
Adults need about 200 micrograms of folate a day, according to the same NHS page. If you are pregnant or trying to conceive, the advice on folic acid is different and specific, so ask your midwife or GP rather than relying on a general B complex.
A simple dosage checklist
- Look for each B vitamin by name and the amount in mg or micrograms, not a blend total.
- Check B6 against the 10 mg a day NHS advice.
- Add up anything else you take: a multivitamin, fortified drinks and cereals all contribute.
- If you take prescribed medicines, ask a pharmacist before adding a supplement.
Food first, supplement second
The dietitian quoted by Cleveland Clinic is clear that B vitamins should ideally come from a varied, whole-food diet, which also brings fibre and antioxidants that a pill cannot replicate, with supplements acting as a safety net rather than a replacement for balanced eating. That fits UK guidance, which says most people can get what they need from their diet.
Practical ways to cover your B vitamins through food:
- Choose wholegrain bread, oats and brown rice for B1 and B3.
- Eat pulses, green vegetables and fortified cereals for folate.
- Use fortified plant milks, yeast extract spreads or fortified nutritional yeast for B12 if you avoid animal foods. Check the label for added B12.
- Include eggs, dairy or fish if you eat them: they are reliable B12 and B2 sources.
What else could be draining your energy?
Before reaching for a B complex, consider the more common explanations. Poor sleep, low iron, low vitamin D, a thyroid problem, stress, low mood and long hours are all common causes of persistent tiredness in UK adults. Harvard Health cautions that if you are not iron deficient there is no evidence taking iron for energy helps, and it can lead to overload. The lesson applies across the board: guessing at supplements can waste money and occasionally cause harm.
Two areas are worth looking at yourself first:
- Sleep. If you wake unrefreshed, no vitamin will compensate. Our guide to natural sleep aids in the UK looks at what the evidence does and does not support.
- Vitamin D. Low levels are common in UK winters. Read how vitamin D3 and K2 work together if that could apply to you.
Our view: transparency matters more than a bigger number
We make gummy vitamins at Vitgem, and we will be straightforward: we do not sell a B complex, and this article is not a nudge to buy one from us. What we do care about is the same thing that matters when you pick any B vitamin product: knowing exactly what you are swallowing.
That is how we build our own range. Every active ingredient and dose is printed on the label, with no proprietary blends hiding the amounts. The gummies are vegan and gelatin-free, four of the five are sugar-free, the range is batch-tested and it is made in a GMP-certified facility. We keep our claims within UK supplement rules and avoid promising more than the evidence supports.
On energy specifically, our view is cautious. Tiredness has many causes, and a label claim about energy-yielding metabolism is not a promise that you will feel different. If you have a diagnosed shortfall, follow your clinician. If you are guessing, start with sleep, food and a conversation with your GP or pharmacist, and choose any supplement whose label you can fully read.
— VITGEM
Where our range fits
If your tiredness is tied to poor sleep, stress or low vitamin D rather than a B vitamin gap, these are the relevant products. Each bottle is £12.99 one-off, and UK delivery is £2.49 (free on orders over £20).
- Sleep Gummies, Night-Time Formula, for the nights you struggle to wind down.
- Ashwagandha Gummies with Lion’s Mane and Ginkgo, for people whose low energy is bound up with stress and mental fog.
- Vitamin D3 K2 Gummies, 4000 IU, for the darker months.
You can see everything on the full gummies collection, and our Subscribe & Save option is there if you want a regular delivery. If you wonder whether a gummy can deliver what a tablet does, we cover that in Do gummy vitamins work?.
When to see your GP
Book an appointment instead of self-treating if you notice any of the following:
- Tiredness that lasts more than a few weeks with no clear cause.
- Tingling, pins and needles or numbness in the hands or feet, especially if you take B6 supplements.
- Pale skin, breathlessness, a sore tongue or noticeable memory and concentration changes.
- You take metformin or a proton pump inhibitor and have done so for over a year.
- You follow a vegan diet and have never had your B12 checked or supplemented.
Your GP can test B12 and folate and look for other causes. The local NHS guideline mentioned above treats a B12 level of 300 ng/L or more as making deficiency very unlikely, and the pathway for lower results involves further checks rather than automatic supplements. If B12 deficiency is confirmed, treatment is usually prescribed.
FAQ
Do B vitamins actually give you energy?
Not directly. They help your body convert food into energy but have no calories of their own. A supplement is most likely to help if you are short of a B vitamin, and unlikely to change much if you are not.
Should I take B complex or B12 for energy?
Take B12 alone if B12 is the known gap, such as on a vegan diet or after a low blood result from your GP. A B complex is a reasonable choice if your diet is limited across several B vitamins. Either way, check the B6 amount against the NHS limit of 10 mg a day.
How much B complex should I take daily?
Follow the label, and check each vitamin rather than the product as a whole. The NHS advises no more than 10 mg of B6 daily from supplements without medical advice, and says 2 mg or less of B12 a day is unlikely to cause harm. Ask a pharmacist if you take prescribed medicines.
Can I get enough B vitamins from food?
Most people eating a varied diet can. Vegans are the main exception for B12 and need fortified foods or a supplement. Older adults and people on long-term metformin or acid-reducing medicines may also need their levels checked.
Sources
- NHS: B vitamins and folic acid
- NHS: About hydroxocobalamin
- Cleveland Clinic: B vitamins, types, benefits and side effects
- Harvard Health: Best vitamins and minerals for energy
- PubMed Central: B vitamin review
- NHS guideline for the management of vitamin B12 deficiency in over 16s
- Right Decisions (NHS Scotland): Vitamin B12 treatment
- EFSA: Dietary reference values
- Department of Health: Food supplements advisory statements