Vitamins for Tiredness and Fatigue: What Actually Helps (UK Guide)

By the GUUDIES Editorial Team · Updated 25 October 2026 · Health claims checked against the GB Nutrition and Health Claims Register (sources below).

Disclosure: GUUDIES makes a daily gummy supplement, so we have an interest here. We have kept to what UK guidance and the evidence say, and linked our sources.

Which vitamins help with tiredness and fatigue? In the UK, the nutrients authorised to say they "contribute to the reduction of tiredness and fatigue" are vitamin B2, niacin (B3), pantothenic acid (B5), vitamin B6, folate, vitamin B12, vitamin C, iron and magnesium. They help most when you are actually short of them, so if you have been tired for weeks without a clear reason, a GP blood test comes before any supplement.

Feeling tired all the time is one of the most common reasons people see a GP. Often the cause is sleep, stress or lifestyle. Sometimes it is a nutrient shortfall, such as low iron or low vitamin B12, that a simple test can find. This guide covers both: what to rule out, and which vitamins for tiredness and fatigue are worth considering.

Why Am I Tired All the Time, Even With Enough Sleep?

The NHS lists the usual causes as poor sleep, an unhealthy diet or little exercise, stress, depression, big life events, hormonal changes such as pregnancy or the menopause, and illnesses such as glandular fever or COVID-19. Conditions such as iron deficiency anaemia and thyroid problems can also cause constant tiredness.

That is why no supplement is a fix for every kind of tiredness. A vitamin can only help with the part of the problem that comes from not getting enough of that vitamin.

Which Vitamins Help With Tiredness and Fatigue?

Under GB law, a supplement can only say a nutrient reduces tiredness if that claim is on the GB Nutrition and Health Claims Register. These are the ones that qualify:

Nutrient	Authorised claim	Good food sources
Vitamin B12	Contributes to the reduction of tiredness and fatigue	Meat, fish, eggs, dairy, fortified foods
Iron	Contributes to the reduction of tiredness and fatigue	Red meat, pulses, fortified cereals, dark green veg
Folate	Contributes to the reduction of tiredness and fatigue	Leafy greens, chickpeas, fortified cereals
Vitamins B2, B3, B5, B6	Contribute to the reduction of tiredness and fatigue	Wholegrains, meat, eggs, dairy
Vitamin C	Contributes to the reduction of tiredness and fatigue	Citrus, peppers, berries, broccoli
Magnesium	Contributes to the reduction of tiredness and fatigue	Nuts, seeds, wholegrains, leafy greens

Vitamin D is not on this list. It contributes to the normal function of the immune system and normal muscle function, and the NHS asks everyone in the UK to consider it from October to March, but it has no authorised tiredness claim.

Can Low Iron Make You Tired?

Yes. The NHS lists lack of energy, shortness of breath, noticeable heartbeats and pale skin as symptoms of iron deficiency anaemia. It is more common in people with heavy periods, during pregnancy, and in people who eat little or no meat.

Do not start high-dose iron on a hunch. Too much iron can be harmful, so get a blood test first and take iron only if a GP or pharmacist advises it.

Can Low Vitamin B12 Cause Fatigue?

Yes. Extreme tiredness is one of the main symptoms the NHS lists for vitamin B12 or folate deficiency anaemia. People at higher risk include vegans, older adults, and people taking certain medicines such as metformin or long-term acid reflux treatments. B12 is found almost only in animal foods, so anyone on a plant-based diet needs fortified foods or a supplement.

What About Vitamin D and Tiredness?

Between October and early March, UK sunlight is too weak for your skin to make vitamin D, so the NHS advises everyone to consider 10 micrograms a day over autumn and winter, and not to take more than 100 micrograms a day. Low vitamin D can cause muscle aches and weakness, and taking it in winter is sensible for most people. Just do not expect it to work like a tiredness remedy, because that is not what it is authorised for.

Do Energy Supplements With Caffeine Help?

Caffeine can make you feel more alert for a few hours, but it does not fix the reason you are tired, and caffeine late in the day can make sleep worse. If you rely on it to get through every afternoon, that is a signal to look at sleep, diet and the causes above.

When Should You See a GP About Tiredness?

The NHS advises seeing a GP if:

• you have felt tired for a few weeks and are not sure why
• your tiredness affects your daily life
• you also have unexplained weight loss or mood changes
• you have been told you gasp, snort or choke in your sleep

A GP may arrange blood tests to check for anaemia, diabetes or thyroid problems. That gives you a clear answer before you spend money on supplements.

How to Choose a Supplement for Tiredness

• Test before you treat. Iron especially should be based on a blood test.
• Look for the authorised nutrients. B12, folate, the other B vitamins and vitamin C at sensible doses.
• Check the %NRV. Around 100% of the nutrient reference value is plenty for most people; megadoses add cost, not benefit.
• Read the claims. The legal wording is "contributes to the reduction of tiredness and fatigue". Anything louder is marketing.
• Pick something you will actually take. A daily habit you keep matters more than a perfect formula you forget.

Where GUUDIES Fits

The Daily Greens+ gummy, one of the six gummies in each GUUDIES daily pouch, contains vitamin C (80mg, 100% NRV), vitamin B6 (1.7mg), niacin (14mg), pantothenic acid (5mg) and vitamin B12 (24µg). Vitamin C, vitamin B6, niacin, pantothenic acid and vitamin B12 contribute to the reduction of tiredness and fatigue. It also provides vitamin D3 at 20µg, which contributes to the normal function of the immune system. There is no caffeine in any of the six gummies, and GUUDIES does not contain iron.

Daily Greens+ is vegan. Five of the six gummies in the pouch are vegan; the Marine Collagen gummy contains fish collagen. See the full doses on our B vitamins page or see what is in a GUUDIES pouch.

Common Questions

What is the best vitamin for tiredness and fatigue?
There is no single best one. Vitamin B12, folate, iron, vitamin C, magnesium and the B vitamins B2, B3, B5 and B6 all have an authorised claim. The one that helps you is the one you are short of, which a blood test can show.

Does vitamin D help with tiredness?
Vitamin D has no authorised tiredness claim. It contributes to normal immune and muscle function, and the NHS advises considering 10 micrograms a day from October to March.

How long do vitamins for tiredness take to work?
If you are deficient, it usually takes a few weeks of consistent use to notice a difference, and correcting low iron or B12 can take longer. If you are not deficient, extra vitamins are unlikely to change how tired you feel.

Can I take iron without a blood test?
It is better not to. Too much iron can be harmful, so check your levels with a GP first.

When should I worry about being tired all the time?
See a GP if you have been tired for a few weeks without a clear reason, if it affects daily life, or if you also have weight loss or mood changes.

Are energy gummies the same as vitamins for tiredness?
Not always. Many energy products rely on caffeine. Check the label for authorised nutrients such as B vitamins and vitamin C instead.

Sources

• NHS, Tiredness and fatigue: nhs.uk
• NHS, Iron deficiency anaemia: nhs.uk
• NHS, Vitamin B12 or folate deficiency anaemia: nhs.uk
• NHS, Vitamin D: nhs.uk
• GB Nutrition and Health Claims Register: gov.uk

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