Energy Supplements UK: Which Ones Work, With or Without Caffeine?
Energy supplements compared: caffeine, B vitamins, iron, magnesium, CoQ10 and mushrooms. Which have UK-authorised claims, what the evidence says, and how to choose.
By the GUUDIES Editorial Team · Updated 26 October 2026 · Health claims checked against the GB Nutrition and Health Claims Register (sources below).
Disclosure: GUUDIES makes a daily gummy supplement with no caffeine, so we have an interest here. We have kept to what UK guidance and the evidence say.
Which energy supplements actually work? There are two kinds. Caffeine products make you feel more alert for a few hours. Nutrient supplements, such as B vitamins, vitamin C, iron and magnesium, are authorised in the UK to say they contribute to normal energy-yielding metabolism or the reduction of tiredness and fatigue, and they help most when you are short of them. Neither fixes poor sleep, and constant tiredness is worth a GP check first.
Stimulant or Nutrient: Two Kinds of Energy Supplement
Stimulants such as caffeine, guarana and green tea extract act on your nervous system. You feel the effect within an hour, it wears off within a few, and regular users build tolerance.
Nutrients such as the B vitamins, iron and magnesium are part of how your body turns food into energy. They do not give an instant lift. If you are low in one of them, topping it up can make a real difference over a few weeks. If you are not, extra is unlikely to change how you feel.
Energy Supplements Compared
| Ingredient | Authorised GB claim | What to know |
|---|---|---|
| Vitamin B12 | Contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue | Vegans and older adults are more likely to be short |
| Other B vitamins (B1, B2, B3, B5, B6, biotin, folate) | Energy-yielding metabolism and/or reduction of tiredness and fatigue (varies by vitamin) | Most people get enough from a varied diet |
| Iron | Contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue | Only take iron if a blood test shows you need it |
| Magnesium | Contributes to the reduction of tiredness and fatigue | High doses can loosen stools |
| Vitamin C | Contributes to the reduction of tiredness and fatigue | NHS: adults need 40mg a day |
| Iodine | Contributes to normal energy-yielding metabolism | Found in dairy, fish and eggs; avoid very high doses |
| Caffeine | No authorised claim for energy | Short-lived alertness; can disturb sleep |
| CoQ10 | None | Body makes its own; trial evidence on tiredness is limited |
| Cordyceps and other mushrooms | None | Small, mixed studies |
Do B Vitamins Give You Energy?
B vitamins do not contain energy, but your body needs them to release energy from food. That is why several are authorised to say they contribute to normal energy-yielding metabolism. Low vitamin B12 is a known cause of extreme tiredness: the NHS lists it as a main symptom of B12 or folate deficiency anaemia. People at higher risk include vegans, older adults and people on certain medicines such as metformin. B12 comes almost only from animal foods, so plant-based eaters need fortified foods or a supplement.
Is Caffeine a Good Energy Supplement?
Caffeine makes most people feel more alert for a few hours. It does not fix the reason you are tired, and caffeine in the afternoon can make it harder to sleep, which feeds the cycle. The NHS advises no more than 200mg a day in pregnancy (about two mugs of instant coffee). Check the label of any "energy" gummy or capsule: many contain as much caffeine as a coffee, and it adds to what you already drink.
Can Low Iron Make You Tired?
Yes. Tiredness and lack of energy are the main symptoms of iron deficiency anaemia, which is more common with heavy periods, in pregnancy and in people who eat little meat. Do not start iron on a hunch, as too much can be harmful. A GP blood test will tell you whether you need it.
What About Vitamin D?
The NHS advises everyone in the UK to consider 10 micrograms of vitamin D a day from October to March. Vitamin D contributes to normal muscle function and the normal function of the immune system, but it has no authorised energy or tiredness claim, so be wary of products that sell it as an energy fix.
Do Mushroom and Adaptogen Energy Supplements Work?
Cordyceps, rhodiola and similar ingredients appear in many energy products. Some small studies look promising, but the results are mixed, and none of these ingredients has an authorised energy claim in Great Britain. Treat them as optional extras, not the main reason to buy a product.
When to See a GP
The NHS advises seeing a GP if you have felt tired for a few weeks without knowing why, if it affects daily life, or if you also have weight loss or mood changes. Blood tests can check for anaemia, thyroid problems and diabetes before you spend money on supplements.
How to Choose an Energy Supplement
- Decide what you want. A quick lift (caffeine) and filling a nutrient gap (vitamins and minerals) are different jobs.
- Look for authorised nutrients. B12, the other B vitamins, vitamin C, magnesium and iodine at sensible doses.
- Check the caffeine. Add it to your coffee and tea for the day.
- Check the %NRV. Around 100% is enough for most people; megadoses add cost, not benefit.
- Read the claims. "Contributes to the reduction of tiredness and fatigue" is the legal wording. "All-day energy" is marketing.
Where GUUDIES Fits
None of the six gummies in the GUUDIES daily pouch contains caffeine. The Daily Greens+ gummy provides vitamin B12 (24µg), vitamin B6 (1.7mg), niacin (14mg), pantothenic acid (5mg) and vitamin C (80mg), which contribute to the reduction of tiredness and fatigue, plus vitamin D3 at 20µg. The pouch also includes a Mushroom Mix gummy; mushrooms have no authorised energy claim. GUUDIES does not contain iron. Daily Greens+ is vegan; five of the six gummies in the pouch are vegan, and 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 supplement for energy?
There is no single best one. If you are short of vitamin B12, iron or another B vitamin, correcting that helps most. Caffeine gives short-term alertness but does not fix the cause of tiredness.
Do energy supplements without caffeine work?
Nutrients such as B vitamins, vitamin C and magnesium are authorised to say they contribute to the reduction of tiredness and fatigue. They help most when you are low in them, over a few weeks rather than minutes.
How long do energy vitamins take to work?
If you are deficient, usually a few weeks of daily use. Correcting low iron or B12 can take longer.
Are energy gummies safe?
Most are, at label doses. Check the caffeine content, avoid doubling up on the same vitamins, and ask your GP or pharmacist if you are pregnant or take medication.
Does vitamin D give you energy?
Vitamin D has no authorised energy or tiredness claim, but the NHS advises considering it from October to March for other reasons.
Sources
- NHS, Tiredness and fatigue: nhs.uk
- NHS, Vitamin B12 or folate deficiency anaemia: nhs.uk
- NHS, Iron deficiency anaemia: nhs.uk
- NHS, Vitamin D: nhs.uk
- NHS, Foods to avoid in pregnancy (caffeine): nhs.uk
- GB Nutrition and Health Claims Register: gov.uk
Related Reading
Tired All the Time? Vitamins for Tiredness · Focus Gummies · Vitamin B12 Gummies for Vegans · See our full ingredient list
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