Quick answer
- Ten nutrients may claim to contribute to the normal function of the immune system (UK and EU): vitamins A, B6, B12, C, D, folate, and copper, iron, selenium and zinc, from 15% of the NRV per daily dose.
- In winter the most common gap is vitamin D: the NHS advises 10 µg a day in autumn and winter. It corrects a shortfall; it has not been shown to prevent colds overall.
- For colds, zinc started early may shorten them by about two days and daily vitamin C by about 8% in adults, on modest evidence.
- Echinacea, elderberry, propolis and probiotics have no authorised claim; the evidence for echinacea is weak.
Key numbers
- Nutrients with an authorised immune claim (UK and EU)
- 10
- A, B6, B12, C, D, folate, copper, iron, selenium, zinc.
- Minimum for the claim
- 15% NRV per daily dose
- For vitamin C that is 12 mg.
- UK vitamin D advice (NHS)
- 10 µg/day in autumn and winter
- UK maximum zinc from supplements (NHS)
- 25 mg/day
- UK vitamin C (NHS)
- Under 1,000 mg/day unlikely to cause harm
- Authorised claims for echinacea, elderberry, propolis
- None
What these terms mean: NRV upper levels (NHS, EFSA) maximum levels by country daily dose
How to choose
- Look for the vitamin or mineral behind the claim on the back of the pack; herbs on the front don't carry an authorised claim.
- In autumn and winter, a daily vitamin D supplement of 10 µg is the NHS advice for most people.
- For a cold, zinc lozenges started within a day of the first symptoms are the option with the most support; stop after a few days.
- Add up zinc and vitamin C from every product you take, including multivitamins.
- Skip "immune shots" and gummies if the label shows small amounts of vitamins with added sugar.
Which supplement for which winter question
| Question | Option with the best support | What to expect |
|---|---|---|
| Not much sun between October and March | Vitamin D, 10 µg a day | Corrects a shortfall; no clear protection against colds overall |
| Cold just started | Zinc lozenges, started early | May shorten a cold by about 2 days; low certainty |
| Colds every winter | Daily vitamin C | Doesn’t prevent them; shortens them by about 8% in adults |
| Hard physical training in the cold | Vitamin C | Fewer colds in trials of marathon runners and soldiers; an authorised claim at 200 mg extra a day |
| Want a “natural” option | Echinacea, elderberry, propolis | No authorised claim; weak or little evidence |
| Gut and immunity | Specific probiotic strains | May mean fewer respiratory infections; low certainty and strain-specific |
Read immune support supplements in winter for the trials behind each row and how little a label needs to say “immune”.
The table below ranks every ingredient in our goal finder for immune support by strength of evidence.
Ingredients for this goal, by strength of evidence
| Ingredient | Evidence | Authorised claim (UK/EU) | What the evidence shows |
|---|---|---|---|
| Vitamin D3 | Strong | Yes | Authorised claim (UK & EU); deficiency is common in winter. |
| Zinc | Strong | Yes | Authorised claim (UK & EU); lozenges may shorten colds. |
| Vitamin C | Strong | Yes | Authorised claim (UK & EU); may slightly shorten colds. |
| Vitamin B6 | Limited | Yes | Authorised immune claim (UK & EU); only if low. |
| Vitamin B12 | Limited | Yes | Authorised immune claim (UK & EU); only if low. |
| Folate | Limited | Yes | Authorised immune claim (UK & EU); only if low. |
| Iron | Limited | Yes (only if deficient) | Authorised immune claim (UK & EU); only if deficient. |
| Probiotic cultures | Limited | No | Some strains reduce respiratory infections a little. |
What the label may legally claim
Authorised claims (GB and EU registers)
- Vitamins A, B6, B12, C, D and folate, and copper, iron, selenium and zinc contribute to the normal function of the immune system (from 15% NRV per daily dose)
- Vitamin C contributes to maintain the normal function of the immune system during and after intense physical exercise (200 mg a day on top of the normal intake)
- Vitamin D contributes to the normal function of the immune system in children
Not authorised in GB or the EU
- Boosting, stimulating or strengthening the immune system
- Preventing colds or flu
- Any immune claim for echinacea, elderberry, propolis, royal jelly or probiotics
How health claims work (UK & EU): health claims claims on hold (plants)
Products we have checked
Label data checked by NutriMetrics for products sold in Spain and Germany. UK product checks are next. Sorted alphabetically, not ranked.
| Product | Per daily dose | Sold in | Label |
|---|---|---|---|
| Lactoflora (Stada) Lactoflora Restore1 capsule a day after a meal | Probiotic cultures: 4 bn CFU · 4 strains (NCFM, Lpc-37, Bl-04, Bi-07) | Spain | Source |
| OMNi-BiOTiC OMNi-BiOTiC 61 sachet (3 g) a day | Probiotic cultures: 3 bn CFU | Germany (not yet confirmed) | Source |
| Solgar Ester-C Plus 1000 mg1 tablet a day | Vitamin C: 1,000 mg | Spain · Germany (not yet confirmed) | Source |
| Solgar Gentle Iron 25 mg1 capsule a day | Iron: 25 mg · bisglycinate (Ferrochel) | Spain (not yet confirmed) · Germany (not yet confirmed) | Source |
| Solgar Vitamin D3 2200 IU (55 µg)1 capsule a day | Vitamin D3: 55 µg | Spain (not yet confirmed) · Germany (not yet confirmed) | Source |
| Solgar Vitamina B12 1000 µg masticable1 chewable a day | Vitamin B12: 1,000 µg · cyanocobalamin | Spain | Source |
| Solgar Zinc Picolinate 22 mg1 tablet a day with food | Zinc: 22 mg · picolinate | Spain · Germany (not yet confirmed) | Source |
| Vita Natura Vitamin D3+K2 1000 IE Tropfen1 drop a day | Vitamin D3: 25 µg | Germany | Source |
| Yes Vegan! Vitamin B Komplex hochdosiert1 capsule a day Label only partly captured | Vitamin B12: 500 µg Folate: 400 µg Vitamin B6: 2.8 mg | Germany | Source |
Who should be careful
- Zinc: more than 25 mg a day for a long time can cause copper deficiency. Don't keep taking high-dose "cold" products for weeks.
- Vitamin A: avoid supplements containing vitamin A in pregnancy.
- Echinacea: the European Medicines Agency's herbal monograph says not to use it with an allergy to the daisy family, and does not recommend it with autoimmune diseases, immune deficiencies or immunosuppression.
- Iron: only take it if a blood test shows you need it.
FAQ
What is the best supplement for the immune system?
No supplement has been shown to boost a healthy immune system. If you are low in vitamin D in winter, a daily vitamin D supplement corrects that; the NHS advises 10 µg a day in autumn and winter. For colds, zinc lozenges started early may shorten them by about two days.
Which vitamins support the immune system?
Vitamins A, B6, B12, C, D and folate have an authorised claim for the normal function of the immune system, as do the minerals copper, iron, selenium and zinc. A product needs 15% of the NRV of one of them per daily dose to use the claim.
Are immune complexes with echinacea worth it?
Echinacea has no authorised claim, and a Cochrane review found only a weak, uncertain effect on colds. If a complex works at all, it is likely because of the vitamin C or zinc in it, which you can buy on their own.
Sources
- European Commission — EU Register of nutrition and health claims
- DHSC — Great Britain nutrition and health claims (NHC) register
- Commission Regulation (EU) No 432/2012 — list of permitted health claims
- Commission Regulation (EU) 2016/1389 — vitamin D and the immune system in children
- NHS — Vitamin D
- NHS — Others (magnesium, selenium, zinc)
- NHS — Vitamin C
- European Medicines Agency — EU herbal monograph on Echinacea purpurea herb
- Jolliffe DA et al. Vitamin D supplementation to prevent acute respiratory infections. Lancet Diabetes Endocrinol, 2025
- Karsch-Völk M et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev, 2014
- Zhao Y et al. Probiotics for preventing acute upper respiratory tract infections. Cochrane Database Syst Rev, 2022
Information only, not medical advice. No product on this page is a paid placement.