Immune Support Supplements UK: Which Vitamins Actually Matter This Winter

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, so we have an interest here. We have kept to what the evidence and UK guidance actually say, and linked our sources.

Which immune support supplements are worth taking in the UK? The nutrients with UK-authorised immune claims are vitamin D, vitamin C, zinc, vitamin A, vitamin B6, vitamin B12, folate, copper, iron and selenium, each of which contributes to the normal function of the immune system. Of these, vitamin D is the one the NHS asks everyone in the UK to consider between October and March, so it is the sensible place to start.

Shelves fill up with "immune" products every autumn. Most of what they promise cannot legally be claimed in the UK, and some popular ingredients, such as elderberry and echinacea, have no authorised immune claim at all. Below is what the authorised list covers, what the research says about the big names, and how to choose without overspending.

What Are the Best Vitamins for the Immune System?

In Great Britain, a supplement can only say a nutrient supports the immune system if that claim is on the GB Nutrition and Health Claims Register. The vitamins and minerals with an authorised claim that they "contribute to the normal function of the immune system" are:

• Vitamin D, the one most people in the UK fall short on in winter
• Vitamin C
• Zinc
• Vitamin A
• Vitamins B6 and B12, and folate
• Copper, iron and selenium

If a product promises to "boost" or "strengthen" immunity, that wording goes beyond what is authorised. The honest version is that these nutrients contribute to normal immune function, and topping up matters most if your diet or sunlight exposure leaves you short.

Why Is Vitamin D the Priority in Autumn and Winter?

Between October and early March the sun in the UK is not strong enough for your skin to make vitamin D. That is why the NHS advises everyone to consider a daily supplement of 10 micrograms (400 IU) through autumn and winter, and some groups, including people who are rarely outdoors or who cover most of their skin, to consider it all year. The NHS also advises adults not to take more than 100 micrograms a day.

Vitamin D contributes to the normal function of the immune system. Starting in early autumn rather than waiting until you feel run down is simply following the NHS timing.

Does Vitamin C Stop You Catching Colds?

Not for most people. A Cochrane review of 29 trials found that taking vitamin C regularly did not reduce how often the general population caught colds. It was linked to slightly shorter colds, and people under heavy physical stress, such as marathon runners, saw fewer colds. Vitamin C still contributes to the normal function of the immune system, so getting enough matters, but megadoses are not a shield.

Does Zinc Help the Immune System?

Zinc contributes to the normal function of the immune system and is found in meat, shellfish, seeds and pulses. The research on zinc lozenges for treating colds is less clear than headlines suggest: a 2024 Cochrane review rated the evidence on duration as low certainty. More is not better either. High doses of zinc taken for long periods can lower copper levels, which is why balanced formulas pair the two.

Do Elderberry Gummies Work?

Elderberry gummies are popular, but elderberry has no authorised immune health claim in Great Britain, and systematic reviews have found the trial evidence too small and mixed to draw firm conclusions. If you enjoy them, check what else is in the gummy: many contain vitamin C or zinc, and those are the ingredients that carry the authorised claim. Elderberry should only ever be eaten cooked or as a prepared extract, never raw.

Immune Support Supplements Compared

Ingredient	Authorised GB immune claim?	What UK guidance or research says
Vitamin D	Yes	NHS: consider 10µg a day from October to March
Vitamin C	Yes	Does not prevent colds for most people; may slightly shorten them
Zinc	Yes	Evidence on cold duration is low certainty; avoid long-term high doses
Vitamin A, B6, B12, folate	Yes	Most people get enough from a varied diet
Selenium, copper, iron	Yes	Iron only if advised; too much can be harmful
Elderberry	No	Evidence limited and mixed
Echinacea	No	Evidence inconsistent

How to Choose an Immune Supplement

• Start with vitamin D. Check the label gives at least 10µg (400 IU) per day.
• Check the %NRV. Look for vitamin C and zinc at meaningful but sensible levels, rather than very high doses.
• Read the claims. Authorised wording is "contributes to the normal function of the immune system". Anything louder is marketing.
• Avoid doubling up. If you already take a multivitamin, add up your totals before buying a separate immune product.
• Ask first if it applies to you. If you are pregnant, breastfeeding or on medication, speak to your GP or pharmacist.

Where GUUDIES Fits

We built the immune-relevant nutrients into the daily routine rather than selling a seasonal extra. The Daily Greens+ gummy, one of the six gummies in each GUUDIES daily pouch, provides vitamin D3 at 20µg, vitamin C at 80mg, vitamin A, B6, B12 and copper, and zinc at 2.75mg as bisglycinate. Vitamin D, vitamin C and zinc contribute to the normal function of the immune system. 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 vitamin D3 page and zinc and minerals page, or see what is in a GUUDIES pouch.

Common Questions

What is the best immune support supplement in the UK?
For most adults, a daily vitamin D supplement from October to March is the one backed by NHS advice. Beyond that, a balanced multivitamin covering vitamin C and zinc at sensible levels is enough for most people with a reasonable diet.

Which vitamins are good for the immune system?
Vitamins A, B6, B12, C and D, folate, and the minerals zinc, copper, iron and selenium all contribute to the normal function of the immune system.

Can supplements boost your immune system?
No supplement can legally claim to boost immunity in the UK. Nutrients such as vitamin D, vitamin C and zinc contribute to normal immune function, which matters most if you would otherwise fall short.

When should I start taking vitamin D?
The NHS suggests considering it from October through to March, when UK sunlight is too weak for your skin to make it.

Are elderberry gummies worth it?
Elderberry has no authorised immune claim and the research is limited. If a gummy contains vitamin C or zinc, those are the ingredients doing the authorised work.

Can I take immune supplements with medication?
Check with your GP or pharmacist first, particularly if you take regular medication or are pregnant or breastfeeding.

Sources

• NHS, Vitamin D: nhs.uk
• Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews, 2013: doi.org
• Nault D et al. Zinc for prevention and treatment of the common cold. Cochrane Database of Systematic Reviews, 2024: doi.org
• GB Nutrition and Health Claims Register: gov.uk

Related Reading

Vitamin D Deficiency Symptoms UK · How Much Vitamin D Should I Take? · Vitamin C Gummies · Does Vitamin D Help the Immune System? · See our full ingredient list