# Immune Support

Nine ingredients make up this comparison: vitamin C, vitamin D3, zinc, a multivitamin, probiotics, omega-3, selenium, quercetin and echinacea. Eight of them are ranked on price per capsule or tablet; echinacea keeps the price of the whole box, and neither ranking knows what dose is inside.

So the dose is the first job, taken off the back of the pack before two tubs are set side by side. A pack sold by two shops produces two rows with two prices, because nothing links a row in one shop to a row in another. What to take is a conversation with a GP or pharmacist.

Best and median price per ingredient, updated 18 October 2026

| Ingredient | Best price | Product | Median price | Shops | Products |
| --- | --- | --- | --- | --- | --- |
| [Vitamin C](https://supplementscanner.co.uk/category/vitamin-c) | £0.01 /capsule | [Potassium Citrate 1300mg with Vitamin C](https://supplementscanner.co.uk/p/simply-supplements-potassium-citrate-1300mg-with-vitamin-c-132122) (Simply Supplements) | – | 10 | 61 |
| [Vitamin D3](https://supplementscanner.co.uk/category/vitamin-d3) | £0.02 /capsule | [Vegan Vitamin D3 400iu Tablets](https://supplementscanner.co.uk/p/simply-supplements-vegan-vitamin-d3-400iu-tablets-133415) (Simply Supplements) | – | 9 | 93 |
| [Zinc](https://supplementscanner.co.uk/category/zinc) | £0.04 /capsule | [Zinc Tablets 15mg – 180 tablets / [Multibuy 1]](https://supplementscanner.co.uk/p/simply-supplements-zinc-tablets-15mg-180-tablets-multibuy-1-133329) (Simply Supplements) | – | 9 | 54 |
| [Multivitamin](https://supplementscanner.co.uk/category/multivitamin) | £0.02 /capsule | [Multivitamins A,B,C,D & E 100% NRV – 180 tablets / [Multibuy 1]](https://supplementscanner.co.uk/p/simply-supplements-multivitamins-abcd-e-100-nrv-180-tablets-multibuy-1-132945) (Simply Supplements) | – | 12 | 198 |
| [Probiotics](https://supplementscanner.co.uk/category/probiotics) | £0.12 /capsule | [Myprotein Daily Probiotic Capsules](https://supplementscanner.co.uk/p/myvitamins-myprotein-daily-probiotic-capsules-125707) (Myvitamins) | – | 10 | 139 |
| [Omega-3 / Fish oil](https://supplementscanner.co.uk/category/omega-3) | £0.03 /capsule | [Omega 3 Capsules 500mg](https://supplementscanner.co.uk/p/simply-supplements-omega-3-capsules-500mg-132093) (Simply Supplements) | – | 10 | 106 |
| [Selenium](https://supplementscanner.co.uk/category/selenium) | £0.27 /capsule | [Ultra Selenium](https://supplementscanner.co.uk/p/ultra-ultra-selenium-124803) (Vitabiotics) | – | 2 | 2 |
| [Quercetin](https://supplementscanner.co.uk/category/quercetin) | – | – | – | 0 | 0 |
| [Echinacea](https://supplementscanner.co.uk/search?q=echinacea) | £2.62 total price | [Dr Stuart's Echinacea Plus - 15 Bags](https://supplementscanner.co.uk/p/dr-stuarts-dr-stuarts-echinacea-plus-15-bags-130246) (Vitamin Planet) | – | 1 | 3 |

## The upper figures the NHS sets, and the figures on the front of a pack

The NHS puts an upper figure beside three of these: do not take more than 100 micrograms (4,000 IU) of vitamin D a day, do not take more than 25mg of zinc supplements a day unless advised to by a doctor, and 350μg or less a day of selenium is unlikely to cause any harm.

A British pack prints its own figures: 1,000mg is the usual vitamin C tablet, 15mg or 25mg the usual zinc one, and 55μg, 100μg or 200μg the usual selenium. Where a pack figure and an NHS figure happen to match, they are still answering different questions, and a price per capsule answers neither. That is why the label figure is read first.

## Micrograms on one box, international units on the next

[Vitamin D3](https://supplementscanner.co.uk/category/vitamin-d3) is the one ingredient here sold in two units at once: 10 micrograms is 400 IU and 25 micrograms is 1,000 IU, and both spellings sit in the same category. Cholecalciferol is D3 and ergocalciferol is D2; a vegan pack takes its D3 from lichen rather than from wool grease. Drops are sold in millilitres and only earn a per-unit price when the pack states a number of drops or servings. The same capsules turn up on [joints and bones](https://supplementscanner.co.uk/goal/joints-bones) and [menopause](https://supplementscanner.co.uk/goal/menopause).

## Zinc: what the compound weighs and what the mineral weighs

[Zinc](https://supplementscanner.co.uk/category/zinc) prints its compound on the front and its elemental content a line below, in milligrams, and only that second figure makes two tablets comparable. Gluconate, citrate, picolinate, bisglycinate and oxide carry different elemental weights at the same tablet weight, and lozenges are a format of their own. The same arithmetic is worked through for another mineral in buying magnesium.

[Selenium](https://supplementscanner.co.uk/category/selenium) is dosed in micrograms per tablet, as selenomethionine, sodium selenite or selenium-enriched yeast, and the form decides what the microgram figure is attached to.

## Vitamin C, quercetin and the %NRV column

[Vitamin C](https://supplementscanner.co.uk/category/vitamin-c) is where the front of a pack hides the most. Ascorbic acid, buffered vitamin C as calcium ascorbate, Ester-C as a trade name for that buffered form and time-release tablets can all print the same 1,000mg. Effervescent tablets and powders state a dose per tablet or per scoop, and without a count on the pack only the tub price is left.

[Quercetin](https://supplementscanner.co.uk/category/quercetin) is in milligrams per capsule, often as quercetin dihydrate, and is frequently sold with vitamin C, zinc or bromelain beside it; where the label adds those into a single total, only the quercetin line compares. A [multivitamin](https://supplementscanner.co.uk/category/multivitamin) gathers the vitamins and minerals from this list into one tablet at a lower dose than any single tub, and one tablet a day or two changes the daily cost while the ranking stays per tablet.

## Echinacea by the box, probiotics by the capsule

Echinacea has no category of its own and is found by name, so the pack keeps its whole price. That is the fairer measure here, because the word covers four objects that no single unit converts between. A tincture is sold by the millilitre and states an alcohol percentage. A capsule states milligrams of dried herb. An extract states a ratio, 4:1 for instance. A tea states neither. Purpurea, angustifolia and pallida are three plants besides, and root is not the aerial part. Divide the box price by the number of doses the pack states.

[Probiotics](https://supplementscanner.co.uk/category/probiotics) are compared per capsule on two label facts: the strains written out in full (Lactobacillus, Lacticaseibacillus, Bifidobacterium) and the CFU per capsule, counted at manufacture or at end of shelf life depending on the brand. The same capsules appear on [digestion and fibre](https://supplementscanner.co.uk/goal/digestion). For [omega-3](https://supplementscanner.co.uk/category/omega-3) the 1,000mg of fish oil on the front is not the measure: EPA and DHA two lines down are, and algae oil leads on DHA. Buying fish oil works through that line.

Boots and Holland & Barrett turn up in the related searches as places rather than products, and neither is scanned here. What the remaining words on a pack settle is set out in reading a supplement label.

## Sources

- [NHS: Vitamin D](https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/)
- [NHS: Vitamins and minerals, others](https://www.nhs.uk/conditions/vitamins-and-minerals/others/)

## Frequently asked questions

### What is the best immune supplement to take?

This comparison does not name a winner. It follows nine ingredients: vitamin C, vitamin D3, zinc, a multivitamin, probiotics, omega-3, selenium, quercetin and echinacea, with the label figure beside each one so that two packs can be matched before the price is read. Which of them suits you is a question for a GP or pharmacist.

### Which supplements do NHS recommend?

On vitamin D the NHS writes that everyone, including pregnant and breastfeeding women, should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter. For the other ingredients in this comparison its pages set out daily amounts and upper limits rather than an instruction to supplement.

### Do any immune supplements actually work?

That is a question about evidence, not about price, and Supplementscanner does not answer it. What a specific pack contains is on the back, in the ingredients list, and that list is what this comparison reads: the compound, the dose per capsule and the number of capsules in the tub.

### Is a multivitamin cheaper than buying the vitamins separately?

Per tablet it usually is, per ingredient it usually is not, because a multivitamin fits several names into one tablet at a lower dose than a single tub carries. The back of the pack gives a %NRV column rather than a plain figure, so read the milligrams and micrograms per ingredient first. Then add up the per-tablet prices of the separate tubs that carry those same figures.

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Source: Supplementscanner, https://supplementscanner.co.uk/goal/immunity (live prices per product)

Information for comparison, not medical advice. Ingredients are chosen based on what people often search for, not as a treatment.