Vitamin C is the supplement most people have taken at some point, and the one where the marketing has drifted furthest from the biology.
Walk into any UK pharmacy and the shelf is dominated by 1000mg. Some go to 1500mg. The reference intake is 80mg. That gap is the single most useful thing to understand before you buy anything, and it is where this guide starts.
I sell a vitamin C supplement, so weigh that as you read. What I can offer in return is the reasoning behind the doses — and you can check it against anyone you like.
Why 1000mg is not ten times better than 100mg
Vitamin C is water-soluble and absorbed by a transport system that becomes saturated. That is the key fact, and almost nothing on the shelf reflects it.
At modest intakes, you absorb most of what you take. As the dose climbs, the proportion absorbed falls — the transporters are working flat out and the rest passes through. Blood levels plateau: past a certain point, taking more stops raising the amount in circulation and simply raises the amount in your urine.
This is not a fringe view. It is the reason the reference intake sits at 80mg rather than 1000mg, and the reason high-dose vitamin C is associated with digestive upset — the unabsorbed portion has to go somewhere.
What that means when you shop: the number on the front of the pack is not a measure of quality. A moderate dose you absorb and tolerate is worth more than a large one you mostly excrete. We have set out the numbers here.
The formats compared
Whole-food and fruit-derived capsules
Best for: most people taking vitamin C daily.
This is where our own product sits, and here is the genuine case for it. The vitamin C comes from fruit — usually acerola cherry, one of the richest natural sources there is — rather than added ascorbic acid, so it is far less acidic. That matters because the commonest reason people stop taking vitamin C is that a large acidic tablet did not agree with them.
It also lands at a dose in the range your body can actually use, rather than one built for the front of the pack.
The trade-off: fewer milligrams per capsule and a higher price per milligram. Fruit can only be concentrated so far. For daily use that matters far less than whether you are still taking it in three months.
Ascorbic acid tablets
Best for: cost per milligram.
Ascorbic acid is vitamin C — the same molecule as in fruit. Cheap, stable, well studied. Anyone telling you it is inferior because it is “synthetic” is overstating a case, and we have written honestly about what the source does and does not change.
The trade-off: it is an acid, and high-dose tablets are where most reports of stomach discomfort in this category come from.
Buffered vitamin C (sodium or calcium ascorbate)
Best for: people who specifically want a high dose without the acidity.
Ascorbic acid bound to a mineral, which raises the pH. Sensible if acidity is your issue. Check the mineral load if you are watching sodium.
Liposomal vitamin C
Best for: people who have decided absorption is their bottleneck and will pay for it.
The premium end. Claims of dramatically superior absorption are not authorised claims in Great Britain and should be treated as marketing unless a seller can show you something specific.
Effervescent tablets and gummies
Best for: people who will not swallow a capsule.
Effervescents often carry a meaningful amount of sodium; gummies carry sugar or sweeteners and usually less vitamin C than the pack implies. Convenience is the proposition — and if it is the difference between taking it and not, that is a real benefit.
What to check before you buy
- What is the actual vitamin C content, and the %NRV? On a fruit-derived product, check whether the headline number is the vitamin C or the weight of fruit it came from. Those are very different figures.
- Can you do the arithmetic? A label saying “500mg acerola at 25% vitamin C” lets you verify 125mg. A label saying only “acerola extract” does not.
- Is there added ascorbic acid in a product sold as whole-food? Legal and common, but it should be on the ingredients list, and it changes what the premium is buying.
- Does the dose suit how you will take it? High-dose on an empty stomach is where discomfort usually starts.
- Does the seller stay within the claims rules? Vitamin C has more authorised claims than almost any nutrient. There is no excuse for reaching past them.
How to spot a seller worth trusting
This is the easiest category in which to sell honestly, because vitamin C is so well provided for. All of the following are authorised:
- Vitamin C contributes to the normal function of the immune system
- Vitamin C contributes to the reduction of tiredness and fatigue
- Vitamin C contributes to the protection of cells from oxidative stress
- Vitamin C contributes to normal collagen formation for the normal function of skin, bones, cartilage, gums, teeth and blood vessels
- Vitamin C increases iron absorption
That is a great deal a seller is permitted to say. So when a vitamin C product promises to prevent colds, shorten illness or “boost” immunity, that seller has gone past a generous set of permitted claims by choice. It is worth wondering what else they are relaxed about.
And to be clear: no supplement may claim to prevent, treat or cure a cold. That is a medicinal claim, and it is not available to anyone.
Our recommendation
Natural Vitamin C provides 125mg per capsule — 156% NRV — from 500mg of acerola cherry extract standardised to 25% vitamin C. Both figures are on the label, so the arithmetic is there to check. There is no added ascorbic acid in the pot; the vitamin C is the fruit's own.
Alongside it: blackberry 108mg, rosehip 108mg, parsley leaf 50mg and elderberry 42mg, each declared by weight.
60 capsules at £24.99. Vegan, Halal and Kosher certified, made in the UK.
It is a comfortable daily amount, gentle enough to take without food, from a source you can check — which is the combination that keeps people taking it. That, more than the number on the front, is what decides whether a vitamin C supplement was worth buying.
Always read the label. Food supplements are not a substitute for a varied and balanced diet and a healthy lifestyle.
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