First things first: the reference intake for vitamin C is 80 mg per day. Even so, many products provide 1,000 mg. That is not an arithmetic error but a deliberate decision, and it has to do with a property of the vitamin, not with marketing.
Why the reference intake is not the whole answer
The reference intake describes the amount that covers the requirement of the general population. It is a lower boundary, not an optimum. Vitamin C is also water-soluble: the body does not build up any appreciable store, and whatever it does not currently need it excretes via the kidneys.
Both things follow from that. A higher amount is unproblematic, because any excess leaves the body again. And it is of limited use, because the proportion the body takes up falls as the single dose rises. So if you take a very high amount, you can spread it across the day instead of taking it all at once.
What vitamin C does in the body
Vitamin C contributes to the normal function of the immune system, to the reduction of tiredness and fatigue, to normal energy-yielding metabolism, to the normal function of the nervous system, to normal psychological function, to the protection of cells from oxidative stress and to normal collagen formation for the normal function of skin, bones, cartilage, gums, teeth and blood vessels. It also increases iron absorption.
The last point is often overlooked and is the most useful one in practice: vitamin C increases iron absorption. If you eat a vegetarian or vegan diet, that gives you a concrete reason to think of the two together and to have them at the same meal.
The point about collagen formation is the reason vitamin C belongs in every collagen product worth taking seriously.
Why is zinc so often listed alongside?
Because the two overlap on one point:
Zinc contributes to the normal function of the immune system, to the protection of cells from oxidative stress, to the maintenance of normal skin, hair and nails and to normal cognitive function.
So the combination brings together two nutrients that act at the same place in one tablet. In practice that saves a second tub.
Bioflavonoids, natural vitamin C and other label terms
Citrus bioflavonoids are plant compounds that occur naturally alongside vitamin C in the peel of citrus fruit. In a supplement they approximate the composition of the fruit. There is no authorised claim of their own for them, they are a feature of the formula, not a promise of an effect.
The term natural vitamin C is worth putting into context: chemically, ascorbic acid is identical whether it was obtained from a fruit source or by fermentation. The difference lies in the accompanying matrix, that is, in what else comes with it.
Our Vitamin C 1000 mg with zinc
Our Vitamin C 1000 mg with zinc provides 1,000 mg vitamin C and 10 mg zinc per tablet, plus citrus bioflavonoids. One tablet a day, 200 tablets per tub, which means it lasts around 200 days.
The 10 mg zinc corresponds exactly to the reference intake, so 100 %. That is a deliberate choice: unlike vitamin C, zinc is not water-soluble in the same sense, and here more is not automatically better.
In short
- The reference intake of 80 mg is a lower boundary, not a target value.
- Vitamin C is water-soluble. Excess amounts are excreted, and very high single doses can be spread across the day.
- The point most underrated in practice: vitamin C increases iron absorption, which is particularly relevant on a plant-based diet.
- Zinc is a sensible addition but should not be overdosed. 10 mg corresponds to the full reference intake.
