Vitamin C is probably the most famous supplement in the world and the first thing we reach for at the first sneeze. But does it really protect against colds, what else is it important for, and is there any point in swallowing grams of it? Let us take a calm, honest look at the benefits, the dosage and the safety.
Does this sound familiar?
- You reach for vitamin C at the first sign of a cold
- You wonder whether a big dose is better
- You want some support for your immunity and your skin
Why vitamin C matters
Vitamin C (ascorbic acid) is a water-soluble vitamin that the body cannot make on its own, so we need to get it from food. It is a powerful antioxidant and takes part in a whole range of processes, but its most important role is as a cofactor for building collagen. It also supports the normal function of the immune cells and the body's protective barriers (Carr and Maggini, Nutrients, 2017).
An interesting detail about dosing: the same review notes that plasma levels of vitamin C are already saturated at around 100 to 200 mg a day. In other words, above a certain amount the body simply gets rid of the excess.
Vitamin C and colds: the most common myth (honestly)
This is the topic surrounded by the most confusion, so we will be especially honest about it. A large Cochrane review, pooling 29 comparisons with more than 11,000 participants, found that regular vitamin C intake does not significantly reduce how often ordinary people catch colds (Hemila and Chalker, Cochrane, 2013).
So what does it do? It shortens the length of a cold a little, by about 8% in adults and 14% in children. And there is one important exception: in people under heavy physical stress, such as marathon runners, skiers and soldiers, the frequency drops by half. The honest conclusion: vitamin C is not a shield against colds for everyone, but it can slightly shorten the illness, and under extreme exertion the benefit is more noticeable.
Vitamin C, collagen and skin
This is where the benefit is least disputed. Vitamin C is an essential cofactor for collagen synthesis, and the skin holds high concentrations of it. One review describes how vitamin C supports collagen building and helps protect the skin from oxidative damage (Pullar and colleagues, Nutrients, 2017). The honest caveat from the same review: the benefit of topical vitamin C in cosmetics is less well proven than an adequate intake through food and supplements.
Vitamin C and iron absorption
A practical and well-supported benefit: vitamin C is among the most effective enhancers of iron absorption from plant sources (Teucher and colleagues, 2004). That is why pairing iron-rich plant foods with a source of vitamin C, for example a squeeze of lemon over vegetables or beans, improves iron intake. A handy trick, especially for vegetarians and vegans.
💡 Did you know...
- Unlike most animals, humans cannot make vitamin C on their own and rely on food.
- A severe deficiency causes scurvy, a disease that claimed the lives of many sailors in the past.
- Plasma levels are already saturated at around 100 to 200 mg a day, and the excess is flushed out.
- Peppers, citrus fruits, blackberries, parsley and broccoli are rich in vitamin C, not just oranges.
Vitamin C does not protect everyone from colds. But it is essential for collagen, and the body is already saturated at modest doses, so more does not mean better.
Caution: more is not better
Megadoses do not bring more benefit and are not harmless. A large prospective study of nearly 200,000 people found that supplemental vitamin C, especially above 1,000 mg a day, is linked to a higher risk of kidney stones in men, whereas vitamin C from food showed no such link (Ferraro and colleagues, 2016).
The rough upper limit for adults is around 2,000 mg a day, and very high doses can also cause stomach discomfort. So the aim is a sensible daily intake, not grams just in case.
Who are we to write about this
Cvetita Herbal has been working for over 10 years as a European manufacturer with over 1 million happy customers. That is exactly why we would rather tell you that vitamin C is not a miracle against colds, but is important for collagen and immunity, than sell you megadoses. The informed choice is the better choice.
Vitamin C
Our Vitamin C comes in a convenient capsule form with 600 mg per capsule, a sensible amount for everyday support. It makes sense if your diet is low in fresh fruit and vegetables, or if you are going through a period of greater need, to cover your daily intake without unnecessary megadoses.
💡 How to use it: Take according to the dosage on the packaging, preferably with food. For better iron absorption, combine it with iron-rich plant foods. Do not exceed the recommended dose.
What to realistically expect
For collagen and skin: an essential cofactor for collagen synthesis, the least disputed benefit.
For colds: it does not prevent them, but it can slightly shorten the illness, and under heavy exertion it helps more.
For the dose: the body is saturated at modest amounts, and megadoses bring no bonus.
What customers say
"I take it all year round as part of looking after my immunity and my skin. I like that it is a convenient capsule with a clear dose."
- Charlotte H.
"I am on a plant-based diet and pair it with iron-rich foods. I take a sensible dose without going overboard."
- Oliver M.
Frequently asked questions
Does vitamin C protect against colds?
For ordinary people, no, it does not significantly reduce how often you catch them. It shortens the length a little, and under heavy physical stress it also halves the frequency.
How much vitamin C a day?
Plasma levels are saturated at around 100 to 200 mg a day. The rough upper limit is around 2,000 mg, but megadoses bring no extra benefit.
Can too much vitamin C be harmful?
Very high supplemental doses are linked to a higher risk of kidney stones in men and can cause stomach discomfort. Vitamin C from food is safe.
What else is it good for?
It is essential for collagen synthesis, supports the immune cells and significantly improves iron absorption from plant foods.
If your diet is low in fresh fruit and vegetables, or you are going through a period of greater need, a sensible daily dose of vitamin C covers the need without unnecessary megadoses.
GET VITAMIN CSources
- Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev, 2013. pubmed.ncbi.nlm.nih.gov/23440782
- Pullar JM et al. The roles of vitamin C in skin health. Nutrients, 2017. pubmed.ncbi.nlm.nih.gov/28805671
- Carr AC, Maggini S. Vitamin C and immune function. Nutrients, 2017. pubmed.ncbi.nlm.nih.gov/29099763
- Teucher B et al. Enhancers of iron absorption: ascorbic acid and other organic acids. Int J Vitam Nutr Res, 2004. pubmed.ncbi.nlm.nih.gov/15743017
- Ferraro PM et al. Total, dietary, and supplemental vitamin C intake and risk of incident kidney stones. Am J Kidney Dis, 2016. pubmed.ncbi.nlm.nih.gov/26463139
Food supplement. It does not replace a varied diet and a healthy lifestyle. It is not a medicine and does not treat diseases. Do not exceed the recommended dose. If you are prone to kidney stones, are taking medication, or are pregnant or breastfeeding, consult a doctor before use. This information is for educational purposes and does not constitute medical advice.