Vitamin C: Effects, Daily Requirement and the Best Sources

Updated: October 2026

Vitamin C is the best-known vitamin of all. What it does, how much you need and where the most is found is partly surprising: citrus fruits don't top the list.

What does vitamin C do in the body?

Vitamin C is involved in many processes: it supports the formation of collagen for skin, cartilage and blood vessels, protects cells from oxidative stress and improves the absorption of iron from plant-based foods. It also contributes to the normal function of the immune system.

Important for putting it in context: in healthy people, extra vitamin C does not prevent a cold. According to analyses, taken regularly it shortens the duration of an infection slightly at best. You'll find more everyday tips in the article Strengthening Your Immune System: 5 Simple Tips.

The body can't produce vitamin C itself and can barely store it. That's why you should take it in daily through food. Chemically, the ascorbic acid in a tablet is identical to that in fruit. The advantage of whole foods lies in the accompanying compounds such as fibre and secondary plant compounds.

What is the daily requirement of vitamin C?

For adults, the DGE gives a reference value of 110 mg per day for men and 95 mg for women. Pregnant women need a little more, breastfeeding women considerably more. Because smoking lowers vitamin C levels, the recommendation for smokers is about 155 mg (men) and 135 mg (women).

You can reach these amounts almost on your own with one bell pepper or two kiwis.

An example for one day: a glass of orange juice (approx. 40 mg), half a red bell pepper at lunch (approx. 70 mg) and a kiwi in the afternoon (approx. 70 mg) already add up to around 180 mg, which is above the reference value. You can read more about nutrient supply in the article Which Vitamins for Autumn?

Which foods contain the most vitamin C?

Contrary to popular belief, citrus fruits are not the leaders. Sea buckthorn, bell peppers, parsley and blackcurrants have far more. The values are rounded reference figures per 100 g raw.

In the article Are Oranges Healthy? you'll find more about the orange.

A tip: combine iron-rich plant foods such as lentils, oats or spinach with vitamin C sources, such as a glass of juice or raw bell pepper. This improves iron absorption. If you like to drink yours, you can reach for cold-pressed juices, but keep in mind that vitamin C is also lost during pressing and storage. Cold-pressed and drunk quickly, the most is retained.

How does vitamin C survive cooking and storage?

Vitamin C is sensitive to heat, light, air and water. When cooking, some of it passes into the cooking water or is destroyed. Long storage and cut surfaces also reduce the content.

• Eat some of your vegetables raw, such as bell pepper, kohlrabi or crudités.
• Steam instead of boiling and use little water.
• Cut fruit and vegetables only shortly before eating.
• Store vegetables cool and dark and use fresh produce promptly.
• Frozen vegetables are often a good alternative, as they are flash-frozen shortly after harvest.

There is a little leeway: cooked vegetables still provide vitamin C, just less. What matters is variety over the day, not the perfect preparation of every single meal.

Do smokers or athletes need more vitamin C?

Smokers have a higher requirement because the body uses more vitamin C to neutralise free radicals. Levels also fall faster with stress, alcohol consumption and infections. Intense exercise raises the requirement only slightly, and the normal value is enough for most recreational athletes.

If you're at risk of deficiency, for example with a one-sided diet, medical advice makes sense. A pronounced deficiency is rare in Germany and shows up as scurvy with bleeding gums and poor wound healing.

In practice that means: if you smoke, you should eat at least two portions of fruit and three portions of vegetables a day and go for vitamin-rich varieties. The best protection remains quitting smoking, though, as vitamin C doesn't offset the strain. People who hardly eat any fresh fruit and vegetables, for example with a one-sided diet or in older age, should also keep an eye on their supply.

Can you take too much vitamin C?

Through food, an overdose is practically impossible. With high-dose supplements from about 1,000 mg per day, diarrhoea, nausea and stomach cramps occur more often. Over the long term, an increased risk of kidney stones is discussed in sensitive people, especially with a known tendency. If you have iron storage disorders, avoid high doses.

The body excretes excess vitamin C through the kidneys, so stocking up on high doses isn't worthwhile.

If you have a history of kidney stones, kidney disease or take certain medications, please ask at the pharmacy or your doctor before taking high-dose supplements. A daily amount of up to about 200 mg is easily reached with food, and the body absorbs it best.

Matching picks from frank.

If you'd like to try several kinds of fruit and vegetables, the easiest way to start is the Sample Set: a selection of our cold-pressed juices to get to know them. Freshly pressed juices don't replace fruit and vegetables, but they are an uncomplicated addition.

You might also like

• Are Oranges Healthy? 5 Facts About Vitamin C, Potassium and Orange Juice
• Strengthen Your Immune System & Stay Healthy: 5 Simple Tips
• Natural Vitamins or Synthetic Vitamins?

Frequently asked questions about vitamin C

How much vitamin C should I take daily?

The DGE recommends 95 mg (women) to 110 mg (men) per day for adults. This is easy to reach with fruit and vegetables.

Does vitamin C help against colds?

Taken regularly, it can shorten the duration of an infection slightly, but it doesn't prevent one. A balanced diet is the better foundation.

Is vitamin C from food better than from tablets?

The body uses both about equally well. Food also provides fibre and plant compounds, which is why it's usually the better choice.

Which fruit has more vitamin C than oranges?

Sea buckthorn, blackcurrants, kiwi and strawberries contain the same amount or considerably more, depending on the variety. Bell peppers are also a very good source.

Should you take vitamin C in the morning or evening?

A specific time of day is not proven. With supplements, taking them with a meal is easier on the stomach.

Note: This article is for general information and is not a substitute for medical or therapeutic advice. If you have complaints, pre-existing conditions, are pregnant or take medication, please talk to your doctor first.