Vitamin C overdose: the most important questions and answers

Vitamin C Überdosis: Die wichtigsten Fragen und Antworten

Vitamin C is supposedly the most well-known vitamin for supporting a good immune system. In addition, this vitamin has many other functions in the body, such as the formation of cartilage and bone tissue and the regulation of oxygen supply in cells. In addition to the intake of vitamin C through food, supplementation with it is not unpopular. However, it can happen that an overdose of the vitamin is administered.

In this article we will give you a detailed look at the most important functions of vitamin C and what effects an overdose can have. You will also receive valuable advice on how to counteract a vitamin C overdose and still provide your body with it.

the essentials in brief

  • Vitamin C is a water-soluble vitamin that is involved in metabolic processes and active cell protection in the human body.
  • The vitamin can be absorbed through food, especially fresh vegetables. Alternatively, there are also supplements that should cover daily needs.
  • An overdose of vitamin C can lead to different consequences. The kidneys and the gastrointestinal tract are mostly affected, as well as the iron content in the blood.

Definition: What is Vitamin C?

Vitamin C is also known as ascorbic acid. It is a water-soluble vitamin that should normally be ingested regularly with food. It supports the body's immune system and is responsible for a healthy metabolism and cell renewal. Consequently, it strengthens the body's defenses and is even considered to be a crucial contribution to cancer prevention. (1)

Vitamin C can be absorbed primarily through fresh vegetables and fruit, especially citrus fruits and other local fruits. Alternatively, it is also buried in some meat and sausage products to make them last longer. Vitamin C is also available as a preparation, in tablet, powder or capsule form, for supplementation.

Background: What you should know about the dosage of vitamin C

Before we tell you what to do if you overdose on vitamin C, it's important to cover some basic things about the vitamin.

In the following we answer the most important questions about vitamin C, its intake and effects.

What functions does vitamin C have in the body?

Vitamin C must be supplied to the body from the outside. However, it has a multitude of extremely important functions in the human organism. In the following table we show you where the vitamin is particularly important and how it works there.

Where? What?
digestion Uptake of iron from plant foods
metabolism Protection of cells from free radicals that occur when taking medication and nicotine, UV radiation and normal metabolic processes
skin and bones Important for wound healing, building bone and cartilage tissue and forming collagen
immune system Supporting a good immune system in the body and thereby strengthening the body's own defences


Can Getting Enough Vitamin C Actually Prevent Colds?

In winter in particular, one often hears that an increased intake of vitamin C reduces the risk of catching a cold. However, there is no long-term study that actually confirms this effect. Vitamin C can help reduce the symptoms of a cold, but it doesn't significantly reduce the risk of contracting the common cold.

The origin of this myth lies in the fact that vitamin C strengthens the immune system.

However, even a healthy person with a good immune system can catch a cold. Therefore, different high-dose supplements do not necessarily contribute to faster recovery. (2)

What is the recommended daily dose of vitamin C?

For adolescents aged 15 and over and adults, the recommended daily dose of vitamin C is around 90 and 110 milligrams a day, according to the German Society for Nutrition (DGE). However, this recommendation is not the same for everyone.

The need for vitamin C also depends on gender.

On average, men have a higher need for the vitamin than women and children. However, it is recommended, especially during pregnancy, to consume more vitamin C. Smokers also have a higher need for vitamin C due to the higher metabolic losses.

How can I take vitamin C?

Vitamin C can be absorbed into the body both through food and through supplementation in the form of tablets or powder. Both variants are equally well absorbed by the body and differ only very slightly. (7)


While most people think of citrus fruits when it comes to high levels of vitamin C, other foods actually contain more of it. Many types of fruit and vegetables from Europe, such as rosehip, sea buckthorn or even broccoli, also contain plenty of vitamin C.


In addition to citrus fruits, many local fruits are also excellent sources of vitamin C. (Image source: 123rf/ Neumiler)

In the following table we give you an overview of which foods you can best absorb vitamin C with.

Groceries Vitamin C per 100g
nettle 330mg
Parsley 159mg
Red pepper 140mg
acerola 1700mg
rosehips 1250mg
strawberry 55mg

The popular apples also have a good vitamin C content, but differ significantly depending on the variety. While Braeburn leads the way with around 30mg/100g, the Golden Delicious can only boast around 10mg/100g.


Supplementation with vitamin C preparations is often very popular, especially in the winter months. The vitamin can be taken in through a variety of supplements, and taking tablets with a high dose of vitamin C is particularly widespread. Powders and capsules are also among the most well-known vitamin C supplements.

Normally, vitamin C supplementation is not necessary. Such preparations are often very expensive, regardless of the form in which they are purchased.

In addition, supplementation and the resulting overdose have consequences that will be explained in detail in a later answer.

What happens with a vitamin C deficiency?

Vitamin C deficiency does not usually occur in people who eat a healthy and balanced diet. However, there are some risk groups that have an increased need for the vitamin. These include smokers, pregnant and breastfeeding women, as well as diabetics and the elderly.

The symptoms of a deficiency are varied. Scurvy is a typical disease caused by it, which manifests itself in tiredness, weakness, muscle pain and a weakened immune system. In the case of an extreme deficiency, bleeding, gingivitis, joint pain, poor wound healing and water retention in the joints also occur. (6)

When is vitamin C dosed too high?

If the vitamin is supplied solely through food, an overdose is almost impossible. An overdose of the vitamin is more likely to occur when taking vitamin C preparations, despite a balanced diet. A person can consume up to 2000mg of vitamin C in a day. If this reference value is exceeded, the vitamin is excreted in the urine after a few hours.

A high-dose intake, i.e. more than 1000mg per day, is only recommended for a short period of time. You should only use this dosage if you have no previous exposure or want to minimize the symptoms of a cold.

Serious consequences and illnesses often occur with particularly high overdoses of more than 2000 mg of vitamin C per day over a longer period of time.

What are the symptoms of a vitamin C overdose?

In principle, the body cannot be poisoned by taking too much vitamin C. The consequences of a vitamin C excess are nevertheless numerous and they have a particular effect on digestion and kidneys, as well as on the iron content in the blood. (3.4)

digestive problems

Digestive problems are the most common result of vitamin C overdose. It usually causes either diarrhea or nausea. In particularly sensitive people, stomach cramps can also be triggered by an excess of vitamin C.

kidney problems

Water-soluble vitamin C is excreted via the kidneys. For people with pre-existing conditions and stress, an overdose can therefore pose a risk. The oxalic acid contained in the vitamin reacts with the calcium present in the body and settles in the kidneys. This significantly increases the risk of kidney stone formation.

excess iron

Vitamin C is known to increase the absorption of iron in the body. Therefore, an overdose can also lead to too much iron being absorbed. This particularly affects people who have the prerequisites for an excessive intake of iron anyway.

Excess iron over a long period of time puts a significant strain on the liver, heart, pancreas and central nervous system. (1.5)

For whom is an overdose of vitamin C particularly harmful?

For healthy people, an overdose of vitamin C is usually not harmful, as the vitamin is simply excreted from the body. Only people who take the vitamin from dietary supplements and are particularly sensitive to the vitamin can suffer from an overdose.

Likewise, pre-existing conditions, such as an increased risk of kidney stones or problems with the iron content in the blood, can have negative effects on a high dose of vitamin C.

However, these are usually different from person to person and can usually be determined with a blood test.

Vitamin C Overdose: Effective Approaches to Treatment and Prevention

In order to avoid an overdose of vitamin C in the best possible way, a few simple measures that should be followed are sufficient. These are explained in detail in the following paragraphs.

Stop supplementing

Supplementation with vitamin C preparations is usually only necessary in the event of a deficiency and should not be carried out in the long term.


Supplementation with vitamin C preparations is not necessary with a balanced diet. (Image source: unsplash/ Mika Baumeister)

In the event that an overdose of the vitamin occurs from the supplements, it is best to stop taking the supplements for some time and only provide the body with the vitamin C from the diet.

Balanced nutrition

If you pay attention to a balanced diet and a sufficient intake of fresh fruit and vegetables, you should be able to counteract an overdose or a deficiency of vitamin C. An excess of the vitamin caused purely by nutrition is almost impossible.

If you also do not belong to a risk group such as smokers, pregnant women or breastfeeding women, the intake of the vitamin through food is completely sufficient anyway.

Listen to your own body

A fundamental rule is also that you pay close attention to your body and any signs of deficiency or overdose. Especially when you supplement vitamin C, it is all the more important to pay attention to how your body reacts to the supplements, especially over a longer period of time.

So as soon as you notice any side effects, you should reconsider your vitamin intake. If you are not sure whether you are actually overdosing on vitamins, you can play it safe and consult a doctor.


Vitamin C is an essential vitamin for human health. As a rule, the daily requirement can be sufficiently covered by a balanced diet. It is contained in citrus fruits as well as local fruits and vegetables.

The likelihood of having an excess of vitamin C in the body is increased by long-term use of high-dose supplements. Excess vitamin C is not dangerous for healthy people, but it can cause long-term consequences, such as digestive problems and kidney damage.

The easiest way to avoid an overdose is to eat a balanced diet, avoid vitamin C supplements and just pay close attention to your own body.

Individual proofs(7)

  1. Study on the effect of vitamin C in the prevention and cure of diseases such as diabetes, cancer and arteriosclerosis. Source
  2. Study on the influence of vitamin C intake on the prevention and control of the common cold Source
  3. Article linking several studies into the long-term effects of vitamin C supplementation . Source
  4. Report on the Safety and Effects of High Dose Intake of Vitamin C. Source
  5. Study on the influence of vitamin C as a risk factor for people with high blood iron levels. Source
  6. Book that provides general information on taking vitamin C and places a special focus on deficiency symptoms and their consequences. Source
  7. Study on the availability of natural vitamin C and the absorption capacity of synthetic and natural vitamin C in the human body. Source
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