Excess iron: This is why too much iron in the blood is dangerous

A young woman holds her stomach with her hands.  The body can react to excess iron with abdominal cramps.

Abdominal cramps and exhaustion: These are often the first symptoms of an excess of iron.
Iron deficiency is widespread. However, it is not advisable to take iron supplements as a precaution: Why too much iron can be dangerous.

Iron is an important mineral. It is part of the red blood cells and enables them to transport oxygen to all parts of the body. Iron is also an important component of muscle cells and necessary for the production of numerous enzymes in the body.

Despite the important functions of iron, many people around the world suffer from iron deficiency – especially women. Iron-rich foods and iron supplements are therefore part of a healthy diet for many people. However, few people know that too much iron can be harmful to your health .

You can find out here what you need to pay attention to when supplementing with iron and how an excess of iron becomes noticeable.

Iron in the blood: These values ​​are normal

Most of the iron in the human body is contained in hemoglobin. Therefore, your iron supply is examined using a blood test. Various values ​​are measured and their interaction is assessed – including:

  • Serum iron : normal range men 60 to 160 / women 40 to 150 micrograms per deciliter
  • Ferritin : Normal range for men 30 to 300 / women 10 to 150 micrograms per liter
  • Transferrin : Normal range men 1.7 to 3.3 / women 1.6 to 3.5 grams per liter

Transferrin is a protein that transports iron in the blood. It transports the iron absorbed in the intestine or released during breakdown processes throughout the body. Ferritin is an iron storage protein – the ferritin in the blood reflects the body’s iron balance.

In order to check your iron balance, these laboratory values ​​should always be measured and assessed together in the blood. Only the interaction makes an accurate diagnosis possible. If the measured blood values ​​are above the stated normal range, there is by definition an excess of iron – if they are below this, there is an iron deficiency. However, age, gender and internal laboratory differences can influence the measured values. An assessment of your iron levels should therefore only be carried out by experts.

Increased iron levels: These are the causes

Iron is very important for the human organism. Therefore, the body tries to retain as much of the mineral in the body as possible and recycles much of the iron it absorbs. However, only a very small proportion is excreted – around one to two milligrams per day.

Normally this is not a problem because the body only absorbs as much iron as it needs. However, in some cases this process is disrupted. The iron value is then too high and this is referred to as iron excess, also known as iron overload. The most common causes for this are:

  • Iron storage disease (hemochromatosis)
  • Overdose of iron supplements
  • Repeated blood transfusions
  • Severe liver damage, for example due to alcohol addiction

Increased iron levels due to iron storage disease

A possible cause of high iron levels is the hereditary iron storage disease, also called hemochromatosis . It is the most common inborn error of metabolism in Europe. Around one in 1,000 people are affected – without knowing it. The reason: The symptoms of the disease usually only become apparent at an advanced age.

In hemochromatosis, due to a genetic defect, the body absorbs more iron from food than it needs and can dispose of. As a result, the iron content in the blood increases and iron is deposited in organs and tissues, such as the heart, liver or skin. You can find more information about hemochromatosis here .

Excess iron: overdose of iron supplements

Every person needs to get iron through their diet. The good news is that many foods contain small amounts of iron. Since many people still suffer from an iron deficiency , some take iron supplements as a precaution – not least because they are available in abundance in drugstores and pharmacies.

However, this can be dangerous, especially if you unknowingly suffer from impaired liver function or hemochromatosis. This can quickly lead to an overdose of iron. The Federal Institute for Risk Assessment (BfR) therefore recommends that dietary supplements with iron only be taken after consultation with a doctor.

Too much iron: these are the consequences

An overdose of iron can occur even without a previous illness – for example if you use high-dose preparations from the internet or accidentally take too much. Taken once or over a short period of time, too much iron can temporarily cause vomiting, diarrhea, and black stools .

However, if you have taken too much iron over a long period of time, it can be dangerous in the long term. Regardless of whether it is due to a long-term overdose, iron storage disease or alcohol addiction – the excess iron is deposited in the cells of various organs and tissues and damages them. Those affected are:

  • Heart and cardiac muscles
  • liver
  • Joints
  • skin
  • pancreas
  • pituitary gland
  • thyroid
  • Gonads (testes and ovaries)

The consequences are tissue damage and poisoning, which can manifest themselves in very different symptoms depending on the organs affected.

Symptoms of a long-term excess of iron are varied

Tactile examination of the thyroid
Problems with the thyroid: This organ, along with the liver, is severely affected by an excess of iron. 

The problem with an excess of iron: The symptoms only appear gradually and are often non-specific. The first signs include exhaustion and weakness. Iron overload is therefore often only noticed when the accumulation of the mineral in the tissues is already very high.

The most common consequence is liver disease. But the following problems can also occur:

  • stomach pain
  • Bronze skin (bronze diabetes)
  • Joint pain, especially in the hands
  • Underactive thyroid ( hypothyroidism )
  • Prediabetes or diabetes
  • Increased risk of liver or pancreatic cancer
  • infertility
  • Heart failure or heart failure (uncommon)

The signs can also differ in men and women. Specific symptoms in men often affect the liver and pancreas. Warning signs are often yellowish skin (jaundice), pale, foul-smelling stools (fatty stools) or signs of diabetes (such as increased thirst and frequent urination). In addition, iron deposits in the testicles can lead to erectile dysfunction .

Women, on the other hand, suffer more from vague symptoms that affect the whole body, such as fatigue and joint pain .

What to do if the iron level is too high?

If you experience these symptoms and you suspect iron excess, you should be examined by your family doctor. A close laboratory check is then usually carried out, during which your iron levels (serum iron, ferritin, transferritin) are checked. To rule out hereditary iron storage disease, genetic tests and sometimes a liver biopsy are also carried out.

If congenital hemochromatosis is present, regular blood sampling (phlebotomy) is generally the best treatment. It protects against further organ damage – but cannot reverse existing damage. These must then be treated separately.

If iron overload is due to an overdose of nutritional supplements or repeated blood transfusions, treatment usually consists of so-called iron chelation therapy. The medications used bind excess iron and thus reduce iron levels. In this way, the therapy prevents or delays organ damage.


Iron is an important mineral and essential for your health. However, too much iron in the blood damages various organs and can therefore be dangerous. A hereditary iron metabolism disorder and overdosing with nutritional supplements are the most common causes of an excess of iron. To counteract the risk of excess iron, you should only take iron supplements after prior medical consultation.


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