What’s The Difference Between Ferritin And Iron?

If you’ve recently had a blood test to check for iron deficiency or are thinking of taking an iron deficiency blood test, you may be a bit confused about the biomarker Ferritin. Why is this biomarker used and how is it different from iron?

So, what is the difference between ferritin and iron?

Ferritin is a blood protein and is the main storage protein for iron, alongside hemosiderin. Ferritin keeps hold of iron and releases it when the body needs it. Iron is a mineral found in red blood cells that carries oxygen around the body.

Ferritin is a good indicator of how much iron is stored within your body, with low levels indicating iron deficiency anaemia.

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Ferritin is the best indicator of iron deficiency

Approximately one-quarter of the total iron in the body is stored as ferritin. Ferritin has a vital function in the absorption, storage and release of iron. Most ferritin is found in the liver but it can also be present in the spleen, bone marrow and muscles.

Ferritin is therefore the best indicator of iron deficiency. By assessing the levels of ferritin in the body, you can clearly identify whether you might be iron deficient or even have levels that are raised. If a ferritin test comes back showing a risk of iron deficiency, further tests may be suggested by a medical professional, including a test for iron itself.

What are normal ferritin levels?

Ferritin reflects how much iron your body has in reserve. Too low, and you might experience fatigue, dizziness or shortness of breath. Too high, and it could point to inflammation or other health issues.

Ferritin Ranges for Adults (UK)

Women:

• <15 µg/L – Iron deficiency
• 15–29 µg/L – Low iron stores
• 30–99 µg/L – Indeterminate
• 100–310 µg/L – Normal
• >310 µg/L – High

Men:

• <15 µg/L – Iron deficiency
• 15–29 µg/L – Low iron stores
• 30–99 µg/L – Indeterminate
• 100–340 µg/L – Normal
• >340 µg/L – High

We looked at over 3,700 blood test results in 2025 and found the median ferritin level for men and women in the UK is 154 µg/L and 60 µg/L respectively.

What should your iron levels be?

Iron is measured by testing haemoglobin in your blood. In the UK, normal haemoglobin levels are between 130-170g/L for men and 120-160g/L for women. Haemoglobin levels below this could be an indicator of anaemia.

Symptoms of Low Ferritin

If you have low ferritin levels, you may experience symptoms including:

• Pale skin
• Fatigue
• Very low energy levels
• Headaches
• Difficulty breathing
• Dry skin and hair
• Restless leg syndrome
• Increased heartbeat

Iron deficiency usually occurs because of increased requirements or pressure on the body. For example:

• High-performance sport
• Vegetarian/vegan diet with limited iron supply
• Pregnancy
• Increased blood loss e.g. menstruation

Up to 20% of menstruating women are iron deficient and up to 5% have iron deficiency anaemia. In females, iron status is largely dependent on menstrual blood loss. In Europe, the amount of blood loss resulting from menstruation is on average 30 ml per day which is equivalent to a 0.45mg daily loss of iron.

Because iron deficiency is a nutritional deficiency and is one of the most prevalent in Europe, it is possible to prevent it.

Do low ferritin levels make you anaemic?

Because ferritin is a storage protein for iron, low ferritin levels are not the cause of anaemia, instead, low iron levels are the cause of iron deficiency or iron deficiency anaemia. However, because blood levels of ferritin are directly proportional to the body’s iron stores, ferritin is a good indicator of the condition.

Symptoms of High Ferritin

It is also possible for excess iron to occur, too. The ferritin test is used in combination with other tests to check for iron overload. High levels of ferritin are considered when blood levels are greater than 154 µg/L.

One condition which can result from the build-up of iron is haemochromatosis, which is an inherited condition and occurs over many years. The iron builds up slowly in the body and causes unpleasant symptoms such as:

• Muscle weakness
• Unexplained weight loss
• Abdominal pains
• The loss of body hair
• Pains in the joints
• Reduced libido
• Women may have irregular periods
• Men may find it difficult to get or keep an erection

If left untreated, the condition can damage the joints as well as organs such as the heart, liver and pancreas.

Improving Iron Nutrition

There are three factors to take into consideration when looking to improve your iron nutrition:

• The quantity of iron
• The quality of iron
• Composition of your diet

There are two types of iron; haem and non-haem. Haem iron is found in animal products like meat, fish and poultry. Non-haem iron is found in foods such as green leafy vegetables, cereals and legumes.

In a diet which includes meat, at least 40% of the total iron absorbed by the body comes from haem iron sources, due to it being absorbed better by the body than non-haem iron. Red meats contain more haem iron than white meats such as chicken and pork and this should be taken into consideration when trying to improve your iron status.

Individuals who only eat non-haem sources of iron should make sure they are getting an adequate intake. There are certain dietary components which can enhance iron absorption, too, such as vitamin C.

Because dietary iron can be poorly absorbed the body has a clever way of conserving its iron stores. When our red blood cells are broken down, the body reabsorbs the iron released from them to boost iron stores. The usual 1-2 milligram daily loss of iron is usually replenished by the absorption from dietary sources in the small intestine.

Summary

Ferritin is a blood protein which stores iron and is a good indicator of how much iron is present in the body. The amount of ferritin present in the blood reflects the total amount of iron available to the body for future use. Ferritin releases iron as it is required by the body for many functions including the production of new red blood cells. Symptoms of low ferritin levels include fatigue, weakness, dizziness, shortness of breath and headaches. Whereas, symptoms of high levels of ferritin include fatigue, abdominal pain, unexplained weight loss, joint pain and weakness.

If there are no underlying health conditions causing low ferritin levels, then improving your diet can help improve iron levels and absorption of iron by the body.