Iron Deficiency Anaemia: Signs, Causes, Tests and Treatment

In short: Iron deficiency anaemia happens when low iron stores mean your body cannot make enough haemoglobin to carry oxygen. Common signs are tiredness, lack of energy, shortness of breath, a pounding or fluttering heartbeat and pale skin. It is diagnosed with a simple blood test (full blood count and ferritin), but finding the cause of the iron loss matters just as much as treating it.

This guide, written by a Ready Health prescribing pharmacist, explains the signs of iron deficiency, who is at risk, how it is tested and treated in the UK, and when you need further investigation. We see patients from Wigan, Standish, Chorley, Bolton and Horwich.

What is anaemia?

Anaemia means you have fewer red blood cells, or less haemoglobin, than normal. Haemoglobin is the protein that carries oxygen around your body. The most common type in the UK is iron deficiency anaemia. Other types include anaemia caused by low vitamin B12 or folate, chronic disease or inherited conditions.

You can also be iron deficient without being anaemic: your iron stores (ferritin) are low but haemoglobin is still in range. This can still cause symptoms in some people.

What are the signs of iron deficiency anaemia?

Common symptoms

• tiredness and lack of energy
• shortness of breath, particularly on exertion
• noticeable heartbeats (palpitations)
• pale skin

Less common symptoms

• headaches and feeling faint
• ringing in the ears (tinnitus)
• a sore or smooth tongue, mouth ulcers or cracks at the corners of the mouth
• hair loss and brittle or spoon-shaped nails
• restless legs
• cravings to eat non-food items such as ice or paper (pica)
• difficulty swallowing

Mild anaemia may cause no symptoms at all and is often found on a routine blood test.

What causes iron deficiency?

• Heavy periods – one of the most common causes in women of reproductive age
• Pregnancy – when the body's iron needs increase
• Bleeding from the gut – for example from stomach ulcers, regular use of anti-inflammatory painkillers (NSAIDs) or aspirin, haemorrhoids, inflammatory bowel disease or, less commonly, bowel or stomach cancer
• Not absorbing iron well – such as with coeliac disease or after some types of stomach surgery
• Low dietary intake – more likely with restricted diets, though diet alone is rarely the only cause in adults
• Frequent blood donation or intense endurance exercise

How is iron deficiency anaemia diagnosed?

A blood test is needed to confirm iron deficiency. Typical tests include:

A clinician interprets your results alongside your symptoms, medicines and history.

When does iron deficiency need further investigation?

In men of any age and in women who no longer have periods, iron deficiency anaemia without an obvious cause should be investigated, because it can be a sign of bleeding from the gut. In the UK, people aged 60 and over with unexplained iron deficiency anaemia are referred on an urgent suspected cancer pathway. Your GP may also arrange a stool test (FIT). Do not ignore iron deficiency simply because supplements make you feel better.

Seek urgent help if you have black or bloody stools, vomit blood, chest pain or severe breathlessness.

How is iron deficiency anaemia treated?

• Treating the cause – for example managing heavy periods, reviewing medicines or treating coeliac disease.
• Oral iron – usually one tablet a day; taking it on alternate days may be suggested if side effects such as constipation, nausea or dark stools are troublesome. Treatment usually continues for around three months after haemoglobin returns to normal to rebuild stores. Blood tests check your response.
• Diet – iron-rich foods include red meat, beans and pulses, dark green leafy vegetables, nuts and fortified cereals. Vitamin C helps absorption, while tea and coffee with meals can reduce it.
• Intravenous iron – used in hospital settings if tablets do not work or are not tolerated.

Do not take iron supplements long term without a confirmed deficiency, as too much iron can be harmful. Keep iron tablets out of reach of children. A pharmacist or prescriber can advise which option is suitable for you.

Frequently asked questions

How long does it take to feel better on iron tablets?

Many people notice more energy within a few weeks, with haemoglobin rising over the following weeks. Your clinician will usually recheck your blood within about two to four weeks.

Can I be iron deficient with normal haemoglobin?

Yes. Ferritin can be low before anaemia develops, which is why ferritin is usually checked alongside a full blood count.

Is tiredness always caused by anaemia?

No. Thyroid problems, vitamin deficiencies, diabetes, sleep problems, low mood and many other factors can cause fatigue, so a broader assessment may be needed.

Should I take iron supplements just in case?

It is better to test first. Supplements can mask a problem that needs investigating and are not suitable for everyone.

Key takeaways

• Iron deficiency anaemia commonly causes tiredness, breathlessness, palpitations and pale skin.
• A full blood count and ferritin test confirm the diagnosis.
• Always find the cause, especially in men and post-menopausal women.
• Oral iron, usually continued for about three months after levels normalise, is the standard first treatment.

Sources and further reading

• NHS – Iron deficiency anaemia
• NICE CKS – Anaemia: iron deficiency
• NICE NG12 – Suspected cancer: recognition and referral

Last reviewed: October 2026 by Shamir Patel, Independent Prescribing Pharmacist, Ready Health. This article is general information and does not replace advice from your own clinician.

Feeling tired all the time? Ready Health in Standish, Wigan offers private blood tests, including full blood count, ferritin, B12 and folate, with a clinician to explain your results and next steps. Convenient for patients from Wigan, Chorley, Bolton and Horwich. Book a private blood test.