What are the symptoms of iron deficiency?

Common symptoms include persistent tiredness and fatigue (not relieved by rest), pale skin (especially inside the lower eyelids and nail beds), shortness of breath on exertion, dizziness or lightheadedness, cold hands and feet, headaches, brittle nails, hair thinning or loss, restless legs, unusual cravings for ice or dirt (pica), and difficulty concentrating. Many people with mild iron deficiency have no symptoms at all — it is often found on routine blood tests.

What blood tests check for iron deficiency?

The key tests are ferritin (your iron stores — the most sensitive single test), iron studies (serum iron, transferrin, transferrin saturation), and full blood count (haemoglobin, MCV). Ferritin below 30 micrograms per litre suggests iron deficiency. Ferritin below 15 confirms depletion. Your GP will interpret these together. Ask for iron studies if you have symptoms — a full blood count alone can miss early iron deficiency.

Who is at risk of iron deficiency?

Women with heavy periods (the most common cause in premenopausal women), pregnant women (iron needs double in pregnancy), vegetarians and vegans (plant-based iron is less well absorbed), frequent blood donors, people with coeliac disease or inflammatory bowel disease, growing children and teenagers, endurance athletes, and people taking proton pump inhibitors (PPIs) long-term which reduce iron absorption.

Iron Deficiency

Symptoms, causes, who's at risk, and when to see your GP.

📋 Source: NHMRC Nutrient Reference Values for Iron (2006; updated 2017). Therapeutic Guidelines: Iron deficiency. RANZCOG guidance on iron in pregnancy. Ferritin thresholds per Gastroenterological Society of Australia (GESA) guidelines.
Your doctor or healthcare provider knows your history and circumstances — always follow their personalised advice over general information.

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Symptoms of low iron

Iron deficiency develops gradually. You may not notice symptoms until your iron is significantly low. Common signs include:

Most common

😴 Persistent tiredness not relieved by rest

🫥 Pale skin, lips, and inner eyelids

😮‍💨 Breathlessness on exertion

💫 Dizziness or lightheadedness

🥶 Cold hands and feet

Less obvious

🤕 Frequent headaches

💅 Brittle, spoon-shaped nails

💇 Hair thinning or increased hair loss

🦵 Restless legs (worse at night)

🧊 Cravings for ice, dirt, or starch (pica)

Important: Many people with mild iron deficiency have no symptoms. It is commonly found on routine blood tests, particularly in women of reproductive age. If you have any of these symptoms, ask your GP for iron studies — don't assume it's "just tiredness."

Who is at risk?

🩸Women with heavy periods — the most common cause in premenopausal women. Losing more iron each month than you replace. 🤰Pregnant women — iron needs roughly double during pregnancy (from 18mg to 27mg/day). Demand increases significantly in the second and third trimesters. 🥬Vegetarians and vegans — plant-based (non-haem) iron is absorbed at 2-5% vs 15-35% for meat-based (haem) iron. Need almost double the recommended intake. 🩹Frequent blood donors — each donation removes ~250mg of iron. Donors should wait the recommended interval and consider supplementation. 🫄Coeliac disease or IBD — malabsorption reduces iron uptake from food, even with adequate dietary intake. 👶Growing children and teenagers — rapid growth increases iron demands. Adolescent girls are at particular risk once menstruation begins. 🏃Endurance athletes — "foot strike haemolysis" and increased iron losses through sweat and the gut. 💊Long-term PPI use — proton pump inhibitors (omeprazole, pantoprazole) reduce stomach acid needed for iron absorption.

Check your daily iron intake

Are you getting enough iron from your diet? Use our calculator to check your recommended intake based on your age, sex, and diet type.

Calculate my iron needs →

What blood tests to ask for

If you suspect low iron, ask your GP for iron studies — not just a full blood count. Here's what the tests mean:

Test	What it measures	Low iron looks like
Ferritin	Your iron stores (most sensitive test)	<30 μg/L = likely deficient. <15 = depleted.
Serum iron	Iron circulating in your blood right now	Low (but varies during the day)
Transferrin saturation	% of your iron transport protein carrying iron	<20% suggests deficiency
Haemoglobin (FBC)	Oxygen-carrying protein in red blood cells	<120 g/L women, <130 g/L men = anaemia
MCV (FBC)	Red blood cell size	Low (microcytic) — cells are smaller than normal

Key point: You can be iron deficient with a normal haemoglobin. Ferritin drops first (depleted stores), then haemoglobin drops later (anaemia). Don't wait until you're anaemic — ask for ferritin if you have symptoms or risk factors. Medicare sets rules on how often iron studies can be repeated — GPs can check these on the re-testing frequency guide.

Treatment

Diet first — increase iron-rich foods, especially haem iron (red meat, chicken, fish). Combine plant-based iron with vitamin C (e.g. spinach with lemon juice) to boost absorption. See our iron-rich foods guide →

Iron supplements — your GP may recommend iron tablets (e.g. ferrous fumarate, ferrous sulfate). Take on an empty stomach or with vitamin C. Common side effects: constipation, black stools, nausea. If you can't tolerate tablets, liquid formulations or alternate-day dosing may help.

Iron infusion — if tablets don't work, aren't tolerated, or you need rapid correction (e.g. before surgery, severe anaemia, third trimester pregnancy), your GP can arrange an intravenous iron infusion. Read our iron infusion guide →

Find the cause — treating iron deficiency without finding the cause is incomplete. Your GP will investigate why you're low: heavy periods? Diet? Coeliac disease? In men and postmenopausal women, iron deficiency should always prompt investigation for gastrointestinal blood loss (possible referral for colonoscopy/gastroscopy).

Iron needs increase to approximately 27mg/day during pregnancy (up from 18mg). Most pregnant women need supplementation — your GP or midwife will check ferritin at booking and again in the second trimester.

Iron deficiency in pregnancy increases the risk of preterm birth, low birth weight, and postnatal depression. If your ferritin is below 30 μg/L, supplementation is recommended. If below 20 μg/L in the third trimester or haemoglobin is low, an iron infusion may be offered for faster correction.

Children aged 1-3 are at particular risk — iron stores from birth are depleted by around 6 months, and toddlers are often fussy eaters. Too much cow's milk (more than 500mL/day) can reduce iron absorption and cause microscopic gut blood loss.

Signs in children: irritability, poor appetite, slow growth, frequent infections, pica (eating dirt or ice). If you suspect low iron in your child, ask your GP for a blood test.

Yes. Iron overload is harmful. Do not take iron supplements unless recommended by your GP based on blood test results. The upper limit for adults is 45mg of elemental iron per day from supplements.

People with haemochromatosis (iron overload disorder, common in Australians of northern European descent) should NOT take iron supplements. If you have a family history of haemochromatosis, ask your GP for an iron studies test.

Iron tablets are a leading cause of poisoning in children. Keep all supplements out of reach.