Iron is the mineral your body uses to make haemoglobin, the protein in red blood cells that carries oxygen from your lungs to every tissue. It also contributes to normal energy-yielding metabolism, normal cognitive function, the normal function of the immune system and the reduction of tiredness and fatigue. Women of menstruating age need about 16 mg a day, men about 11 mg, because regular blood loss raises the requirement. Men rarely lack iron, and too much can be harmful, so a blood test should come before any supplement.
Key facts about iron
- Daily need (D-A-CH reference values, 2023): 16 mg for women before menopause, 14 mg after menopause, 11 mg for men; 27 mg in pregnancy and 16 mg after birth.
- The nutrient reference value (NRV) used on EU and Swiss labels is 14 mg.
- Iron from plants (non-haem iron) is absorbed less well than iron from meat and fish; vitamin C taken in the same meal increases iron absorption.
- Good plant sources per 100 g: pumpkin seeds about 8.8 mg, cooked white beans about 3.7 mg, cooked spinach about 3.6 mg, cooked lentils about 3.3 mg.
- Your iron stores are measured with ferritin in a blood test; the World Health Organization uses a ferritin value below 15 µg/L to define iron deficiency in healthy adults.
- The European Food Safety Authority (EFSA, 2024) considers up to 40 mg a day from all sources safe for adults; higher doses belong under medical supervision.
What does iron do in the body?
About two thirds of the iron in your body sits in haemoglobin. The rest is in myoglobin, which holds oxygen in muscle, in enzymes that produce energy in every cell, and in stores in the liver, spleen and bone marrow (ferritin). In the EU and Switzerland, the following health claims for iron are authorised. Iron contributes to:
- normal formation of red blood cells and haemoglobin;
- normal oxygen transport in the body;
- normal energy-yielding metabolism;
- the reduction of tiredness and fatigue;
- normal cognitive function;
- normal function of the immune system;
- the process of cell division.
When iron runs low, the body first empties its stores. Only later does haemoglobin fall, which is iron deficiency anaemia. That is why you can feel tired with a normal blood count but low ferritin. If tiredness is your main concern, our guide to which deficiencies make you tired compares iron with vitamin B12, vitamin D and others.
Iron benefits for women: why women need more
Women lose iron with every period, which is why the reference value before menopause is almost 50 % higher than for men. Iron deficiency is the most common nutrient deficiency worldwide, and women of reproductive age are among the groups most affected. Risk is higher if you:
- have heavy or long periods;
- are pregnant, have recently given birth or are breastfeeding;
- eat a vegetarian or vegan diet without planning iron sources;
- donate blood regularly or do a lot of endurance sport;
- have coeliac disease, inflammatory bowel disease or take acid-reducing medicines for a long time.
In pregnancy, the need rises to 27 mg a day because blood volume expands and the baby builds its own stores. After menopause the requirement drops to 14 mg. Women planning a pregnancy also need folate; read why women need folic acid for the details.
Iron benefits for men, and why more is not better
Men need 11 mg a day and, without monthly blood loss, usually get enough from a normal diet. Iron does the same work in men as in women: oxygen transport, energy-yielding metabolism, cognitive and immune function. Low iron in a man is unusual enough that doctors look for a cause, such as hidden bleeding in the gut, a malabsorption problem or frequent blood donation.
The bigger risk for many men is too much iron. The body has no active way to excrete excess iron. Hereditary haemochromatosis, one of the most common genetic conditions in people of Northern European descent, makes the gut absorb too much iron, and men usually show signs earlier than women. For this reason, men should not take high-dose iron without a blood test that shows they need it.
What is a normal iron level for women and men?
A single "iron value" does not exist. Doctors combine several blood markers:
| Marker | What it shows | Typical threshold (adults) |
|---|---|---|
| Ferritin | Size of your iron stores | Below 15 µg/L means deficiency (WHO); many labs and doctors act below 30 µg/L |
| Haemoglobin | Whether anaemia is present | Anaemia below 120 g/L in women, 130 g/L in men, 110 g/L in pregnancy (WHO) |
| Transferrin saturation | Iron available for transport | Low values point to iron deficiency; high values can point to iron overload |
| CRP | Inflammation | Infection or inflammation raises ferritin and can hide a deficiency |
Reference ranges differ between laboratories, and ferritin is usually higher in men and after menopause. Ask your doctor to explain your own results rather than comparing them with a table online.
Which foods are high in iron?
Iron comes in two forms. Haem iron in meat, liver and fish is absorbed well. Non-haem iron in plants, eggs and fortified foods is absorbed less well and depends strongly on the rest of the meal. The US Institute of Medicine estimates that vegetarians may need up to 1.8 times as much iron as people who eat meat.
| Food | Iron per 100 g (approx.) |
|---|---|
| Pumpkin seeds | 8.8 mg |
| Oat flakes | 4.3 mg |
| White beans, cooked | 3.7 mg |
| Spinach, cooked | 3.6 mg |
| Lentils, cooked | 3.3 mg |
| Chickpeas, cooked | 2.9 mg |
| Dried apricots | 2.7 mg |
| Beef, cooked | 2.6 mg |
| Eggs | 1.8 mg |
How to absorb more iron from plant foods
- Add a source of vitamin C to the meal: peppers, citrus fruit, berries or a squeeze of lemon. Vitamin C increases iron absorption.
- Drink coffee and black tea between meals rather than with them; their polyphenols reduce iron uptake.
- Soaking, sprouting and fermenting (sourdough, tempeh) lower phytate in grains and legumes.
- Large amounts of calcium in the same meal also reduce iron absorption, so spread calcium-rich foods and supplements across the day.
Vegans should plan iron together with the other critical nutrients of a plant-based diet; see vitamin B12 deficiency signs and our partner article on what iodine does for your body. If you train a lot, vegan nutrition for athletes covers iron needs in sport.
Signs of iron deficiency
Early iron deficiency often has no clear symptoms. As stores empty, you may notice:
- tiredness, weakness and lower exercise capacity;
- pale skin and inner eyelids;
- shortness of breath or a racing heart on exertion;
- headaches, poor concentration and feeling cold;
- brittle nails, hair shedding, cracks at the corners of the mouth;
- restless legs or cravings for ice (pica).
None of these signs proves iron deficiency. Thyroid problems, vitamin B12 or folate deficiency and many other conditions look similar, so a blood test is the only reliable way to know.
Should you take an iron supplement?
Take a dedicated iron supplement only when a blood test shows you need it, and follow the dose your doctor gives you. High-dose iron can cause constipation, nausea and stomach pain. Studies in young women with low iron stores found that taking iron on alternate days was absorbed as well as, or better than, daily doses, because each dose raises the iron-regulating hormone hepcidin for about a day. Your doctor will decide the dose and rhythm, and also checks whether the cause, such as heavy periods, needs attention. Keep all iron products out of reach of children: an overdose is dangerous for them.
Iron in Sanbera formulas
The two daytime formulas contain iron; the Nightly Reload formulas do not. Per daily serving of three tablets, Daily Essential Women provides 7 mg of iron (50 % NRV) and Daily Essential Men 3.5 mg (25 % NRV), reflecting the different needs of women and men. Both also contain vitamin C (Women 43.1 mg, 54 % NRV; Men 51.8 mg, 65 % NRV), which increases iron absorption, and vitamin A, which contributes to normal iron metabolism. Iron contributes to normal oxygen transport in the body and to the reduction of tiredness and fatigue. These are moderate, multivitamin-level amounts that complement a balanced diet; they are not designed to correct a diagnosed deficiency. If you have haemochromatosis or already take an iron product, speak to your doctor first.
Frequently asked questions
How much iron does a woman need per day?
Women need 16 mg of iron a day before menopause and 14 mg afterwards, according to the 2023 D-A-CH reference values. In pregnancy the need rises to 27 mg, and after birth it is 16 mg. Women who do not menstruate, for example because they take the pill continuously, need about 11 mg, the same as men. These figures apply to healthy people eating a mixed diet.
What is iron good for in the body?
Iron is needed to make haemoglobin and myoglobin, which carry and store oxygen. It contributes to normal oxygen transport, normal energy-yielding metabolism, normal cognitive function, the normal function of the immune system and the reduction of tiredness and fatigue. Without enough iron, the body produces fewer and smaller red blood cells, which can lead to iron deficiency anaemia.
What is a normal ferritin level for women?
Laboratory reference ranges for women are often about 15 to 150 µg/L, but they vary between labs. The WHO defines iron deficiency in healthy adults as ferritin below 15 µg/L, and many doctors regard values below 30 µg/L as low stores. Inflammation raises ferritin, so it is usually read together with CRP and haemoglobin.
Why should iron be taken with vitamin C and not with coffee?
Vitamin C keeps plant iron in a form the gut can absorb, so it increases iron absorption from the same meal. Coffee and black tea contain polyphenols that bind iron and can reduce absorption considerably. If you take an iron supplement, take it with water or orange juice and wait about an hour before your coffee, unless your doctor advises otherwise.
Can men take too much iron?
Yes. Men need only 11 mg a day and lose little iron, so extra iron from high-dose supplements can build up over years. People with hereditary haemochromatosis absorb too much iron even from food. Iron overload can damage the liver, heart and joints, which is why men should take iron supplements only after a blood test shows a deficiency.
Sources
- German Nutrition Society (DGE): Reference values for iron (2023)
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2015): Scientific opinion on Dietary Reference Values for iron
- World Health Organization (2020): WHO guideline on use of ferritin concentrations to assess iron status
- National Institutes of Health, Office of Dietary Supplements: Iron, Health Professional Fact Sheet
- European Commission: EU Register of nutrition and health claims
This article is for general information and does not replace advice from a doctor or pharmacist. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle.