Iron is a mineral that helps red blood cells carry oxygen from the lungs to cells all over the body.

Updated: June 3, 2019

Iron is a mineral. Most of the iron in the body is found in the hemoglobin of red blood cells and in the myoglobin of muscle cells. Iron helps red blood cells carry oxygen from the lungs to cells all over the body. It  is needed for transporting oxygen and carbon dioxide. It also has other important roles in the body. Iron can be found in foods like meat, fish, tofu, beans, spinach, cereal and other foods. Iron is most commonly used for preventing and treating anemia caused by low iron levels. It is also used for anemia caused by menstrual cycle related bleeding, pregnancy, kidney problems or heart failure.

Dietary Sources:

Include Iron-rich foods in your diet, such as:

  •     Red meat, pork and poultry
  •     Dark green, leafy vegetables, such as spinach and kale
  •     Dried fruit, such as raisins and apricots
  •     Peas, beans and other pulses
  •     Seafood
  •     Iron-fortified foods
  •     Seeds and nuts

Eating vitamin C will help your body absorb iron better. Therefore, make sure you eat enough vitamin C-rich foods, such as fruits and vegetables.
It may also be beneficial to avoid certain foods that can inhibit iron absorption when eaten in large amounts. These include tea and coffee and foods high in calcium such as dairy products and whole-grain cereals.


Common causes of iron deficiency include inadequate iron intake due to poor diet or restrictive diets, inflammatory bowel disease, increased requirements during pregnancy and blood loss through heavy periods or internal bleeding. Iron deficiency occurs when the body doesn't have enough of the mineral iron. This leads to abnormally low levels of red blood cells. That is because iron is needed to make hemoglobin, a protein in red blood cells that enables them to carry oxygen around the body.
If your body doesn't have enough hemoglobin, your tissues and muscles won't get enough oxygen and be able to work effectively. This leads to a condition called anemia. Iron deficiency can result in symptoms such as poor health, concentration and work productivity that can affect your quality of life.
Signs and symptoms of iron deficiency vary depending on the severity of the anemia, how quickly it develops, your age and current state of health. Extreme fatigue, weakness, pale skin, chest pain, fast heartbeat or shortness of breath, headache, dizziness or lightheadedness, cold hands and feet, inflammation or soreness of your tongue, brittle nails, unusual cravings for non-nutritive substances, such as ice, dirt or starch are some of the symptoms of iron deficiency. Eating iron-rich foods can help in deficiency of iron. You may also need to take iron supplements as well to rebuild iron stores in your body.

Uses & Effectiveness:

Effective for:

Anemia caused by chronic conditions:

Anemia can be caused by many diseases such as cancer, kidney problems, or heart problems. Taking iron along with other medications such as epoetin alfa can help build red blood cells and prevent or treat anemia in people with kidney problems or being treated for cancer with chemotherapy. Receiving iron by injection is more effective than taking iron by mouth.

Anemia caused by low iron levels:

Taking iron by mouth or by injection is effective for treating and preventing anemia caused by too little iron in the body.

Low iron levels during pregnancy:

Taking iron by mouth might reduce the risk of anemia caused by too little iron in the body when taken by women who are pregnant.

Possibly Effective for:

Coughs caused by ACE inhibitors:

Medications used for high blood pressure called ACE inhibitors can sometimes cause coughing as a side effect. Taking iron by mouth might reduce or prevent this side effect. The ACE inhibitor medications include captopril (Capoten), enalapril (Vasotec), lisinopril (Prinivil, Zestril), and many others.

Heart failure:

People who have heart failure also have low levels of iron in few cases. Giving iron by injection can improve symptoms of heart failure such as the ability to exercise and other symptoms.

Restless legs syndrome (RLS):

Taking iron by mouth decreases symptoms of RLS such as leg discomfort and sleep problems. In fact, taking iron to improve symptoms is recommended for people with RLS and low iron levels. Some people with RLS also have improved symptoms after having iron injected into the vein (by IV). But it is unknown if all forms of iron work when given by IV.

Improving thinking:

Taking iron by mouth might help improve thinking, learning, and memory in children ages 6-18 years with low levels of iron. Alao, taking iron might improve attention in girls ages 13-18 with unknown iron status.

Possibly Ineffective for:

Preterm labor:

Taking iron during pregnancy starting in the second trimester doesn't seem to increase the duration of pregnancy or increase the weight of the infant at birth.

Insufficient Evidence for:


Taking iron by mouth for 1-3 months improves some symptoms of attention problems in children with a condition called attention deficit-hyperactivity disorder (ADHD) and low iron levels.

Breath-holding attacks:

Taking iron by mouth or through a shot reduces the number of breath-holding attacks in children.

Esophageal cancer or Cancer of the tube that connects the throat and stomach:

People who take iron supplements are 32 percent less likely to develop one type of esophageal cancer.

Stomach cancer:

People who take iron supplements are about 1.6 times more likely to develop one type of stomach cancer.


Taking iron as ferrous sulfate might improve unexplained fatigue in women.

Anemia in people with HIV:

Children with HIV and anemia who take iron along with a multivitamin for 3 months have a lower chance of still having anemia 3 months later compared to children who take only a multivitamin.

Child development:

Iron does not improve thinking or learning in infants and children who do not have anemia. However, there might be an improvement in movement skills. Taking iron does not increase growth in children.

Physical performance:

Taking iron by mouth can improve the ability to exercise in younger women and children.
More evidence is needed to rate iron for the below uses:  

  •     Canker sores.
  •     A digestive tract disease called Crohn's disease.
  •     Depression.
  •     Female infertility.
  •     Heavy menstrual bleeding.
  •     Other conditions.

Side Effects & Safety:

Iron is likely safe for most people when it is taken by mouth or injected into the vein in appropriate amounts. However, it can cause side effects such as stomach upset and pain, constipation or diarrhea, nausea, and vomiting. Taking iron supplements with food seems to reduce some of these side effects. However, food can also reduce how well the body can absorb iron. Iron is absorbed the best on an empty stomach. If it causes too many side effects, it can be taken with food. Try to avoid taking iron with foods containing dairy products, coffee, tea, or cereals. You should wait at least 2 hours after having these foods before taking your iron supplements.
There are many forms of iron products such as ferrous sulfate, ferrous gluconate, ferrous fumarate, and others. Some products, such as those containing polysaccharide-iron complex (Niferex-150, etc), may cause fewer side effects than others. Some enteric coated or controlled release iron products might reduce nausea for some people. However, the body may not be able to absorb these products as well.
Taking a vitamin C supplement or drinking orange juice with your iron pill can help the iron absorb into your body. Liquid iron supplements may blacken teeth. High doses of iron are likely unsafe, especially for children. Iron is the most common cause of poisoning deaths in children. Doses as low as 60 mg/kg can be fatal. Iron poisoning can cause many serious problems including stomach and intestinal distress, liver failure, dangerously low blood pressure, and death. If you suspect an adult or child has taken more than the recommended amount of iron, call your healthcare professional or the nearest poison control center immediately.
High intake of iron might increase the chance of developing heart disease. People with high intake of iron, especially from food sources such as red meat, are more likely to have heart disease. This may be especially true for people with type 2 diabetes. But this is controversial.

Special Precautions & Warnings:

Pregnancy and breast-feeding:

Iron is likely safe for pregnant and breast-feeding women who have enough iron stored in their bodies when used in doses below the tolerable upper intake level (UL) of 45 mg per day of elemental iron. The UL is the highest level of intake at which no harmful side effects are expected. However, iron is likely unsafe when taken by mouth in high doses. If you do not have iron deficiency, do not take more than 45 mg per day of elemental iron. Higher doses cause stomach and intestinal side effects such as nausea and vomiting. Higher doses of iron may also cause high levels of hemoglobin in the blood. High hemoglobin levels at the time of delivery are associated with bad pregnancy outcomes.

Premature infants:

Giving iron to premature infants with low blood levels of vitamin E can cause serious problems. Low levels of vitamin E should be treated before giving iron. Talk with your healthcare provider before giving iron to a premature infant.


There is concern that a diet that is high in iron might increase the risk of heart disease in women with type 2 diabetes, although this has not been proven. If you have diabetes, discuss your iron intake with your healthcare provider.

Stomach or intestinal ulcers:

Iron might cause irritation and make these conditions worse. Use iron with care.

Intestinal inflammation, such as ulcerative colitis or Crohn's disease:

Iron might cause irritation and make these conditions worse. Use iron with care.

Hemoglobin diseases:

Taking iron might cause iron overload in people with these conditions. If you have a hemoglobin disease, do not take iron unless directed by your healthcare provider.


Be cautious with the below combination as these can have moderate interaction:

Antibiotics (Quinolone antibiotics) interacts with Iron:

Iron might decrease the amount of absorbtion of antibiotic in the body. Taking iron along with some antibiotics might decrease the effectiveness of some antibiotics. To avoid this interaction take iron two hours before or two hours after taking antibiotics.
Some of these antibiotics that might interact with quercetin include ciprofloxacin (Cipro), enoxacin (Penetrex), trovafloxacin (Trovan), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam) and grepafloxacin (Raxar).

Antibiotics (Tetracycline antibiotics) interacts with Iron:

Iron can attach to tetracycline antibiotics in the stomach and decrease how much tetracycline antibiotics the body can absorb. Taking iron along with tetracycline antibiotics might decrease the effectiveness of tetracycline antibiotics. To avoid this interaction take iron two hours before or four hours after taking tetracyclines. Some tetracycline antibiotics include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).

Bisphosphonates interacts with Iron:

Iron can decrease how much bisphosphate the body absorbs. Taking iron along with bisphosphates can decrease the effectiveness of bisphosphates. To avoid this interaction take bisphosphonate at least two hours before iron or later in the day. Some bisphosphonates include alendronate (Fosamax), tiludronate (Skelid), etidronate (Didronel), risedronate (Actonel) and others.

Levodopa interacts with Iron:

Iron might decrease how much levodopa the body absorbs. Taking iron along with levodopa might decrease the effectiveness of levodopa. Do not take iron and levodopa at the same time.

Levothyroxine interacts with Iron:

Levothyroxine is used for low thyroid function. Iron can decrease how much levothyroxine the body absorbs. Taking iron along with levothyroxine might decrease the effectiveness of levothyroxine. Armour Thyroid, Eltroxin, Levo-T, Levothroid, Levoxyl, Estre, Euthyrox, Synthroid, Unithroid, and others are some brands that contain levothyroxine.

Methyldopa (Aldomet) interacts with Iron:

Iron can decrease how much methyldopa (Aldomet) the body absorbs. Taking iron along with methyldopa (Aldomet) might decrease the effectiveness of methyldopa (Aldomet). To prevent this interaction take iron at least two hours before or after taking methyldopa (Aldomet).

Mycophenolate Mofetil (CellCept) interacts with Iron:

Iron might decrease how much mycophenolate mofetil (CellCept) the body absorbs. Taking iron along with mycophenolate mofetil (CellCept) might decrease the effectiveness of mycophenolate mofetil (CellCept). To avoid this interaction take iron at least two hours after mycophenolate mofetil (CellCept).

Penicillamine (Cuprimine, Depen) interacts with Iron:

Penicillamine is used for Wilson's disease and rheumatoid arthritis. Iron might decrease how much penicillamine your body absorbs and decrease the effectiveness of penicillamine. To avoid this interaction take iron two hours before or two hours after taking penicillamine.
Be watchful with the below combination as these can have minor Interaction:

Chloramphenicol interacts with Iron:

Iron is important for producing new blood cells. Chloramphenicol might decrease new blood cells. Taking chloramphenicol for a long time might decrease the effects of iron on new blood cells. But most people only take chloramphenicol for a short time so this interaction isn't a big problem.


The following doses have been studied in scientific research and is recommended.


By Mouth:

For anemia caused by low iron levels:

50-100 mg of elemental iron three times daily for 3 months up to 6 months. Doses between 30-120 mg weekly have been used in adult women.

For preventing anemia cause by low iron levels in pregnancy:

20-225 mg of elemental iron daily have been used. The recommended dose is 45 mg daily.

For restless legs syndrome:

Iron as ferrous sulfate has been taken at doses of 325 mg twice daily for 12 weeks.

For cough caused by ACE inhibitor medications:

256 mg of ferrous sulfate daily has been used.

Injected Into The Vein:

For anemia caused by chronic conditions:

A total dose of 2232 mg of iron given by injection delivered over 6 months to 1020 mg given by IV over 1 week have been used.

For heart failure:

Iron as ferric carboxymaltose has been given by injection at doses of 200 mg weekly until iron levels are normal, followed by 200 mg by injection every month for 6 months.


By Mouth:

For anemia caused by low iron levels:

4-6 mg/kg of iron per day divided into three doses for 3 months up to 6 months.

For preventing low iron levels:

The American Academy of Pediatrics recommends iron supplements for some children at risk of low iron levels.

For breast-fed infants:

1 mg/kg/day elemental iron from ages 4-6 months.

For Infants 6-12 months:

11 mg/day of iron from food or supplements.

For pre-term infants:

2 mg/kg/day of iron for the first year until the baby is switched to formula or getting enough iron from food sources.

For toddlers aged 1-3 years:

7 mg daily of iron f not getting enough iron from food sources.

For improving learning and thinking skills in children and adolescents with anemia caused by low iron levels:

650 mg ferrous sulfate twice daily.
The adequate intake (AI) of iron for infants 6 months of age and less is 0.27 mg/day. For older infants and children, the recommended daily allowances (RDAs) for iron are:

  • Infants 7 to 12 months, 11 mg/day
  • children 1 to 3 years, 7 mg/day
  • 4 to 8 years, 10 mg/day
  • 9 to 13 years, 8 mg/day
  • boys 14 to 18 years, 11 mg/day
  • girls 14 to 18 years, 15 mg/day.
  • For adults, the RDA for iron is 8 mg/day for men ages 19 and older and women ages 51 and older.
  • For women 19 to 50 years, the RDA is 18 mg/day.
  • For pregnant women, the RDA is 27 mg/day.
  • For breast-feeding women, the RDA is 10 mg/day for ages 14 to 18 years, and 9 mg/day for ages 19 to 50.

Tolerable Upper Intake Levels (UL), the highest intake at which no unwanted side effects are expected, for iron are:

  • infants and children birth to age 13, 40 mg/day
  • people age 14 and older (including pregnancy and breastfeeding), 45 mg/day.

UL recommendations do not apply to people under medical supervision for iron deficiency.

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