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You may see iron supplements at the pharmacy or hear your doctor mention iron in your blood test results. What exactly is iron, and what does it do in your body? Iron is a mineral that helps red blood cells do their job. It plays a role in your immune system and the work of a few hormones, too.

Typically, your body gets iron from food. Naturally iron-rich foods include meat, eggs, some seafood, dark leafy greens, and beans. Manufacturers add it to some grain products, such as cereal and bread, too. You need a certain level of iron in your blood to stay healthy and feeling good.

What Iron Does in the Body

When you eat food that has iron in it, the mineral goes through your digestive tract, where your body absorbs it. From there, iron creates hemoglobin in your red blood cells. This important protein carries oxygen all over your body. Every time you take a breath, hemoglobin takes the oxygen from your lungs and transports it everywhere your body needs it. If your organs don’t  get the oxygen they need, it can leave you feeling tired, weak, and breathless.

For these reasons, your iron levels play a big part in your daily energy levels.

But that’s not all iron does. It has a job in the immune system, too. It plays an important role in how your body creates and spreads immune cells. So if your iron levels are low, you could be more prone to infections.

Iron also keeps your thyroid running at its best. Low iron can sometimes lead to thyroid problems.

How Much Iron Is Enough?

How much iron you need every day depends on a few things that are unique to each person, like your age or whether you are pregnant or breastfeeding. So it’s a good idea to ask your doctor how much iron you should try to get each day. 

How Do Doctors Check Iron?

Your doctor may check your iron levels as part of blood work during a regular physical. If you have symptoms of low iron, that could also prompt your doctor to run other tests.

Your doctor will generally start by checking your hemoglobin level. Good hemoglobin levels suggest you have enough iron in your blood. You’ll get your results in grams per deciliter. A normal hemoglobin level is generally:

  • Women: 12.1 to 15.1
  • Men: 13.8 to 17.2

Your doctor might also do a specific combination of iron tests including iron level, iron binding capacity, and a ferritin test to check your body's iron status. Ferritin is an iron-containing protein in your blood that allows your body to store iron you get from your diet. Generally, these test results come in micrograms per liter. Normal ferritin levels are:

  • Women: 11 to 307
  • Men: 24 to 336

What if Your Iron Is Low?

If your iron test comes back with below-normal levels and you have anemia, it could mean you have iron-deficiency anemia. Iron deficiency is one of many causes of anemia. Anemia causes multiple symptoms like low energy, headache, shortness of breath, and more.

If you find out your iron levels are low, talk to your doctor. The treatment for low iron depends on the cause, whether it’s your diet or another health condition causing the problem. Your doctor can most likely figure out what’s behind your low iron level. After that, you’ll get recommendations on how to bring your iron level up so that you can feel your best.

Show Sources

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Cleveland Clinic: “Iron in Your Diet,” “Low Hemoglobin,” “Anemia.”

National Institutes of Health, Office of Dietary Supplements: “Iron Fact Sheet For Consumers.”

Mayo Clinic: “Iron Deficiency Anemia,” “Ferritin Test.”

Johns Hopkins Medicine: “Iron-Deficiency Anemia.”

OneBlood: “How To Test For Low Iron.”

Mount Sinai: “Hemoglobin.”

Frontiers in Pharmacology: “Iron at the interface of immunity and infection.”

Harvard T.H. Chan School of Public Health: “Iron.”

National Library of Medicine: “Chronic anemia and thyroid function.”