Feeling sluggish? Get your iron – and ferritin – checked

Have you been tired, weak or short of breath? You might have heard low iron could be the cause, but there’s another factor to monitor, too: ferritin. While the two are related, they aren’t the same thing.

What is iron?

Iron is a mineral your body needs to make hemoglobin, the protein in red blood cells that carries oxygen. When iron levels are low, your body can’t transport oxygen as well, which can make you feel run-down. Symptoms of low iron may include:

• Ongoing fatigue
• Weakness
• Shortness of breath
• Dizziness or headaches
• Pale skin

What is ferritin?

Ferritin is a protein that helps build iron stores for your body. Your ferritin level shows how much iron you have saved, even before your iron levels drop. Symptoms of low ferritin may include:

• Fatigue that doesn’t improve with rest
• Hair thinning or hair loss
• Brittle nails
• Brain fog or trouble concentrating
• Restless legs, especially at night

“Low ferritin helps us see iron deficiency earlier, before it turns into anemia,” says Dr. Sivakami Thayu, an internal medicine provider at Advocate Health Care. “That gives us a chance to intervene sooner.”

When to get tested

Ask your provider about getting a blood draw for a CBC, or complete blood count, to check your ferritin and iron levels if you:

• Feel tired for weeks with no clear reason
• Have heavy menstrual periods
• Are pregnant or recently postpartum
• Follow a vegetarian or vegan diet
• Have digestive conditions that affect absorption
• Don’t improve after taking iron supplements

What your blood levels mean

• Low ferritin, normal iron: Your body doesn’t have enough iron in storage. This is called iron deficiency. It can be caused by inflammation, chronic disease, blood loss or not getting enough iron from your diet.
• Normal ferritin, low iron: You may have functional iron deficiency, which means iron is present in your body but not readily available for use. This can result from illness, inflammation, a lack of iron in your diet or issues with your body absorbing iron.
• Low ferritin, low iron: You may be on your way to developing iron-deficiency anemia. This is a condition where you’re lacking healthy red blood cells to deliver oxygen throughout your body.

“Iron and ferritin are two pieces of the same puzzle,” Dr. Thayu says. “The bottom line is that ferritin shows your iron reserves, and iron indicates what’s circulating in your bloodstream.”

She emphasized that while symptoms like fatigue, dizziness or hair loss can be worrisome, a simple test can determine if your iron levels are the culprit.

How do you fix low iron or ferritin?

The good news is iron deficiency and depletion – and even sometimes anemia – are relatively easy to treat. Here’s how:

• Fit iron-rich foods into your diet: Meat and seafood are great sources of iron, while the iron in plants such as legumes, leafy greens, nuts and whole grains requires a little more effort for your body to absorb. Citrus and berries can enhance absorption, so try out new food combinations to help increase your levels.
• Take supplemental iron: Your doctor may also suggest an iron supplement to boost your iron stores. Ask which type of iron is best for you. Some forms can upset your stomach, but slow-release formulas can help.
• Get an iron infusion: If supplements haven’t meaningfully increased your iron or ferritin levels, your doctor might recommend an iron infusion instead. They’ll place an IV (catheter) in your vein to inject a fluid iron supplement into your bloodstream. This is the fastest way to treat severe deficiency.

“Understanding your iron and ferritin levels isn’t just about numbers – it’s about your energy, focus and quality of life,” says Dr. Thayu. “The sooner we identify the cause, the sooner we can help you feel better.”

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