Common Symptoms of Iron Deficiency Anemia — and Why They Can Be Hard to Spot

Certain groups, including pregnant people and athletes, can be at a higher risk. 

You may have seen more chatter on the internet about ferritin (iron stores) or iron deficiency — particularly among women and athletes — but experts say that true iron deficiency anemia remains “underrecognized and underdiagnosed,” largely because its symptoms can look like so many other things… or nothing at all. Some of the more common signs of iron deficiency anemia (such as fatigue and headaches) can be brushed aside as “just life,” especially for the groups with a higher risk, including pregnant women, people with heavy periods, people who experience chronic bleeding, or endurance athletes. 

So, what do symptoms of iron deficiency anemia actually look like, and how can you know if you’re low on iron? Everything you need to know about what iron deficiency feels like, causes, and what to do about it, here.  

TL;DR

Symptoms of iron deficiency anemia range from early, easy-to-miss signs — unexplained fatigue, headaches, dizziness, heart palpitations, and brain fog — to later ones like pale skin, restless legs, brittle nails, hair shedding, and unusual cravings. Mild cases often go unnoticed, so don’t try to self-diagnose: if you have symptoms, see a doctor for a blood test. It’s important that you confirm that your iron levels are low with a blood test before trying to take an iron supplement, because too much iron can be harmful. 

Key Takeaways

• Common symptoms of iron deficiency anemia are fatigue, weakness, headaches, dizziness, heart palpitations, and brain fog from your blood’s reduced ability to carry oxygen throughout your body. 
• As anemia worsens, symptoms can also include pale or yellow-ish skin, shortness of breath, restless legs, brittle nails, hair shedding, and cravings for ice.
• People who have heavy periods, are pregnant, follow plant-based diets, are athletes, or who have certain gastrointestinal disorders may be at a higher risk.
• If you have any symptoms, a doctor can run a blood test and diagnose you, plus recommend treatment depending on the cause.

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What Iron Deficiency Anemia Is

Anemia is a condition where you have fewer red blood cells or less hemoglobin than normal, reducing your body’s ability to carry oxygen. Hemoglobin is a protein in red blood cells that carries oxygen from your lungs to the rest of your body. 

Iron deficiency anemia is the most common cause of anemia, and happens when your body doesn’t have enough iron, an essential mineral that your body uses to make hemoglobin. It’s typically caused by blood loss, low iron intake, trouble absorbing iron, or increased iron needs (such as during pregnancy) — all of which can leave your body without sufficient iron to make enough hemoglobin. 

Your body doesn’t make iron on its own, so you need to get it from outside sources. Iron is found in a variety of foods, including lean meats, seafood, poultry, some beans, lentils, spinach, nuts, and fortified foods, but your body only absorbs a small fraction of the iron you ingest. Iron binds to a specialized protein called ferritin, which stores the iron in your body and releases it when you need it to make new red blood cells. 

Keep in mind, it’s possible to be deficient in iron without having iron deficiency anemia. Iron deficiency progresses to anemia when your body is unable to support normal hemoglobin production. Iron deficiency is recognized as one of the most common nutrient deficiencies in the world, and a 2025 study estimated that somewhere between 5.9 million and 9.2 million non-pregnant adults in the U.S. had iron deficiency anemia, depending on the diagnostic cutoff used.

The Symptoms of Iron Deficiency Anemia

You may have no symptoms at all if your anemia is mild, or they may be subtle at first and develop slowly, according to the National Institutes of Health (NIH). Some of the earlier symptoms of iron deficiency anemia include:

• Fatigue: Feeling weaker or more tired than usual, day-to-day or during exercise.
• Headaches: Chronic headaches or headaches triggered by activity. 
• Dizziness or lightheadedness: Potentially triggered by standing up.
• Heart palpitations: A pounding, racing, fluttering, or rapid heart beat.
• Brain fog: Problems concentrating or thinking. 

As anemia worsens and your iron levels lower, additional symptoms may show up. Other possible symptoms include:

• Being pale or having yellow “sallow” skin
• A blue color to the whites of the eyes
• Shortness of breath or chest pain, especially with physical activity
• Pounding or “whooshing” in the ears
• Craving for ice, clay, or other non-food things (aka “pica”)
• A sore, smooth, or irritated tongue
• Mouth ulcers
• Brittle nails
• Poor sleep
• Cold intolerance, or cold hands or feet
• Restless leg syndrome
• Hair loss

What Causes It (and Who’s Most at Risk)

Iron deficiency anemia hinges on not having enough iron in your body — but it’s not only about how much iron you eat. Your body can only absorb a small portion of the iron you ingest, and other factors can affect how much iron your body needs, how much it can use, and how much it’s losing. 

Some common causes of iron deficiency anemia include blood loss (whether from heavy periods or bleeding disorders), low dietary iron intake, or poor iron absorption (potentially due to gastrointestinal diseases). 

These are some groups that are at a higher risk of iron deficiency anemia:  

• Vegetarians, vegans, and people with low-iron diets: Animal sources of iron are better absorbed than plant sources of iron, which is why plant-based eaters are at a higher risk.
• People with heavy periods: Heavy or prolonged menstrual bleeding is a major cause of iron deficiency, and can lead to iron deficiency anemia.
• People who are pregnant, post-partum, or breastfeeding: The need for iron increases during pregnancy, and deficiency can carry over to the postpartum period or be worsened by blood loss during delivery. A 2026 study analyzing national survey data from 2003 to 2023 estimated that 6.9 percent of pregnant people had iron deficiency anemia, while 52.9 percent had iron deficiency, including those without anemia.
• People who’ve undergone surgery: Specifically, gastric bypass or surgeries on the digestive tract, which can impact iron absorption, or surgeries that involve bleeding. 
• People with gastrointestinal diseases: Including celiac disease, Crohn’s disease, or  inflammatory bowel diseases such as ulcerative colitis which can cause hidden blood loss or malabsorption of iron.
• People with bleeding disorders: For example, those that lead to chronic nose bleeds or other blood loss.
• Athletes: Particularly endurance athletes, who may be deficient due to increased iron needs and losses (such as through sweat) and reduced absorption. 

When to See a Doctor

You might know someone who swears by iron supplements or is convinced they have iron deficiency based on symptoms alone, but don’t try to self-diagnose or treat iron deficiency anemia on your own. You should talk to your doctor if you’re experiencing any symptoms of iron deficiency. They can do a blood test to determine whether or not you have an iron deficiency, as well as help ID the potential cause and suggest the proper treatment. 

Contact a health professional right away if you notice blood or black tar-like appearance in your stool, and call 911 for sudden or persistent chest pain or trouble breathing.

Frequently Asked Questions

Jenna Congdon, RN, reminds patients, “It may be helpful to ask your doctor to check your ferritin levels as well as standard blood count labs so that iron deficiency without anemia — where you have low iron stores, indicated by low ferritin, but your hemoglobin levels appear normal — isn’t missed.”

Bottom Line on Iron Deficiency Anemia Symptoms

When iron deficiency progresses to iron deficiency anemia, it can show up with subtle symptoms like fatigue, headaches, or brain fog, but can include stranger signs like yellowed or pale skin, brittle nails, and weird cravings (among many other things). It’s good to know the signs — especially if you’re in an at-risk group, like pregnant people, plant-based eaters, athletes, or those with GI disorders — and talk to a doctor if you think you might be iron-deficient. They can suss out the cause and recommend proper treatment, whether that’s supplementation or something else.

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