Exhausted but Iron Looks Fine? Check Your Ferritin

Exhaustion, brain fog, and the desire to chew ice are signs your iron levels may be low—even if they look normal. Time to check in on this overlooked protein.

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Sabrina Cuevas didn’t think much of her new habit at first. She’d stop at the gas station, fill a few cups with ice, and chew her way through them during the day. Then it became four or five cups, every day, and people started calling her the Ice Lady.

The craving, it turned out, was a symptom. Ice chewing, called pagophagia, is sometimes an overlooked sign of iron deficiency.

With it came crushing fatigue, weight gain, and a fog she couldn’t shake. “Everything was a chore,” she said. However, when she went to the doctor, her labs came back “perfect.” Her iron levels were in range. Her thyroid looked fine.

It wasn’t until a gynecologist ordered a test that most patients never hear about that she got a clearer picture. A ferritin test revealed 4 nanograms per milliliter—a level many specialists consider dangerously low.

Ferritin, a protein that stores iron in the body, is often the first to fall when iron levels dip. Yet it’s rarely part of routine testing. For many patients, that gap can mean months or even years of debilitating symptoms before the cause is identified.

When Symptoms Show Up Before the Labs

For many patients, the first sign that something is wrong isn’t in the bloodwork. It’s in how they feel. Sabrina had exhaustion and brain fog. For others, it could be noticing more hair in the shower drain, feeling winded climbing stairs, or struggling to finish a workout.

Standard blood tests often miss the early stages of a condition because they measure only what’s circulating in the bloodstream, not what’s stored in reserve. Those stores are where iron deficiency usually begins.

Iron deficiency and anemia are often confused, but they’re not the same. Deficiency comes first, as the body’s iron reserves decline. Anemia develops later, when there isn’t enough iron left to produce healthy red blood cells. That delay is why many people experience symptoms for months while their lab results appear normal.

A 2024 study in JAMA Network Open found that nearly 30 percent of U.S. adults had signs of iron deficiency, without anemia or other major health issues. Some had low iron stores, while others had enough iron on paper but couldn’t access it properly, often due to inflammation. The researchers called the situation a “common public health problem” and urged better screening strategies.

“Symptoms can present well before the development of anemia,” Dr. George Goshua, a hematologist at Yale School of Medicine, told The Epoch Times in an email.

How quickly symptoms show up can vary. Some people feel depleted with only moderately low ferritin, while others tolerate lower levels for longer. Without routine screening, these early warning signs are easy to miss.

Your Iron Savings Account

Ferritin is the body’s way of storing iron—a kind of savings account tucked away in tissues such as the liver, spleen, and bone marrow. While the bloodstream uses iron daily for tasks such as oxygen delivery and energy production, ferritin provides backup for times of higher demand, such as during menstruation, illness, or growth.

“Ferritin provides a reservoir to store iron in your body,” Doug Corrigan, a biochemist and molecular biologist, wrote to The Epoch Times. “When iron is needed, ferritin releases some. When iron levels are too high, ferritin sequesters and holds onto it.”

If serum iron is like your checking account, ferritin is your savings. When savings run low, the body has nothing left to draw from, even if the checking account still looks fine.

Ferritin also acts as a safeguard. Free-floating iron can be toxic and trigger damaging oxidative stress in tissues, Corrigan said. Each ferritin complex can store up to 4,500 iron ions, acting as a biological safe, locking iron away until the body needs it, and preventing the cellular damage that free iron can cause.

What’s ‘Normal’ Isn’t Always Healthy

Even when ferritin is tested, results can be misleading. Most labs set the lower limit of normal around 15 to 20 nanograms per milliliter, a range based not on optimal health, but on population averages. Many people included in those averages were iron-deficient.

“There is no physiologic reason that ranges of normal serum ferritin should differ between men and women,” hematologists Kylee Martens and Thomas DeLoughery wrote in an article on ferritin published in Hematology. “Rather, this reflects the fact that many women have little to no total body iron stores.”

One large study found that if 50 nanograms per milliliter were used as the cutoff, nearly half of women under 50 would be classified as iron deficient, more than triple the rate seen in men at this level. That gap suggests women’s “normal” ferritin levels may reflect chronic, unrecognized deficiency rather than a true baseline.

In other words, women aren’t supposed to run on empty—they’ve just been measured that way.

Newer research suggests the bar should be higher. Studies show that symptoms such as fatigue often begin to improve once ferritin levels reach 50. Iron absorption doesn’t fully rebound until stores are restored to that range.

A recent analysis of more than 24,000 healthy adults found that early changes in red blood cell health began when ferritin dropped below 100, and were most noticeable between 50 and 65 nanograms per milliliter. These findings support what many clinicians already see in practice: People often feel better when their ferritin levels are closer to 50.

That number—50 nanograms per milliliter—isn’t arbitrary. An international panel of medical experts recently recommended using it as a reasonable starting point for identifying iron deficiency. They noted that below 50, subtle signs of deficiency, such as drops in red blood cell size and oxygen-carrying capacity, often emerge.

Yet a ferritin level of 18 is still commonly marked as “normal,” even when a patient is clearly having symptoms.

“There is no universally accepted standardized ‘normal’ range,” Goshua said. That ambiguity means many cases of deficiency remain hidden in plain sight.

Ferritin levels can also be misleading in the opposite direction. While low ferritin is a strong indicator of iron deficiency, normal or even elevated levels don’t always rule it out. Inflammation, infection, liver disease, and certain cancers can push ferritin higher, masking a true deficiency.

“You can’t rule out iron deficiency if ferritin levels are normal,” Corrigan said. “Ferritin may be elevated due to one of these other causes, like inflammation.”

Why Iron Deficiency Often Slips Through the Cracks

Iron deficiency is among the most common and underdiagnosed health issues, particularly in women. Yet in the United States, there are still no official guidelines recommending routine ferritin screening for women of reproductive age, a gap that leaves many symptoms unexplained and untreated.

Even among pregnant women, who face heightened iron demands, screening isn’t standard. In 2024, the U.S. Preventive Services Task Force concluded there wasn’t enough evidence to recommend for or against screening for iron deficiency in asymptomatic pregnancies.

The science isn’t in doubt. What lags are the systems needed to act on it. With outdated lab standards and inconsistent symptom recognition, there is often uncertainty around how to treat low iron without anemia.

That’s assuming the test is run at all. Without formal guidelines, ferritin is often checked only in obvious cases such as anemia or heavy bleeding. Women with vague but persistent symptoms may never receive the full workup.

“There are a slew of issues that need to be addressed,” Goshua said. Among them, he said, are the need to standardize ferritin reference ranges and dispel lingering myths about iron treatment. Those changes, he said, “do not even touch issues of concern around cost.”

Yet cost may argue in favor of better screening. In a recent study published in the American Journal of Hematology, Goshua and colleagues modeled the impact of testing ferritin at different thresholds. Screening at 25 nanograms per milliliter—instead of waiting until levels drop to 15—was more effective and cost-efficient, yielding better outcomes at a relatively low price.

“Put another way,” Goshua said, “our study does not say that 25 mcg/L is the threshold for ID diagnosis, but rather that 25 mcg/L is the cost-effective threshold, as compared to 15 mcg/L.”

However, identifying the right threshold is only part of the challenge. While ferritin is one of the best tools for spotting iron deficiency, it isn’t perfect. Levels can appear normal even when iron stores are low, especially if someone has inflammation or another health condition. Plus, ferritin results can vary between labs, making it harder to get a clear answer. That’s why doctors say it’s important to look at symptoms and risk factors, not just numbers on a test.

Still, many clinicians believe the true threshold for well-being is even higher. Even modest shifts in screening could detect iron deficiency earlier and prevent a long chain of avoidable consequences.

A global effort is underway to catch up. In 2024, the American Society of Hematology convened its first international panel to define diagnostic criteria for iron deficiency using the most rigorous scientific methods available. Recommendations, including those for reproductive-age women, are expected by late 2025 and could mark a turning point for how iron health is measured and managed.

Still, not everyone agrees about where the line should be drawn. Some experts warn that setting ferritin cutoffs too high could lead to overdiagnosis, identifying people who may never develop symptoms or need treatment.

What Can You Do About It?

If your ferritin levels come back low, replenishing iron is only part of the solution. The more pressing question is: Why are your stores depleted in the first place?

For many women, the answer lies in heavy menstrual bleeding, which can lead to gradual but chronic iron loss. Others may struggle with poor absorption due to conditions such as celiac disease or inflammatory bowel disease. Regular blood donation or intensive athletic training can also outpace the body’s ability to restore its iron supply.

Treatment typically starts with oral iron supplements but is not always straightforward. Some people don’t absorb iron pills well. Others stop taking them because of side effects such as nausea, constipation, or stomach pain.

In cases where pills aren’t effective, or when ferritin remains stubbornly low, intravenous iron may be used instead. It bypasses the digestive system and restores levels more quickly, though it’s typically reserved for more severe deficiencies.

Dietary changes can help support recovery. Heme iron, found in red meat, poultry, and shellfish, is absorbed more easily than the non-heme iron in plant foods such as spinach or lentils. Pairing iron-rich foods with vitamin C, such as citrus or bell peppers, helps absorption. Coffee, tea, and calcium can block it.

Restoring iron stores takes time, often several months or even years, and symptoms may lag behind the lab results. However, the difference, for many, is profound.

“I feel like myself again,” said Cuevas, whose fatigue began to lift after a few weeks of iron therapy. “I didn’t realize how bad it had gotten until I started feeling better.”