Ferritin: what it is, why it is needed, and what its norms are

Do you wake up feeling tired, even after a long sleep? Have you noticed that your hair has lost its shine and started falling out, and your nails have become brittle? These symptoms are often attributed to stress, but for many women, they are the ones most at risk — the cause lies much deeper, at the level of iron deficiency.

Until recently, the “gold standard” for diagnosing anemia was based solely on hemoglobin levels. However, today medicine proves that normal hemoglobin is often just an illusion of well-being, behind which lies a latent (hidden) iron deficiency. This condition does not occur instantly — it is a long process of depletion of internal resources, which can be disguised for years as chronic fatigue syndrome or seasonal apathy. The key indicator of the true state of the “iron depot” is ferritin.

Why this protein is so important, how to correctly interpret test results, and why taking iron supplements on your own can be dangerous — endocrinologist Ksenia Marchenko explains.

Ksenia Marchenko

Adult Endocrinologist

• 8 years of experience

What is ferritin? Why is there so much talk about it today, and what does this indicator affect from a physiological point of view?

Ferritin is a protein that stores iron in the body, so ferritin and iron levels are always evaluated in relation to each other. Previously, attention was mainly paid to hemoglobin, that is, to what causes anemia. It is now understood that anemia is a late signal, and that iron deficiency can occur in the early stages, when hemoglobin is still normal. It is ferritin, and not an indicator such as the norm of iron in the blood, that allows you to detect early iron deficiency and prevent problems.

Ferritin (or rather, iron) affects:

Energy metabolism and muscle strength.

Iron is a component of enzymes that transfer energy in cells. Low ferritin leads to rapid fatigue, weakness, and decreased endurance.

Brain function and general well-being.

Iron deficiency impairs concentration, attention, memory, and mood.

Immunity.

Iron is necessary for the production of immune system cells. If a person has low ferritin, their body will be more susceptible to infections.

Recovery after bleeding, training, and menstruation.

Ferritin deficiency slows down recovery.

What is the normal range for ferritin for women and men? Do reference values ​​differ depending on age? Why do laboratory “norms” sometimes mislead patients?

The reference range is formed statistically, not clinically. The clinical optimum is higher. Various studies show this.

<30 ng/ml — clearly a deficiency of iron stores, even if hemoglobin is normal. A value of 30 ng/mL is considered normal. But some patients may still have iron-deficiency symptoms. Therefore, the optimal ferritin level today is considered to be 40–45 ng/mL (according to various sources)—better energy, less hair loss, higher tolerance to physical exertion, etc.

Here is a brief clinical conclusion from the article Re-evaluating ferritin thresholds to diagnose iron deficiency (Clinical Biochemistry, 2025):

Optimal ferritin values:

• 45 (ng/ml) and above for women
• 70 (ng/ml) and above for men

What are the causes of low ferritin?

The main causes of low ferritin are conditions in which the body loses iron, does not receive enough of it, or cannot absorb it:

1. Chronic blood loss: heavy or prolonged menstruation, blood loss from the gastrointestinal tract (gastritis, ulcers, polyps, hemorrhoids), donation, or postoperative conditions.
2. Increased need for iron: pregnancy and lactation, growth period in adolescents, and intense physical activity.
3. Insufficient intake with food, restrictive diets: vegetarianism/veganism without compensation — low intake of heme iron.
4. Impaired absorption of iron — gastritis, Helicobacter pylori, celiac disease, inflammatory bowel diseases, taking proton pump inhibitors, and antacids.

Does low ferritin always mean anemia? What other tests are needed to accurately diagnose anemia?

No, low ferritin levels do not indicate anemia.

Ferritin and anemia are related, but different concepts.

Anemia is a condition in which hemoglobin levels decrease (along with red blood cell count and hematocrit).

Very often, iron deficiency occurs in stages:

1. Depletion of iron stores — reduced ferritin, but normal hemoglobin — this is not anemia.
2. Latent iron deficiency — reduced ferritin, reduced transferrin saturation, hemoglobin may still be normal.
3. Iron deficiency anemia — reduced ferritin, reduced hemoglobin, changes in erythrocyte indices or hematocrit.

Therefore, in addition to ferritin, I always recommend a clinical blood test. Less often, the percentage of transferrin saturation.

Why does taking iron tablets frequently not help improve your levels?

Most often, this means that the real cause of low ferritin has not been identified.

Even the “perfect” drug will not help if you have:

• heavy menstruation
• gastrointestinal diseases
• regular blood donation
• chronic blood loss

Without correction of the cause, ferritin does not increase or fall rapidly.

Another reason why the ferritin level does not increase is due to improper iron intake:

• taking it with food
• at the same time as milk or dairy products, coffee, and tea
• a small dose of iron and an insufficient duration of treatment (anemia is treated on average for 3–6 months)

Why can self-medication with iron be dangerous?

Self-medication with iron is dangerous because, without a confirmed deficiency and monitoring of tests, iron can accumulate in the body, cause oxidative damage to the liver and other organs, mask the true cause of anemia or blood loss, and delay proper diagnosis and treatment.

How to really raise ferritin? What recommendations can you give to maintain normal ferritin levels over the long term?

Foremost, identify and eliminate the cause. In addition, it is important to balance the diet: consume enough protein and add red meat and liver.

Optimize absorption — do not combine iron with coffee, tea, or calcium.

And do not forget about prevention in risk groups: pregnant women, donors, women with heavy menstruation, vegans — take iron preparations prescribed by your doctor in courses. For example, during menstruation every month.

Healthy ferritin levels are your investment in stamina, beauty, and immunity. Be attentive to your body’s signals and don’t let iron deficiency steal your vital energy.