Ferritin: How to Interpret Your Result as a Woman

What Ferritin Actually Measures

Ferritin is the primary iron-storage protein in your body. Your liver, spleen, and bone marrow pack iron into ferritin molecules to keep it safe, soluble, and ready for use. The small amount that leaks into your bloodstream gives clinicians a reliable window into your total iron reserve.

Serum ferritin is the most sensitive early marker of iron deficiency. Hemoglobin and hematocrit fall only after ferritin has already been depleted for weeks or months. That gap is clinically important for women because you can feel profoundly fatigued, notice your hair thinning, or struggle to concentrate while every other blood test still looks "normal."

How ferritin differs from serum iron and TIBC

Serum iron fluctuates hour to hour based on meals, stress, and the time of day. Transferrin saturation and total iron-binding capacity (TIBC) describe how much iron is in transit. Ferritin alone reflects the depot. For most women seeking to understand iron status, ferritin is the single most actionable number.

Why women need a sex-specific reference range

Standard laboratory reference ranges often include men, which skews the lower bound upward. A result of 18 ng/mL looks "normal" on a printout, yet research published in the American Journal of Clinical Nutrition showed that women with ferritin below 20 ng/mL had measurable reductions in work capacity independent of anemia. Reporting a number as "within range" without life-stage context is one of the most common reasons iron deficiency goes unaddressed in women.

Normal Ferritin Range for Women at Every Life Stage

There is no single universally agreed number. The range shifts with reproductive status, and functional thresholds differ from population reference intervals.

Reproductive years (menstruating women)

Most laboratories report a female adult reference range of 12-150 ng/mL. In practice, clinicians specializing in iron physiology use a functional floor of 30 ng/mL. Below that, cellular iron delivery to rapidly dividing cells, hair follicles, and the central nervous system may be compromised even when hemoglobin remains normal.

If you menstruate heavily, your ferritin may trend toward the lower end of the reference range throughout your reproductive years. A study in the American Journal of Obstetrics and Gynecology found that approximately 33 percent of otherwise healthy premenopausal women had ferritin below 15 ng/mL.

Trying to conceive and early pregnancy

Entering pregnancy with ferritin below 30 ng/mL significantly raises the risk of iron-deficiency anemia in the second and third trimesters. ACOG Practice Bulletin 233 recommends screening all pregnant women for anemia at the first prenatal visit and supplementing when ferritin is below 30 ng/mL, regardless of hemoglobin.

Plasma volume expands by roughly 40-50 percent during pregnancy, which dilutes ferritin and can mask iron depletion. A ferritin of 20 ng/mL at 28 weeks represents a far more serious deficit than the same number in a non-pregnant woman.

Postpartum and lactation

Blood loss at delivery typically removes 200-500 mL, dropping ferritin sharply. Studies show that up to 50 percent of postpartum women are iron-deficient at six weeks after delivery. Breastfeeding itself does not meaningfully deplete maternal iron, but the combined demand of recovery plus lactation means ferritin frequently remains low for months. Oral iron supplements are safe during breastfeeding; iron transfer into breast milk is tightly regulated by the infant's gut.

Perimenopause

As cycles become irregular and blood loss decreases, ferritin often rises. A woman who had a ferritin of 14 ng/mL at age 40 may have a ferritin of 60 ng/mL by age 48 without any change in diet. This can give a false impression of adequate stores. Conversely, women who experience heavier flooding during perimenopause may have ferritin drop precipitously before cycles finally stop.

Fatigue during perimenopause is common and multifactorial. Checking ferritin alongside estradiol, TSH, and a complete blood count gives a more complete picture.

Post-menopause

After menstrual blood loss ends, ferritin tends to stabilize and often rises into the mid-to-upper portion of the reference range. Unexplained ferritin above 200 ng/mL in a post-menopausal woman warrants evaluation for hemochromatosis, liver disease, or inflammatory conditions rather than assumed iron sufficiency.

What Low Ferritin Means

Low ferritin means your iron stores are depleted. Symptoms can appear before anemia develops, a stage called iron deficiency without anemia or "pre-latent to latent" iron deficiency.

Symptoms women notice first

• Fatigue that does not improve with rest
• Hair shedding, particularly diffuse telogen effluvium
• Brittle nails with longitudinal ridging
• Cold intolerance
• Brain fog and difficulty concentrating
• Restless legs syndrome, especially at night
• Reduced exercise tolerance or breathlessness on exertion

A 2023 analysis in the Journal of the American Medical Association confirmed that iron deficiency without anemia is undertreated in women, and that symptomatic benefit from repletion can occur with ferritin rises as modest as 15-20 ng/mL.

Common causes in women

Heavy menstrual bleeding (HMB) is the leading cause of iron deficiency worldwide in women of reproductive age. Losing more than 80 mL per cycle creates a net monthly iron deficit that diet alone rarely compensates.

PCOS creates a dual risk. Irregular or anovulatory cycles can reduce monthly blood loss, but the chronic low-grade inflammation associated with insulin resistance may suppress ferroportin, the channel that releases iron from stores, leading to functional iron deficiency even when ferritin appears borderline.

Pregnancy and postpartum period as described above.

Celiac disease and gut absorption issues. Iron absorption occurs primarily in the duodenum. Untreated celiac disease and inflammatory bowel disease both impair absorption independent of dietary intake. If your ferritin remains low despite oral supplementation, checking tissue transglutaminase IgA is reasonable.

Vegetarian and vegan diets. Non-heme iron from plant foods has an absorption rate of roughly 2-20 percent compared to 15-35 percent for heme iron. The Academy of Nutrition and Dietetics recommends that iron intake for vegetarians be approximately 1.8 times the standard RDA to compensate.

Thyroid disease. Hypothyroidism slows gastric motility and may reduce iron absorption. Postpartum thyroiditis, which affects roughly 5-10 percent of women after delivery, can further complicate iron recovery.

Ferritin thresholds linked to specific conditions

| Condition | Ferritin threshold that predicts effect | |---|---| | Telogen effluvium (diffuse hair shedding) | <40 ng/mL | | Restless legs syndrome | <75 ng/mL | | Symptomatic iron deficiency without anemia | <30 ng/mL | | Iron-deficiency anemia (WHO definition) | <12 ng/mL + Hgb <12 g/dL |

These thresholds come from dedicated research rather than general reference ranges and are more clinically meaningful for most women.

What High Ferritin Means

Elevated ferritin is not the same as iron overload, and this distinction matters.

Ferritin as an acute-phase reactant

Ferritin rises in response to inflammation, infection, liver injury, and certain malignancies because it is an acute-phase protein. This means a woman with rheumatoid arthritis, endometriosis-related systemic inflammation, chronic kidney disease, or even a recent upper respiratory infection may have a ferritin of 180-300 ng/mL with perfectly normal or even depleted functional iron. In these cases, transferrin saturation will be low or normal, distinguishing inflammatory elevation from true iron excess.

Causes of genuinely elevated iron stores

Hereditary hemochromatosis (HFE gene mutations) is the most common genetic metabolic disorder in people of Northern European descent. Women are partially protected by menstrual blood loss, so symptoms often emerge 10-20 years later than in men, frequently after menopause. Classic presentation includes ferritin above 300-400 ng/mL combined with transferrin saturation above 45 percent. The American Association for the Study of Liver Diseases recommends HFE gene testing when transferrin saturation exceeds 45 percent on two fasting samples.

Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD). Ferritin is often modestly elevated (100-300 ng/mL) in women with MASLD and may correlate with hepatic fibrosis severity, particularly in those with PCOS or insulin resistance.

Alcohol. Even moderate to heavy alcohol use raises ferritin through hepatic inflammation.

Recent illness or vaccination. Ferritin can double within 24-72 hours of a significant inflammatory stimulus and returns to baseline within two to four weeks.

When to escalate workup for high ferritin

If ferritin exceeds 200 ng/mL in a non-pregnant woman and you have no obvious inflammatory cause, your clinician should order at minimum:

• Fasting transferrin saturation
• Liver function tests (AST, ALT, GGT)
• CRP or ESR to quantify inflammatory burden
• HFE gene mutation panel if transferrin saturation is above 45 percent

The WomanRx editorial team uses the following decision framework for high ferritin interpretation in women:

Step 1. Is there an acute inflammatory cause (infection, recent surgery, active autoimmune flare)? Retest in four to six weeks after resolution.

Step 2. Is transferrin saturation above 45 percent on a fasting sample? Proceed to HFE testing.

Step 3. Is transferrin saturation normal or low with elevated ferritin? Evaluate for MASLD, alcohol use, and chronic inflammatory conditions including endometriosis and PCOS.

Step 4. Is ferritin above 500 ng/mL without clear cause? Hematology referral for evaluation of rare causes including adult-onset Still disease, hemophagocytic lymphohistiocytosis, and myelodysplastic syndromes.

How to Raise Low Ferritin

Repletion strategy depends on how depleted you are and why. Diet is rarely sufficient when ferritin is below 20 ng/mL; supplementation is almost always needed.

Oral iron supplementation

Ferrous sulfate 325 mg (containing 65 mg elemental iron) every other day is now the preferred schedule based on a 2017 study in The Lancet Haematology showing that alternate-day dosing produces higher fractional absorption than daily dosing by allowing hepcidin levels to reset between doses.

Side effects including constipation, nausea, and dark stools are the main reasons women stop taking iron. Lower-dose formulations such as ferrous bisglycinate 25-36 mg elemental iron have significantly better gastrointestinal tolerability, though head-to-head repletion speed data in women specifically are limited.

Vitamin C (250-500 mg) taken simultaneously enhances non-heme iron absorption by keeping iron in its reduced ferrous state. Coffee, tea, calcium supplements, and antacids taken within two hours of iron will substantially reduce absorption.

Expect ferritin to rise by approximately 2-5 ng/mL per week with consistent oral supplementation. A starting ferritin of 12 ng/mL may take three to six months to reach 50 ng/mL.

Intravenous iron

IV iron is appropriate when oral iron fails, causes intolerable side effects, or when ferritin needs to be repleted quickly, such as in the third trimester of pregnancy or severe postpartum hemorrhage. Formulations licensed in the United States include ferric carboxymaltose (Injectafer), low-molecular-weight iron dextran, and ferumoxytol (Feraheme).

ACOG Committee Opinion 1030 supports IV iron for postpartum anemia when hemoglobin is below 8 g/dL or when oral iron is not tolerated. Ferritin can rise 50-100 ng/mL within two weeks of a single IV dose.

Dietary sources of iron

| Food | Iron per serving | Notes | |---|---|---| | Beef liver (3 oz) | 5 mg heme | Highest bioavailability; avoid in high amounts in pregnancy due to vitamin A | | Clams (3 oz) | 23 mg heme | Exceptional source | | Beef (3 oz, lean) | 2.5 mg heme | Well absorbed | | Lentils (1 cup cooked) | 6.6 mg non-heme | Pair with vitamin C | | Tofu, firm (3 oz) | 3 mg non-heme | Pair with vitamin C | | Pumpkin seeds (1 oz) | 2.5 mg non-heme | Convenient snack |

Heme iron from animal sources is absorbed at roughly four times the rate of non-heme iron regardless of body iron status.

Addressing the underlying cause

Repletion without addressing the cause is a temporary fix. Heavy menstrual bleeding should be evaluated and treated. Hormonal IUDs (levonorgestrel-releasing intrauterine systems) reduce menstrual blood loss by 70-90 percent and are endorsed by ACOG as first-line medical management for HMB. Combined oral contraceptives reduce cycle blood loss by roughly 40-50 percent and are a reasonable alternative for women who prefer a daily pill.

How to Lower High Ferritin

The right approach depends entirely on the cause.

If inflammation is driving the elevation

Treat the underlying condition. A woman with active endometriosis and ferritin of 180 ng/mL does not need iron restriction; she needs endometriosis management. Ferritin should be rechecked after the inflammatory process is controlled.

If hereditary hemochromatosis is confirmed

Therapeutic phlebotomy (removing 450-500 mL of blood weekly or biweekly) is the definitive treatment. Each unit of blood removed reduces ferritin by approximately 30-50 ng/mL. Treatment continues until ferritin reaches 50-100 ng/mL, then maintenance phlebotomy keeps it there. Women with hemochromatosis who are still menstruating often accumulate iron more slowly and may not need phlebotomy until after menopause.

Dietary and lifestyle modifications for mildly elevated ferritin

When ferritin is modestly elevated (150-250 ng/mL) in the setting of MASLD or metabolic syndrome without confirmed hemochromatosis:

• Reduce red meat to two to three servings per week
• Avoid cooking in cast iron pans
• Limit vitamin C supplements with iron-rich meals (though avoid restricting whole fruits)
• Eliminate or sharply reduce alcohol
• Address insulin resistance through diet, exercise, and medication if indicated. Metformin does not directly lower ferritin, but improving insulin sensitivity reduces hepatic inflammation and ferritin over three to six months.

Ferritin and Pregnancy and Lactation

Pregnancy changes ferritin interpretation substantially, so this topic deserves direct attention.

Why ferritin drops in pregnancy

Plasma volume expansion dilutes all serum proteins, including ferritin. A pre-pregnancy ferritin of 45 ng/mL can fall to 20 ng/mL by the second trimester without any change in actual iron stores, and it will fall further if the growing fetus and placenta draw on reserves.

The fetus preferentially extracts iron across the placenta even when maternal stores are depleted, meaning maternal iron deficiency is the first casualty. Severe maternal iron deficiency (ferritin <12 ng/mL combined with hemoglobin <10 g/dL) is associated with preterm birth, low birth weight, and impaired fetal neurodevelopment, based on data from a Cochrane systematic review.

Supplementation in pregnancy

WHO guidelines recommend 30-60 mg elemental iron daily throughout pregnancy for all women. Women entering pregnancy with ferritin below 30 ng/mL or confirmed iron deficiency anemia may need 100-200 mg elemental iron daily in divided doses. IV iron is safe in the second and third trimesters and is preferred over oral iron when hemoglobin is below 9 g/dL or when oral tolerance is poor.

Ferritin during breastfeeding

Iron supplementation for iron-deficient breastfeeding women is safe and does not alter breast milk composition meaningfully, because mammary epithelial cells tightly regulate iron secretion into milk based on the infant's lactoferrin-mediated signaling. If you are postpartum and iron deficient, supplementing will restore your energy and hair growth without disadvantaging your infant.

No contraception requirement

Ferritin is a lab test, not a teratogen. No contraception requirement applies. If you are taking oral iron supplements, they carry no pregnancy risk and are in fact recommended during pregnancy.

Who Should Have Ferritin Checked

Ferritin screening is not part of standard adult preventive care in all guidelines, but certain women have a clear indication:

Test ferritin if you:

• Menstruate heavily (soaking a pad or tampon more than every hour for two or more hours)
• Have unexplained fatigue unresponsive to sleep improvement
• Notice diffuse hair shedding lasting more than three months
• Are planning pregnancy or are currently pregnant
• Have PCOS, endometriosis, or inflammatory bowel disease
• Have restless legs syndrome
• Have hypothyroidism (absorption may be compromised)
• Follow a vegetarian or vegan diet
• Are postpartum within the first six months

Ferritin is less informative when:

• You have had a major illness, surgery, or infection in the past four weeks
• You have active autoimmune disease in a flare (the result will reflect inflammation, not stores)

In these situations, a complete iron panel including serum iron, TIBC, and transferrin saturation alongside ferritin gives a more reliable picture.

The Evidence Gap in Women

Women have been consistently underrepresented in iron metabolism trials. Most foundational data on ferritin thresholds, repletion speed, and symptom resolution come from studies conducted predominantly in men or in pregnant women, which leaves a gap for non-pregnant reproductive-age women and perimenopausal women specifically.

The functional thresholds used in clinical practice (ferritin <30 for iron deficiency, <40 for hair loss, <75 for restless legs) are derived from smaller observational studies and expert consensus rather than large randomized trials in women. What is directly studied: ferritin in pregnancy. What is extrapolated from smaller or mixed-sex cohorts: optimal repletion targets for hair loss, neurological symptoms, and exercise performance.

This honesty matters because it means your symptoms are the most important data point alongside the number. A ferritin of 22 ng/mL with significant fatigue and hair shedding warrants a therapeutic trial of iron repletion even when the lab report reads "normal."

As The Menopause Society's 2023 position statement notes regarding nutrient deficiencies in midlife women, clinical decision-making should integrate symptom burden with laboratory values rather than relying on reference ranges designed for a broader population.