Ferritin is a protein that stores iron in your body. When your blood test comes back with a ferritin value, that number reflects how much iron your body has in reserve — not just what is circulating in your bloodstream right now. A ferritin of 25 ng/mL means something very different from 180 ng/mL, and understanding where you fall matters. Iron deficiency remains the most common nutritional deficiency worldwide, affecting roughly 2 billion people according to the World Health Organization. Yet most people glance at their ferritin result and have no idea whether to worry. This guide breaks down what ferritin measures, what the numbers mean across different ages and genders, what causes abnormal levels, and when you should act on your results.
What Is Ferritin?
Ferritin is a protein that stores iron inside your cells. Think of it as your body's iron savings account — while serum iron measures what's circulating in your blood right now, ferritin tells you how much iron your body has in reserve. Your liver, spleen, and bone marrow are the main storage sites.
The World Health Organization (WHO) recommends ferritin as the primary marker for assessing iron status. A single ferritin measurement reflects your total body iron stores more reliably than serum iron, which fluctuates throughout the day. Your hemoglobin can be perfectly normal while your ferritin is already dropping — meaning your reserves are depleting before you feel it.
About 1.6 billion people worldwide have iron-deficiency anemia (WHO, 2023), and low ferritin is the earliest warning sign before anemia develops.
Normal Ferritin Levels by Age and Gender
Reference ranges vary by lab, but these are the widely accepted values based on Mayo Clinic and clinical guidelines:
| Group | Normal Range |
|---|---|
| Adult men | 24–336 ng/mL |
| Adult women | 11–307 ng/mL |
| Newborns | 25–200 ng/mL |
| 1 month old | 200–600 ng/mL |
| 2–5 months | 50–200 ng/mL |
Key thresholds to know:
- < 15 ng/mL: Definite iron deficiency (WHO criteria)
- < 30 ng/mL: Iron stores depleted — anemia may not have developed yet
- 30–50 ng/mL: Some clinicians consider this "low-normal," especially in women with symptoms
- > 200 ng/mL (women) / > 300 ng/mL (men): Elevated ferritin — warrants investigation
A single number is less useful than a trend over time. A ferritin of 35 ng/mL means something different if it was 80 six months ago versus if it's been stable at 35 for two years. Among the 2,300+ blood test metrics processed through ViziAI, ferritin is one of the most commonly flagged values — and one where the trend direction matters as much as the number itself.
Low Ferritin: Causes and Symptoms
Low ferritin means your body's iron stores are running low. Iron deficiency is the most common nutritional deficiency worldwide — the WHO estimates it affects roughly 2 billion people. In women of reproductive age, iron deficiency prevalence reaches 30–40% in many populations.
Common Causes of Low Ferritin
Inadequate dietary iron is one of the most straightforward causes. People who eat little red meat, legumes, or dark leafy greens often fall short of the 18 mg daily requirement for women or 8 mg for men. Vegetarians and vegans are at particular risk because plant-based (non-heme) iron is absorbed at roughly one-third the rate of animal-based (heme) iron.
Blood loss is another major driver. Heavy menstrual periods are the leading cause of low ferritin in premenopausal women, but GI bleeding from ulcers or polyps and frequent blood donation also deplete stores steadily over time.
Malabsorption conditions such as celiac disease, inflammatory bowel disease, and gastric bypass surgery prevent the gut from absorbing iron efficiently, even when dietary intake appears sufficient. Finally, increased physiological demand during pregnancy pushes daily iron needs from 18 mg to 27 mg, and rapid growth in adolescents similarly strains reserves.
Symptoms of Low Ferritin
Fatigue is the most common complaint, but low ferritin affects the body in ways many people never connect to iron. The most widespread symptoms are persistent tiredness, low energy, and a general sense of weakness that doesn't improve with rest. A clinical trial found that 72% of women with ferritin below 30 ng/mL reported unexplained fatigue, and when ferritin was raised above 50 ng/mL with supplementation, fatigue scores improved significantly (Vaucher et al., 2012, CMAJ).
Beyond energy levels, low ferritin frequently causes dizziness, headaches, difficulty concentrating, and restless leg syndrome. These neurological symptoms occur because iron is essential for dopamine production and oxygen transport to the brain.
Visible signs are often the first clue that something is off. Hair loss and brittle nails are well-documented consequences of iron depletion, along with pale skin, cold hands and feet, and shortness of breath or heart palpitations during exertion.
High Ferritin: When to Be Concerned
High ferritin doesn't always mean you have too much iron. Ferritin is also an acute phase reactant — it rises in response to infection, inflammation, and tissue damage, regardless of iron status.
Common Causes of High Ferritin
Inflammation is the most frequent reason for elevated ferritin. Infections, autoimmune conditions like rheumatoid arthritis, and chronic diseases all trigger ferritin release as part of the body's acute phase response — meaning the number on your blood test may reflect inflammation rather than actual iron excess.
Liver disease is another common cause. Hepatitis, fatty liver disease (which affects an estimated 25% of the global population), and alcohol-related liver damage all cause ferritin to leak from damaged liver cells into the bloodstream. Hemochromatosis, a genetic iron-overload condition, affects roughly 1 in 200 people of Northern European descent and causes the body to absorb too much iron from food over decades.
Metabolic syndrome, including obesity and type 2 diabetes, can elevate ferritin independently of iron status. Repeated blood transfusions and certain blood disorders such as thalassemia also lead to iron accumulation and high ferritin readings.
If ferritin exceeds 1,000 ng/mL, further evaluation for liver disease, hemochromatosis, or malignancy is warranted. When transferrin saturation is above 45% alongside elevated ferritin, hemochromatosis becomes a strong possibility.
To distinguish true iron overload from inflammation, your doctor may also check CRP (C-reactive protein) and liver enzymes. Our system recognizes all of these related markers — ferritin, CRP, transferrin saturation, and liver enzymes — so when you upload a comprehensive blood panel, you can see how they move together over time.
When Should You Get a Ferritin Test?
The most common reason doctors order a ferritin test is unexplained fatigue or weakness that doesn't resolve with rest. If a complete blood count (CBC) shows low hemoglobin, ferritin is the logical next step to determine whether iron deficiency is the cause. The American Academy of Family Physicians (AAFP) recommends ferritin as the first-line test for evaluating anemia — combined with a CBC, it identifies iron-deficiency anemia with 95% accuracy (Guyatt et al., 1992).
Women with heavy menstrual bleeding should have ferritin checked regularly, as monthly blood loss can silently drain iron stores over months or years. During pregnancy, ferritin monitoring helps ensure the mother's reserves can support the increased demand. Patients managing chronic conditions such as kidney disease or inflammatory disorders also benefit from routine ferritin testing, since both the disease and its treatment can alter iron metabolism.
If you have a family history of hemochromatosis, genetic screening and periodic ferritin checks are recommended starting in early adulthood. Ferritin is not a one-time measurement — tracking it over time shows whether treatment is working, whether dietary changes are having an effect, or whether an underlying condition is worsening.
How to Track Your Ferritin Levels Over Time
A single blood test is a snapshot. When you see ferritin at 25 ng/mL, the first question should be: "What was it three months ago?" Is it falling, stable, or recovering with treatment? The difference between a stable ferritin of 30 ng/mL and one that has dropped from 80 to 30 over six months is clinically significant — the trend tells you whether your body is depleting reserves or holding steady.
ViziAI tracks 155 different biomarkers including ferritin, and users who upload 3+ reports typically see clear trend patterns emerge. By uploading your blood test PDFs to ViziAI, you can see your ferritin trend as a visual graph over time. Each new report updates the trend automatically, and the system recognizes ferritin under various lab naming conventions so nothing gets missed. Instead of telling your doctor "my ferritin is low," you can show them a concrete trend line: "my ferritin dropped from 45 to 18 over six months." That context changes the conversation from a single data point to an actionable pattern.
Frequently Asked Questions
Can low ferritin cause hair loss?
Yes, and it's one of the more under-recognized causes of hair shedding. Hair follicles are rapidly dividing cells that need adequate iron to grow properly. Dermatology research has shown that women with ferritin below 30 ng/mL have a significantly higher rate of hair loss (Park et al., 2013, Annals of Dermatology). Some specialists recommend a target ferritin of 50–70 ng/mL for optimal hair health. When ferritin is replenished through supplementation, hair shedding typically slows within 3–6 months — though regrowth takes longer. If you're losing hair and your ferritin is below 50, it's worth discussing iron supplementation with your doctor.
What's the difference between ferritin and iron in a blood test?
They measure different things. Serum iron reflects how much iron is circulating in your blood at that moment — it fluctuates throughout the day and is affected by recent meals. Ferritin reflects your stored iron reserves over time, making it far more stable and reliable. In early iron deficiency, serum iron may still appear normal while ferritin has already dropped — that's why the WHO identifies ferritin below 15 ng/mL as the definitive marker for iron deficiency. Your doctor may order both alongside transferrin saturation and TIBC (total iron-binding capacity) for a complete picture of your iron status.
What is the ideal ferritin level?
It depends on your clinical context. The standard reference range is 24–336 ng/mL for men and 11–307 ng/mL for women (Mayo Clinic). But "within range" doesn't always mean optimal. Some researchers suggest that people with fatigue or hair loss symptoms should aim for ferritin above 50 ng/mL before concluding that iron isn't the issue. For women planning pregnancy, a pre-conception ferritin above 40 ng/mL is recommended to meet the increased demands of pregnancy. Your doctor will interpret your result in the context of your symptoms, medical history, and other lab values.
Does high ferritin always mean too much iron?
No. Ferritin is an acute phase reactant, meaning it rises with inflammation, infection, or liver disease — even if your body's actual iron stores are normal or low. In fact, the most common cause of elevated ferritin is inflammation, not iron overload. To determine whether high ferritin reflects true iron excess, your doctor will check transferrin saturation. If it's above 45% along with elevated ferritin, hemochromatosis testing is indicated. Hemochromatosis, a genetic condition, affects about 1 in 200 people of Northern European ancestry. CRP levels help distinguish inflammatory ferritin elevation from iron-related causes.
Should I fast before a ferritin blood test?
Ferritin itself is not significantly affected by recent meals. However, most labs prefer a morning blood draw after 8–12 hours of fasting because ferritin is typically ordered alongside serum iron and other iron studies, which are meal-sensitive. Serum iron can rise by 30–50% after an iron-rich meal, skewing results. For consistency when comparing results over time, get tested under the same conditions — same time of day, same fasting state. A trend of multiple consistent measurements is always more informative than any single result.
This content is not medical advice. Consult your doctor about your test results.
Tracking your ferritin over time tells you more than any single number. Upload your first blood test PDF and let the trend build from there.