Key Benefits

• Check your body’s iron stores to spot deficiency or overload early.
• Spot early iron deficiency before anemia; ferritin drops first, enabling prompt action.
• Clarify fatigue, hair loss, brittle nails, or restless legs linked to low iron.
• Guide safe iron supplementation and dosing, or evaluation for bleeding or malabsorption.
• Protect fertility and menstrual health by detecting low stores from heavy periods.
• Support pregnancy by ensuring sufficient iron for fetal growth and maternal health.
• Flag potential iron overload from hemochromatosis, liver disease, or repeated transfusions.
• Best interpreted with CBC, iron studies, CRP, and your symptoms due to inflammation effects.

What is Ferritin?

Ferritin is the body’s main iron‑storage protein. It is a hollow, spherical protein cage (apoferritin) that packages iron safely inside cells. Most ferritin is made by liver cells and immune cells called macrophages, with large reserves in the liver, spleen, and bone marrow. A small amount enters the bloodstream from these tissues; this circulating ferritin (serum ferritin) is what blood tests detect.

Ferritin’s job is to keep iron available yet non‑toxic. By locking iron inside its core (ferric iron mineral), it prevents free iron from driving harmful oxidation, and it releases iron when tissues need it for hemoglobin, muscle oxygen storage, and energy enzymes (cytochromes). Because ferritin stores track the size of your iron reserves, the blood level generally mirrors whole‑body iron status. Ferritin also increases during inflammation or infection (acute‑phase response), as the body sequesters iron to limit microbial growth. In short, ferritin reflects how much iron you have on hand and helps the body balance iron safety with iron supply.

Why is Ferritin important?

Ferritin is the body’s iron‑storage protein; blood ferritin mirrors iron reserves and, to a degree, inflammation. Because iron drives hemoglobin, mitochondria, thyroid enzymes, and neurotransmitters, ferritin influences energy, cognition, exercise capacity, immunity, and pregnancy health.

Typical ranges are lower in women than men (about 20–150 vs 30–400) and fall in pregnancy; children vary by age. Without inflammation, healthy stores usually sit in the midrange rather than at extremes.

When ferritin is low, iron stores are depleted—often before hemoglobin drops. Cells make less ATP and thyroid activation falters, causing fatigue, reduced exercise tolerance, brain fog, headaches, hair shedding, brittle nails, cold intolerance, and restless legs. Heavy menstrual loss and pregnancy increase risk; in children and teens, low ferritin can impair attention, learning, growth, and mood.

High ferritin may reflect inflammation or liver injury (it is an acute‑phase protein), metabolic syndrome, infection, or malignancy—or true iron overload from transfusions or hereditary hemochromatosis. Excess iron catalyzes oxidative damage and deposits in liver, heart, joints, and pancreas, leading to fibrosis, arrhythmias, arthropathy, diabetes, and hypogonadism; men and postmenopausal women manifest overload earlier.

Viewed with hemoglobin, transferrin saturation, and inflammatory markers, ferritin flags both deficiency and toxic excess. Keeping stores in a steady midrange supports oxygen delivery, mitochondrial function, and neurocognition, and lowers long‑term risks of anemia, fatigue, cardiovascular strain, and organ damage.

What Insights Will I Get?

Ferritin measures the body’s iron reserves. It reflects how much iron is available to build hemoglobin for oxygen transport, to fuel mitochondria for energy production, and to support myoglobin in muscle, neurotransmitter synthesis in the brain, thyroid enzymes, and immune cell function. Because iron is both essential and potentially oxidative, the level of ferritin marks a balance between sufficiency and safety.

Low values usually reflect depleted iron stores, most often from ongoing blood loss, limited absorption, or increased needs. Physiology shifts toward conserving iron, reducing red blood cell production and mitochondrial activity, which can show up as fatigue, reduced aerobic capacity, brain fog, restless legs, and brittle hair or nails. Low ferritin is more common in menstruating individuals and during pregnancy, when iron demand rises for the placenta and fetus.

Being in range suggests iron stores are adequate to sustain stable oxygen delivery, muscular performance, cognitive work, thyroid-dependent metabolism, and immune defense without tipping into excess. For most people, an optimal set point sits away from the very low end and not near the top of the reference range.

High values usually reflect either true iron overload (e.g., hereditary hemochromatosis or transfusional iron) or a response to inflammation, infection, liver injury, or metabolic stress, since ferritin is an acute-phase protein. Sustained excess iron can drive oxidative stress and strain the liver, pancreas, heart, and endocrine metabolism.

Notes: Ferritin rises with acute illness, inflammation, and strenuous exercise and falls with recent blood loss. Pregnancy lowers typical values. Interpretation differs by sex and menopausal status. Lab methods vary; pairing with inflammatory markers and iron transport indices improves context.