Ferritin

What is Ferritin?

A protein that stores iron; blood ferritin levels reflect the body's iron reserves.

Ferritin stores iron inside cells, and blood levels reflect how much iron the body has in reserve. Low ferritin points to iron deficiency; high levels can mean iron overload or reflect inflammation, since ferritin also rises as part of the body's acute-phase response to illness or injury. Normal ranges differ significantly between men and women, so results are usually interpreted against sex-specific reference values.

Tests often checked alongside this

• Serum Iron — shows circulating iron, not just stores
• TIBC/Transferrin Saturation — clarifies whether low ferritin reflects true deficiency
• Hemoglobin/CBC — distinguishes iron-deficiency anemia from early depletion without anemia

How this can show up in how you look and feel

• Low ferritin can be associated with hair thinning or increased shedding
• Some people notice persistent fatigue even without anemia
• Restless legs at night can be associated with lower iron stores
• Brittle nails are sometimes associated with long-standing low iron

What can affect this marker

• Diet and daily habits
• Medications and supplements
• Recent illness or inflammation
• Age, sex and genetics

What to track over time

• Your trend across repeat tests
• How lifestyle changes move it
• Alongside related biomarkers
• Symptoms like fatigue or hair loss

What to ask your doctor

• Is my level optimal, not just 'normal'?
• How often should I retest?
• Could anything be skewing this result?
• Do I need to change anything?

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