The short answer
Ferritin shows how much iron you have stored. Many labs call anything from about 10 to 120 µg/L normal for women, but a result near the bottom of that range often means your stores are close to empty. The Iron Guide aims for 50 to 80 µg/L.
Ferritin is the protein that stores iron, mostly in your liver. A little of it leaks into your blood, roughly in proportion to what is stored, so a ferritin test reads your savings rather than today's traffic. It is the best single number for iron stores, with one catch: it rises with inflammation.
What the numbers usually mean
| Ferritin | What it usually means |
|---|---|
| Under 15 µg/L | Stores are empty and iron deficiency is very likely. See your doctor. |
| 15–30 µg/L | Stores are depleted. Many women already feel it. |
| 30–50 µg/L | Not deficient, not yet full. |
| 50–80 µg/L | The guide's goal: enough to ride out a few heavy months. |
| Above your lab's range | Often inflammation, sometimes too much iron. A question for your doctor. |
Why normal is not optimal
A lab range describes most of the people the lab tested, and many of them are low on iron too. Being inside it means nothing alarming was found. It does not mean your stores are full. Haemoglobin, the number most checkups look at, is the last to fall: you can run low on iron for months while it still looks fine.
- µg/L10Where many lab ranges for women start
- µg/L30Below this, stores count as depleted
- µg/L50–80The goal this guide aims for
One number, different feelings
The same ferritin feels different in different people. Some women feel unwell at 30 µg/L and others feel fine at 15. Track how you feel next to your numbers, and judge your progress by both.
These goals are stricter than your lab's range. They are targets to discuss with your doctor, not a diagnosis. A ferritin under 15 µg/L, a haemoglobin below your lab's range, or a ferritin above it are reasons to see your doctor soon.
A real page from The Iron GuideEvery marker on one card, with a lab range and a goal.See more pagesQuestions
Are µg/L and ng/mL the same for ferritin?
Yes. 1 µg/L is 1 ng/mL, so the number does not change. The unit converter handles the other markers.
Is a high ferritin a good sign?
Not by itself. Ferritin also rises with inflammation, infection, liver problems and too much iron. A ferritin above your lab's range is a question for your doctor.
Does my period change my ferritin?
Ferritin moves over months, so one period barely shifts it. The guide still suggests testing outside your period and once you have been well for 3 to 4 days, so the rest of the panel is clean too.
Sources
- 1.World Health Organization. Guideline on use of ferritin concentrations to assess iron status in individuals and populations, 2020
- 2.NIH Office of Dietary Supplements. Iron: fact sheet for health professionals
- 3.The Iron Guide, part 3: Your numbers
This page has not been reviewed by a clinician yet. Read it as general education, and take your own results to your doctor.
Educational, not medical advice. ferritin.ai does not diagnose or treat any condition, and it never sets a dose. Talk to your doctor about your own results.