What do the numbers mean?
| Ferritin level | Standard label | How you may feel |
|---|---|---|
| Below 12 µg/L | Deficient | Severe fatigue, hair loss, shortness of breath |
| 12–30 µg/L | Low normal | Persistent fatigue, brain fog, poor exercise recovery |
| 30–100 µg/L | Normal | Some still feel symptoms below 50 |
| 100–200 µg/L | Optimal | Good energy, healthy hair, strong immune function |
Ferritin is your body's iron storage protein. A low reading means your cells are running on near-empty reserves — even if you're not technically anaemic yet.
Normal vs Optimal — there is a difference
Most labs flag ferritin as "normal" if it's above 12–15 µg/L. But research — and many functional medicine doctors — suggest you need ferritin above 50–70 µg/L to feel genuinely well.
A result of 18 µg/L will pass through an NHS or private lab as normal. Yet patients at that level frequently report debilitating fatigue, hair thinning, and impaired concentration. This gap between "not deficient" and "actually optimal" is one of the most common reasons people feel dismissed.
Common symptoms you might notice
Common causes
- Insufficient dietary iron (especially in vegetarians and vegans)
- Heavy menstrual periods — the single most common cause in women
- Poor iron absorption (coeliac disease, gut inflammation)
- Pregnancy — increased demand depletes stores rapidly
- Chronic bleeding (GI tract, fibroids)
- Intense endurance training (runner's foot-strike haemolysis)
Questions to ask your doctor
Copy these before your next appointment. Your doctor will appreciate that you came prepared.
- My ferritin is {value} — is that optimal, or just not deficient?
- Should we treat symptoms, or wait until I reach a clinical threshold?
- Would an iron infusion be appropriate, or should we trial oral supplementation first?
- Are there absorption issues we should rule out — coeliac disease, for example?
- How long before I should expect to feel better once treatment starts?
Have this marker in your results?
See exactly where your ferritin sits against optimal ranges, not just lab reference ranges. Upload your full report and get a plain-English breakdown of every value — plus a personalised question list for your doctor.