What ferritin actually measures
Ferritin is a protein that stores iron inside your cells. The amount of ferritin in your blood is a reliable indicator of how much iron is in your body's savings account. When you're losing iron faster than you're absorbing it (heavy periods, pregnancy, low intake, malabsorption), your body draws down its ferritin reserves first — long before your hemoglobin (red blood cells) drops. This is why ferritin is the earliest, most sensitive marker of iron deficiency. A normal hemoglobin with low ferritin is called iron deficiency without anemia — and it absolutely causes symptoms.
The normal range vs. the optimal range
Most Canadian labs report ferritin as normal anywhere from 13 to 300 ng/mL. The problem: that range is statistical, not symptomatic. Many people feel terrible at the lower end. Here's what current research and clinical experience suggest: Below 15 ng/mL — Severe iron deficiency. Treatment essential. 15–30 ng/mL — Iron deficiency. Symptoms almost always present. 30–50 ng/mL — Sub-optimal. Most people still report fatigue, hair loss, or brain fog. 50–100 ng/mL — Adequate for most people. 100–200 ng/mL — Optimal. Best energy, hair growth, exercise tolerance. Above 300 ng/mL — Investigate for inflammation or iron overload. Many patients are told their ferritin of 22 is normal when, in fact, it's the cause of their fatigue. Don't let a single number on a lab report dismiss real symptoms.
Why women need higher ferritin than the lab normal
For women of reproductive age, the goal isn't just to be not anemic. It's to have enough iron stored to handle: • Monthly menstrual losses • Possible pregnancy • Daily wear-and-tear and exercise • Cellular oxygen delivery for the brain, hair, nails, and muscles Most clinicians who specialize in women's health now target a ferritin of at least 50 ng/mL, ideally 70–100 ng/mL for full symptom resolution. Hair loss in particular is strongly correlated with ferritin under 70 — even with completely normal hemoglobin.
What can falsely raise ferritin
Ferritin is also an acute phase reactant — meaning it rises during inflammation, even if iron stores are actually low. A ferritin of 80 in someone with autoimmune disease or active infection might actually represent depleted iron. If you suspect this, ask for: • CRP (C-reactive protein) — measures inflammation • Transferrin saturation (TSAT) — under 20% suggests true iron deficiency regardless of ferritin • Iron and TIBC Our physician at MED1 reviews the full panel — not just ferritin in isolation — to make an accurate diagnosis.
How fast can ferritin rise?
With oral iron pills: Ferritin typically rises 5–15 ng/mL per month, assuming good absorption. With IV iron infusion: A single Monoferric infusion (1000 mg) typically raises ferritin by 100–300 ng/mL within 4–6 weeks. Patients often go from 15 ng/mL to 150+ ng/mL in a single visit. This is why IV iron is transformative for people who've been stuck in the low ferritin, exhausted, but technically not anemic trap for years.