Glossary term

Ferritin

Your iron stores. Lab "normal" starts at 15 ng/mL; functional shortfall begins under 50 for most women.

Ferritin is the protein that stores iron. Standard lab normals bottom out at 15-30 ng/mL, but functional shortfall begins under 50 ng/mL in menstruating women and under 70 for endurance performance. Low ferritin without anemia is one of the most commonly missed drivers of fatigue, hair shedding, exercise intolerance, and restless legs - it can sit low for years before hemoglobin drops. If oral iron hasn't moved the number in 8-12 weeks, the fix is usually dose, form (ferrous bisglycinate beats ferrous sulfate for tolerance), or a hidden blood-loss workup. Included in the Advanced panel.

Unit

ng/mL

Typical range

Lab normal typically starts at 15-30 ng/mL; functional target for symptomatic women is often > 50-70 ng/mL.

Medically reviewed byDr. Lena Okafor, MD

Medical Director - updated April 2026 - How we review