My ferritin is low — what should I do?
Low ferritin signals depleted iron stores and is the earliest reliable iron-deficiency marker. Confirm with iron, TIBC, transferrin saturation, and a CBC. Identify the source of loss; replete with oral or, when indicated, IV iron under provider review.
Full answer
Ferritin under the lower reference limit reliably signals depleted iron stores even before anemia develops. The workup includes serum iron, TIBC, transferrin saturation, reticulocyte count, and a CBC. In menstruating women, menstrual loss is the most common driver; in men and post-menopausal women, GI loss is presumed until proven otherwise and warrants GI workup. Repletion is oral every other day for absorption, or IV when oral fails, malabsorption is present, or repletion is urgent. Recheck at 8–12 weeks. Hormone optimization does not replace iron repletion.
Educational. Not a substitute for individualized provider review.
- Methodology — Primary source · oMeds
- Reviewed by Dr. Laura Purdy, MD, MBA · Clinical Director, oMeds · Last reviewed 2026-06-03