Myths vs facts: Ferritin and fatigue

Ferritin is an iron-storage protein, but a single low ferritin level does not automatically explain fatigue. Myth: 'Low ferritin = iron deficiency = fatigue.' Fact: Ferritin can be falsely elevated during inflammation (e.g., infection, chronic disease) even when iron stores are low. Conversely, ferritin may be low without anemia, and fatigue has many causes (sleep, stress, thyroid, vitamin D deficiency). The MyBody-X ferritin test measures only ferritin, not the full iron panel (transferrin saturation, serum iron, hemoglobin). A SNP in the FUT2 gene (rs602662) affects vitamin B12 absorption, not ferritin directly. For a proper workup, medical blood counts and inflammatory markers (CRP) are required. Bottom line: Ferritin is one piece, not a standalone fatigue indicator.