Evidence check: Eisen-Ferritin Selbsttest in the context of sleep

The link between iron/ferritin levels and sleep is scientifically established, particularly in restless legs syndrome (RLS) and sleep-related movement disorders. Iron deficiency can impair dopamine metabolism and reduce sleep quality. However, a direct-to-consumer (DTC) self-test for iron and ferritin in the context of sleep should be viewed with caution. Such tests typically measure only serum ferritin or iron, which does not capture the full iron homeostasis (e.g., storage iron, transferrin saturation). Moreover, ferritin levels fluctuate diurnally and can be falsely elevated by inflammation. Without clinical interpretation, sleep history, symptoms, and additional lab markers (e.g., CRP, transferrin), the utility for sleep optimization is questionable. The evidence for such self-tests is weak to unclear. A physician-led diagnostic workup remains the gold standard.