What role does Ferritin play in sleep?

Ferritin is the primary iron storage protein in the body. Low ferritin levels indicate iron deficiency, which can impair sleep through several mechanisms. The most established link is with Restless Legs Syndrome (RLS), a sensorimotor disorder characterized by an urge to move the legs and unpleasant sensations during rest, severely disrupting sleep. Epidemiological studies show that low serum ferritin (<50–75 µg/l) is associated with increased RLS risk. Pathophysiologically, iron deficiency is thought to impair brain dopamine synthesis because iron is an essential cofactor for tyrosine hydroxylase, the rate-limiting enzyme in dopamine production. Disruptions in the dopaminergic system are closely tied to RLS and sleep disturbances. Additionally, iron deficiency may alter sleep architecture independently of RLS, e.g., by increasing nocturnal awakenings or reducing slow-wave sleep. However, the evidence is largely mechanistic and derived from observational studies; randomized controlled trials of ferritin supplementation for sleep problems show mixed results. Importantly, ferritin is an acute-phase protein that can be elevated during inflammation – a normal or high ferritin level does not reliably rule out functional iron deficiency. Therefore, ferritin measurement in the context of sleep disorders should always be interpreted together with other iron parameters (transferrin saturation, soluble transferrin receptor). The provided context contains no specific information on ferritin and sleep; this answer is based on general medical knowledge.