Early in 1953, Nordlander (1953) first proposed that iron deficiency might be an important part of the pathophysiological process in RLS which was supported by consistent prevalence studies and recent pharmacological researches. Low serum iron levels (normal range: 50–170 μg/dL for men; 65–176 μg/dL for women; 50–120 μg/dL for children) presented in 25% of patients with severe RLS (Ekbom, 1960). While 43% of patients complaining of “leg restless” were found to be in the condition of iron deficiency (Matthews, 1976). The severity of the symptoms was found to be correlated with serum ferritin levels (normal range: 15–200 ng/mL for men; 12–150 ng/mL for women; 7–140 ng/mL for children) (O’Keeffe et al., 1994; Mizuno et al., 2005). Numbers of pharmacological studies of iron supplement for RLS gained therapeutic effects (Nordlander, 1953). CSF biological studies showed lower iron and ferritin levels in RLS patients, along with higher transferrin levels (Mizuno et al., 2005). However, a current study has suggested that in normal circumstances, the brain does not respond to peripheral variations in iron status (Ward et al., 2014). This might explain why some RLS patients had a normal or over-loaded serum iron level while their CSF iron level was decreased. Various medical imaging studies including ultrasound studies and MRI studies revealed a decreased iron levels in the substantia nigra and putamen, especially in the very severe patients (Schmidauer et al., 2005; Moon et al., 2014). Other studies demonstrated iron decrease in the red nucleus, thalamus and the pallidum (Haba-Rubio et al., 2005; Rizzo et al., 2013). However, MRI was not capable of locating the iron deficiency condition to particular cells up to now. Autopsy studies also reported a decrease in iron concentration in the substantia nigra (Moon et al., 2014).