Melatonin and human sleep

Abstract

The major hormone of the circadian system, melatonin, plays an important role in human sleep regulation, acting via both circadian and homeostatic mechanisms. Melatonin treatment can be used to treat chronic insomnias of different origin and circadian sleep disorders. However, if administered in high doses or at inappropriate times, melatonin might induce the circadian rhythm disorders or sleep abnormalities, rather than cure them.