Melatonin in the Regulation of Sleep and Biological Rhythms

Melatonin, as a hormone of the circadian system, plays an important role in regulating physiological functions and facilitating adaptation to regular environmental changes. This review discusses the basics of circadian physiology directly related to the use of melatonin as hormone replacement therapy in older adults with decreased melatonin secretion and in the treatment of patients with chronic insomnia or circadian desynchronization. With stress on the importance of minimum effective doses, the use of both immediate- and sustained-release forms, the importance of regular dosing times, and the need to avoid bright light at times of elevated melatonin levels are discussed. Medical supervision is mandatory when using melatonin-containing drugs for the treatment of chronic insomnia.