https://www.selleckchem.com/products/apoptozole.html BACKGROUND Vitamin D exerts multiple pleiotropic effects beyond its role in calcium-phosphate metabolism. Growing evidence suggest an association between hypovitaminosis D and sleep disorders, thus increasing the interest on the role of this vitamin in the regulatory mechanisms of sleep-wake cycle. OBJECTIVE To explore and summarize the current knowledge about the role of vitamin D in sleep regulation and the impact of vitamin D deficiency on sleep disorders. METHODS The main regulatory mechanisms of vitamin D on sleep are explained. The literature was scanned to identify clinical trials and correlation studies showing an association between vitamin D deficiency and sleep disorders. RESULTS Vitamin D receptors and the enzymes that control its activation and degradation are expressed in several areas of the brain involved in sleep regulation. Vitamin D is also involved in the pathways of production of Melatonin, the hormone involved in the regulation of human circadian rhythms and sleep. Furthermore, vitamin D can affect sleep indirectly through non specific pain disorders, correlated with alterations in sleep quality, such as restless legs syndrome and obstructive sleep apnea syndrome. CONCLUSIONS Vitamin D has both a direct and an indirect role in the regulation of sleep. Although vitamin D deficiency has been associated to sleep disorders, there is still scant evidence to concretely support the role of vitamin D supplementation in the prevention or the treatment of sleep disturbances; indeed more intervention studies are needed to better clarify these aspects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.The encapsulation of bioactive compounds (BC) is an emerging technique for finding new medicines since it provides protection against degradation ambient factors before reaching the target site. Nanotechnology provides new methods for encapsulating BC and hence,