Effect of Melatonin on the Sleep Quality: A Systematic Review

Introduction:Sleep is one of the most important human needs affected by many factors. Sleep disorders, such as insomnia and delayed sleep, are very common and can affect the quality and quantity of sleep. The current systematic review aimed to evaluate the evidence on the effectiveness of melatonin treatment on sleep quality. Methods:The data on the effect of melatonin on sleep were collected using seven English databases, including Scopus, PubMed, Ovid, ProQuest, and Science Direct, as well as six Persian databases, including Iran Medex, SID, IRANDOC, Magiran, MEDLIB, and Noormags, from their inception up to the end of January 2020. English language, randomized clinical trials, human samples, and age of higher than 18 years were the main eligibility criteria. Nonrandomized clinical trials or those without a control group were excluded from the present study. Results: Seven articles met the eligibility criteria for being included in this review. In the aforementioned studies, the effect of melatonin therapy on sleep quality was assessed in 343 subjects. The majority (86%) of the studies confirmed the effectiveness of melatonin treatment on sleep quality. Conclusion: Melatonin as an orally administered drug had beneficial effects on sleep quality. These effects of melatonin attributed to more efficient healthier sleep, deeper sleep, longer sleep duration without causing fatigue and early morning drowsiness, and faster sleeping. One of the limitations of the present study was considered reviewing articles without the consideration of the medical conditions of the subjects. Moreover, the type of sleep disorder was not investigated in this review.