Saffron and Sleep Quality: A Systematic Review of Randomized Controlled Trials

BACKGROUND: Sleep quality is defined as an individual’s consent to sleep experience. Poor sleep quality has important adverse health outcomes. There are drugs to treat sleep disorders but consumption of these drugs is accompanied by adverse effects whereas herbal treatments have fewer side effects. Saffron is spice obtained from Crocus sativus flower. Several articles have been done on its effects on the quality of sleep and its safety. This review for the first time critically evaluates effect of saffron on sleep quality improvement. METHOD: The search technique aims to get all related published data-based up to 2022 articles. PubMed, Central, Google Scholar, and Scopus were examined. Only full reports were evaluated (abstracts were excluded). The first screening was done by title and abstract. Then full text of articles was read and irrelevant articles were removed. Duplicate articles were also removed by Endnote. By using Cochrane risk of bias tool assessment, a quality score based on probability of bias was given. Methodological characteristics were also evaluated using the criteria of Stevinson and Ernst. RESULT: In the systematic review, 5 randomized clinical trials with 379 participants from 3 countries were identified. In placebo-comparison trials, saffron contains a large treatment. CONCLUSION: It seems that saffron has a beneficial influence on duration and quality of sleep. Saffron, crocin, and safranal induce hypnotic effects by increasing the duration of sleep. Research conducted so far provides initial support and safety for use of saffron to improve sleep quality.