The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature

November 2014
Rebecca B Costello, Cynthia V Lentino, Courtney C Boyd, Meghan L O’Connell, Cindy C Crawford, Meredith L Sprengel, and Patricia A Deuster

Abstract

A systematic review was conducted using Samueli Institute’s Rapid Evidence Assessment of the Literature (REAL©) process to determine the evidence base for melatonin as an agent to optimize sleep or improve sleep quality, and generalize the results to a military, civilian, or other healthy, active, adult population. Multiple databases were searched yielding 35 randomized controlled trials (RCTs) meeting the review’s inclusion criteria, which were assessed for methodological quality as well as for melatonin effectiveness. The majority of included studies were high quality (83.0%).

Overall, according to Grading Recommendations, Assessment Development and Evaluation (GRADE) methodology, weak recommendations were made for preventing phase shifts from jet lag, for improving insomnia in both healthy volunteers and individuals with a history of insomnia, and for initiating sleep and/or improving sleep efficacy.

Based on the literature to date, no recommendations for use in shift workers or to improve hormonal phase shift changes in healthy people can be made at this time. Larger and longer-duration RCTs utilizing well characterized products are needed to warrant melatonin recommendations in young, healthy adults.

Conclusions

This review was conducted to critically assess the available peer-reviewed literature on the use of melatonin in military service members and in healthy subjects to determine whether melatonin might be useful in military populations. The review was limited by the inclusion of only two, though high quality, studies derived from military populations, which makes generalizations to the military less robust.

Additionally, the REAL process only included RCTs published in the English language which may have limited the depth of the review. Although the majority of the studies in this review were relatively high quality and limited to healthy adults, great heterogeneity existed in terms of sample sizes, assessment tools, and the range of melatonin dosages administered.

The use of melatonin by healthy adults shows promise to prevent phase shifts from jet lag and improvements in insomnia, but to a limited extent. For the initiation of sleep and sleep efficacy, the data cannot yet confirm a positive benefit. No recommendation can be proposed for the use of melatonin in shift workers.

Melatonin in a wide array of preparations and amounts demonstrates few significant and limiting adverse events. Because melatonin has a very low side effect profile and limited evidence of habituation and tolerance, its use in Service Members could be considered for specific tasks. However, additional randomized controlled trials with larger sample sizes, common assessment tools, and well-characterized interventions in physiologic dose ranges in military populations would be needed for confirmation.