Analysis of randomized trials concludes benefit for melatonin on sleep quality


Ferbuary 9, 2021

A review and meta-analysis of randomized controlled trials published on January 8, 2021 in the Journal of Neurology adds more evidence to melatonin’s ability to improve sleep.

Researchers at Tehran University of Medical Sciences selected 23 trials that investigated melatonin’s effects on the quality of sleep as assessed by the Pittsburgh Sleep Quality Index (PSQI) among 1,965 men and women with various diseases. The PSQI includes assessments of subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, sleep medication use and daytime dysfunction during the previous month.

Study sizes ranged from 16 to 711 participants, and follow-up periods varied from 2 to 24 weeks. Melatonin doses consisted of 2 to 10 milligrams per day. Pooling of the participants’ data found a significant difference in sleep quality between individuals who received melatonin and the control subjects, with those who received the hormone showing improvement. When participants were examined according to health status, melatonin had significant effects among those with respiratory diseases, metabolic disorders and sleep disorders. Both low and high doses of melatonin, respectively defined as 3 milligrams or less and over 3 milligrams, improved sleep quality.

Authors Gholami Fatemeh and colleagues remarked that melatonin has a known role in regulating circadian rhythms and sleep and may facilitate sleep by inhibiting the circadian stimulus for waking that comes from the brain’s suprachiasmatic nucleus. They noted that the decline in melatonin levels that occurs during aging may be responsible for the increased incidence of sleep disturbances observed among older individuals.

“To the best of our knowledge, this study is the first meta-analysis that investigated the effect of melatonin on sleep quality as measured by the PSQI in adults with various diseases,” they announced. “In conclusion, combined data from interventional studies revealed a significant improvement in sleep quality after melatonin intervention.”


Apply What You’ve Learned: Melatonin

  • Melatonin is a hormone released by the brain’s pineal gland in response to darkness. In addition to supporting quality sleep, melatonin has numerous other health benefits.
  • Melatonin helps inhibit oxidative stress, thereby supporting many areas of health.1
  • Going to bed in a completely dark room can enhance sleep by improving melatonin release. It is also recommended to avoid exposure to bright lights and digital devices within a few hours of bedtime.
  • Melatonin is available over the counter in a variety of doses and forms: capsules, liquid and tablets that dissolve in the mouth, regular and timed release, and as a stand-alone form or combined with other sleep-supportive ingredients.


  1. Ghorbaninejad P et al. Horm Mol Biol Clin Investig. 2020 Nov 11.

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