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Poor sleep quality can lead to a greater risk of mental health problems, obesity, diabetes, and hypertension.[1] Given these repercussions, identifying effective strategies that improve sleep quality is critical. What supplements does the recent evidence show to be effective in improving sleep quality?

The study

This systematic review and meta-analysis of 31 randomized controlled trials (with 2,573 total participants) evaluated recent research to identify the types of supplements that are effective at improving subjective measures of sleep quality, as measured by the Pittsburgh Sleep Quality Index (PSQI) questionnaire (higher scores indicate worse sleep quality). The meta-analysis included 15 studies, and the remaining 16 studies were presented narratively.

The results

The meta-analysis showed that melatonin, amino acids, and vitamin D reduced PSQI scores, with a high degree of heterogeneity for melatonin and vitamin D. The narrative review found mixed results for magnesium, melatonin, nitrates, and resveratrol. No improvements in sleep quality were found for omega-3 supplementation, but one study found zinc to be efficacious. One small study showed that the combination of melatonin, zinc, and magnesium decreased PSQI.


The inclusion of only randomized controlled trials is a strength of this study. However, most studies had a small sample size and broad ranges in supplementation dose and duration.

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This Study Summary was published on March 5 2021.