Search Evidence
Glycine reduces sleep latency in human RCTs
Glycine (3g before bed) significantly reduces sleep onset latency and improves subjective sleep quality in healthy adults. Evidence from 3 human RCTs shows consistent effects, with the mechanism involving NMDA receptor modulation and thermoregulation.
Magnesium supplementation improves sleep quality, especially in deficient or elderly populations
Magnesium supplementation (500mg) for 8 weeks significantly improves sleep efficiency, total sleep time, and PSQI scores in elderly adults with primary insomnia. Effects are most pronounced in individuals with magnesium deficiency.
Melatonin reduces sleep onset latency by approximately 7 minutes in adults with primary sleep disorders
A comprehensive meta-analysis of 19 RCTs (1,683 participants) found melatonin reduces sleep latency by ~7 minutes and increases total sleep time by ~8 minutes. Effects are more pronounced in older adults and those with circadian rhythm disruptions.
Tart cherry juice improves sleep duration and efficiency in older adults with insomnia
Tart cherry juice (240ml twice daily) increases total sleep time by approximately 84 minutes and improves sleep efficiency in older adults with insomnia. The effect is attributed to natural melatonin content and procyanidins.
L-theanine improves subjective sleep quality and reduces anxiety without causing drowsiness
L-theanine (200mg daily) improves subjective sleep quality and reduces anxiety in adults with high anxiety levels. Unlike many sleep aids, it does not cause daytime drowsiness and promotes relaxation via alpha-wave enhancement.
Ashwagandha root extract (300mg BID) significantly improves sleep quality and reduces sleep onset latency in adults with insomnia
A well-designed 8-week RCT (n=138) found ashwagandha root extract significantly improved PSQI scores, reduced sleep onset latency, and improved sleep efficiency. Benefits were most pronounced in adults with insomnia and anxiety.
Apigenin, a flavonoid in chamomile, may promote sleep onset via benzodiazepine receptor binding
Apigenin binds to benzodiazepine receptors and enhances GABAergic activity, promoting sedation. While preclinical evidence is strong, human clinical trials are limited. Chamomile, a natural source, has shown modest sleep benefits.
Glycine improves overall sleep quality and reduces daytime sleepiness
Beyond reducing sleep latency, glycine (3g before bed) improves PSG-measured sleep quality including increased REM sleep and reduced nocturnal awakenings. Daytime sleepiness and fatigue are also significantly reduced the following morning.
Magnesium supplementation increases slow-wave (deep) sleep and improves sleep architecture
Magnesium supplementation (500mg for 8 weeks) significantly increases slow-wave sleep duration and improves overall sleep architecture in elderly adults with insomnia. The effect is linked to NMDA antagonism and GABA potentiation, which promote deeper, more restorative sleep.
Low-dose melatonin (0.5mg) effectively shifts circadian rhythm for jet lag, shift work, and delayed sleep phase syndrome
Melatonin is the most potent chronobiotic available. Administered 5 hours before dim-light melatonin onset (DLMO), even low doses (0.5mg) produce a 1-2 hour phase advance. This makes it effective for jet lag, shift work adaptation, and delayed sleep phase syndrome. Timing is more critical than dose.
Moderate-intensity aerobic exercise (150 min/week) significantly improves sleep quality in adults with chronic insomnia
A 4-week RCT found 150 min/week of moderate aerobic exercise significantly improved PSQI scores and objective sleep measures in adults with chronic insomnia. Exercise is recommended as a first-line behavioral intervention for insomnia.