Approximately 30% of adults experience insomnia symptoms. The supplement industry offers dozens of natural sleep aids - but the evidence behind them varies enormously. This guide ranks them by evidence strength and explains the one intervention that outperforms all of them.
For educational purposes only — not medical advice. How we evaluate evidence →
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Coeheal Editorial Team
Coeheal Editorial Team
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Coeheal Editorial Team
Editorially reviewed for accuracy against cited sources. This is an editorial review, not a medical or clinical review. For personalised health advice, consult a qualified healthcare professional.
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This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making health decisions. Our editorial standards →
Sleep onset insomnia (difficulty falling asleep): often driven by anxiety, racing thoughts, elevated cortisol in the evening, or circadian rhythm misalignment. Sleep maintenance insomnia (waking during the night): often driven by blood sugar dysregulation, sleep apnoea, pain, or alcohol consumption. Early morning awakening: often associated with depression or anxiety. Non-restorative sleep: often associated with sleep apnoea, poor sleep architecture, or chronic stress. Supplements work best when the underlying cause is addressed. A person with undiagnosed sleep apnoea will not benefit from melatonin. The most important question before taking any sleep supplement is: what is actually disrupting my sleep?
Melatonin: most effective for circadian rhythm disorders (jet lag, shift work, delayed sleep phase syndrome) and sleep onset in older adults. Critical dosing: the commonly sold doses (5-10 mg) are 5-20 times higher than the physiological dose needed. A 2014 meta-analysis found 0.5 mg was as effective as 5 mg for improving sleep onset with less next-day grogginess. Start with 0.3-0.5 mg, 30-60 minutes before bed; increase to 1-3 mg if needed. Magnesium glycinate: 300-400 mg, 1-2 hours before bed; a 2012 RCT significantly improved sleep quality, sleep time, and sleep efficiency; particularly effective for people with magnesium deficiency. CBT-I (Cognitive Behavioural Therapy for Insomnia): not a supplement but the most effective treatment for chronic insomnia; a 2015 meta-analysis found CBT-I produced larger and more durable improvements than any pharmacological or supplement intervention; available through therapists, online programmes (Sleepio, Somryst), and self-help books.
L-theanine: an amino acid found in green tea; promotes relaxation without sedation by increasing alpha brain wave activity and GABA levels; a 2019 RCT found 200 mg improved sleep quality, sleep efficiency, and morning alertness; 200-400 mg, 30-60 minutes before bed. Glycine: lowers core body temperature and modulates NMDA receptors; a 2012 RCT found 3 g before bed improved subjective sleep quality and reduced daytime sleepiness; 3 g, 30-60 minutes before bed; available as an inexpensive powder. Ashwagandha (KSM-66 or Sensoril): a 2019 RCT found 300 mg twice daily significantly improved sleep quality, sleep onset latency, and morning alertness; most effective for stress-related sleep disruption. Tart cherry juice: naturally high in melatonin and tryptophan; a 2012 RCT found 30 ml concentrate twice daily increased sleep time by 39 minutes and reduced insomnia severity.
Valerian root: a 2006 systematic review of 16 RCTs found valerian may improve sleep quality but evidence was not conclusive; 300-600 mg standardised extract (0.8% valerenic acid), 30-60 minutes before bed; generally safe for short-term use (up to 4-6 weeks). Passionflower: a 2011 RCT found passionflower tea improved subjective sleep quality; limited clinical evidence; may work synergistically with valerian. Lemon balm: mild anxiolytic and sleep-promoting effects; often combined with valerian; 300-600 mg before bed. Lavender (oral, as Silexan): a 2014 meta-analysis found oral lavender oil (80 mg/day) significantly improved sleep quality and reduced anxiety. CBD: most studies are small and short-term; a 2019 case series found CBD improved sleep in 66% of patients with anxiety and sleep complaints; 25-75 mg before bed; quality varies enormously - look for third-party tested, full-spectrum or broad-spectrum CBD.
Light management: get bright light within 30 minutes of waking; avoid bright light and blue light for 1-2 hours before bed; keep the bedroom completely dark. Temperature: bedroom should be 18-19 degrees C; a warm bath 1-2 hours before bed paradoxically improves sleep onset by accelerating the subsequent drop in core body temperature. Consistency: the most important sleep hygiene factor; consistent wake time is the anchor of the circadian rhythm. Caffeine: half-life of 5-7 hours; cut off by 12-1 pm for most people. Alcohol: disrupts sleep architecture in the second half of the night by suppressing REM sleep; avoid within 3 hours of bedtime. Exercise: regular moderate exercise improves sleep quality; avoid vigorous exercise within 2-3 hours of bedtime. The practical protocol: fix sleep hygiene first; add magnesium glycinate and L-theanine as a low-risk foundation; use melatonin for jet lag and circadian disruption; consider CBT-I for chronic insomnia before reaching for stronger supplements or medications.
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