Quick Reference
- Scientific Rating
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4.0/ 5.0
- Primary Mechanism
- Binds MT1 and MT2 melatonin receptors in the suprachiasmatic nucleus of the hypothalamus to regulate circadian rhythm and promote sleep onset
- Standardized Form
- Immediate-release or extended-release tablet/capsule, typically formulated between 0.5 mg and 10 mg
Melatonin is synthesized and released by the pineal gland in response to darkness, serving as the body's primary internal signal for the timing of sleep within the circadian rhythm. As an over-the-counter supplement, it is among the most widely used sleep aids globally and has one of the largest bodies of randomized, placebo-controlled trial evidence of any sleep-support ingredient. A notable disconnect exists between clinical dosing and commercial products: most trials showing benefit use doses in the 0.5-5 mg range, while many supplements sold at retail contain 5-10 mg or more per serving, doses not clearly associated with additional benefit and more frequently linked to next-day grogginess.
Table of Contents
Clinical Summary
A meta-analysis of 19 randomized, placebo-controlled trials (1,683 subjects) found melatonin significantly reduced sleep latency and increased total sleep time compared to placebo, with larger effects observed at higher doses and longer treatment duration, though the clinically meaningful dose ceiling for most healthy adults is lower than many commercial products suggest.
Dosage Guidelines
0.5-5 mg taken 30-60 minutes before intended bedtime is generally sufficient in clinical trials; doses above 5 mg have not consistently shown additional benefit for sleep onset.
Safety & Side Effects
Next-day grogginess, vivid dreams, headache, and mild dizziness have been reported, particularly at higher doses.
Known Interactions
May interact with sedatives (additive drowsiness), blood thinners (theoretical mild effect), and immunosuppressant medications.
Scientific References
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1
https://pubmed.ncbi.nlm.nih.gov/23691095/Source: pubmed.ncbi.nlm.nih.gov
Medical Disclaimer
The information provided in this clinical review is for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
*These statements have not been evaluated by the Food and Drug Administration (FDA). This product or ingredient is not intended to diagnose, treat, cure, or prevent any disease.
Always consult your physician or other qualified health provider with any questions you may have regarding a medical condition, or before beginning any new diet, fitness, supplement, or treatment regimen, especially if you have pre-existing medical conditions or are taking prescribed medications.