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Melatonin
Circadian signal
Overview
An over-the-counter hormone supplement. Most people take far too much — the physiological dose is roughly 0.3 mg, while common retail doses are 3–10 mg.
How it works
Melatonin signals "darkness" to the body and shifts the circadian phase. It is most useful for phase-shifting (jet lag, shift work) and less reliable for chronic insomnia.
Benefits
Dosage
0.3 mg to 3 mg, 30–60 minutes before bed. Less is more — higher doses increase side effects without increasing efficacy.
Safety Profile
Side Effects
| Effect | Severity | Frequency |
|---|---|---|
| Grogginess the next morning | minor | common |
| Vivid dreams or nightmares | minor | common |
Contraindications
- Pregnancy (insufficient safety data)
- Autoimmune conditions (theoretical concern)
Research Summary
Well-studied for jet lag and circadian phase shifts. Less effective for chronic primary insomnia than CBT-I. Low doses (0.3–0.5 mg) match physiological levels better than retail 3–10 mg formulations.
Sources
Last updated: 2026-04-10
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Medical Disclaimer
This is a research summary, not medical advice. Body Signals is an independent research digest — it summarises published research for informational purposes and is not a healthcare provider. Supplements like melatonin, valerian, and magnesium can interact with prescription medications — check with your doctor or pharmacist before starting any supplement. Chronic insomnia may indicate an underlying condition (sleep apnoea, thyroid dysfunction, depression) and warrants a medical evaluation.
Need professional guidance?
If sleep issues persist despite lifestyle changes, a sleep specialist or your family doctor can help rule out underlying conditions.
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