Melatonin
A timing hormone supplement used to help reset sleep rhythms.
Melatonin is a hormone produced by the pineal gland that helps regulate the circadian rhythm and is secreted primarily in darkness. Synthesized from tryptophan via serotonin, endogenous melatonin production varies with age, season, light exposure and lifestyle factors such as stress, smoking or alcohol; synthetic melatonin supplements are used to help re‑synchronize sleep patterns when physiological secretion is altered.
Common applications include aiding sleep onset and reducing the effects of jet lag, with products available as immediate‑release (to assist falling asleep) or sustained‑release (to address nocturnal awakenings). Effects and suitable dosing vary by individual; typical guidance ranges from 1–2 mg at bedtime for sleep and specific timing or higher doses (for example, 5 mg) for pre‑travel phase adjustment, but melatonin can cause side effects and interact with medications—consult a healthcare professional if pregnant, immunocompromised, taking anticoagulants or psychotropic drugs.
At a Glance
A hormone secreted by the pineal gland, melatonin coordinates the body’s circadian rhythm and is produced mainly during periods of darkness.
Synthetic melatonin supplements are used to help re-synchronize sleep timing when endogenous secretion is altered.
| Common name | Melatonin |
|---|---|
| Scientific name | Melatonin |
| Origin | Chemical synthesis |
| Active compounds | Melatonin (N-acetyl-5-methoxytryptamine) |
| Main benefits |
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| Available forms |
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Origin & History
Melatonin is an endogenous hormone produced by the pineal gland in animals and synthesized biochemically from the amino acid tryptophan via serotonin; its secretion is regulated by light and typically rises during periods of darkness. Exogenous melatonin is manufactured through chemical synthesis and, less commonly, sourced from animal material, so origin and product quality are factors to consider when choosing a supplement.
Researchers isolated melatonin from the pineal gland and developed laboratory synthesis soon after, which allowed focused study of its role in timing the sleep‑wake cycle and related rhythms. The identification and synthetic production of melatonin made standardized preparations available that are used to influence sleep timing and circadian alignment.
Composition & Active Compounds
Melatonin appears as a small indole-derived molecule rather than a plant part; chemically it has an indolic core with a methoxy group and an amide function, formula C13H16N2O2 and molecular weight 232.278 g·mol−1. Its main chemical constituents relate to the tryptophan → serotonin → N-acetyl serotonin → melatonin pathway; these compounds matter because they form the biosynthetic sequence that produces the night-time signaling hormone.
Melatonin is the primary active compound and the most relevant substance for sleep timing and circadian regulation.
- Melatonin: endogenous hormone that signals biological night and helps regulate circadian rhythm
- Serotonin: neurotransmitter and biochemical precursor to melatonin
- N-acetyl serotonin: intermediate metabolite in the synthesis of melatonin
- Tryptophan: essential amino acid precursor to serotonin and melatonin
Related Herbs
Properties & Effects
Melatonin is traditionally known as the endogenous hormone that signals biological night and helps set the timing of the sleep–wake cycle. It is commonly used in supplement form to influence sleep timing when natural secretion is altered.
Melatonin is most notably used to support circadian rhythm regulation and aid sleep onset.
- Circadian rhythm regulation: Research suggests it may support alignment of internal sleep–wake timing with the external day–night cycle.
- Sleep onset aid: It may help people fall asleep more easily when physiological melatonin secretion is reduced.
- Jet lag mitigation: Taking melatonin at recommended times may help adjust sleep timing when crossing time zones.
- Phase-shift adjustment: Exogenous melatonin can advance or delay the timing of sleep depending on when it is taken.
- Support for delayed sleep phase and blind individuals: It may help re-establish a more regular sleep schedule in people with delayed sleep phase syndrome or without reliable light cues.
- Improved sleep in older adults: Studies suggest it may improve sleep quality in older people who have reduced natural secretion.
Dosage & How to Use
Use and timing of melatonin vary by application; the table below summarizes dosing guidance reported in clinical sources.
| Insomnia and difficulty falling asleep |
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|---|---|
| Travel — eastward (jet lag) |
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| Travel — westward (jet lag) |
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Safety, Side Effects & Contraindications
Melatonin can cause unwanted effects in some people; reported side effects include somnolence, irritability, nervousness, dizziness, allergic reactions, gastrointestinal disturbances and headache, and in many trials these were not markedly higher than placebo. The supplement can interact with several medications, so medical advice is advisable before starting melatonin if taking other drugs.
Melatonin is not recommended without professional guidance for certain groups and conditions noted by clinicians; if daytime drowsiness or other adverse effects occur, avoid driving or operating machinery and consult a healthcare professional.
- Autoimmune disease: reported contraindication; avoid unless a clinician advises otherwise
- Pregnancy: contraindicated according to the cited guidance; consult a healthcare professional
- Psychiatric disorders: listed as a contraindication in the facts; seek specialist advice
- Anticoagulants (AVK, warfarin): potential interaction; consult a clinician before use
- Psychotropic medications: potential interaction; consult a clinician before use
- Analgesics: potential interaction; consult a clinician before use
- Antiepileptic drugs: potential interaction; consult a clinician before use
Melatonin can interact with anticoagulants, psychotropic and antiepileptic drugs and is contraindicated in pregnancy, autoimmune disease and some psychiatric conditions; consult a healthcare professional before use.