Melatonin
N-acetyl-5-methoxytryptamine
TL;DR
Melatonin is a circadian timing signal, not a sedative. Low doses of 0.5-1 mg taken several hours before bed shift your body clock; the 5-10 mg doses sold in shops are supraphysiological and often no more effective for sleep onset.
Ideal For
- Jet lag, particularly eastward travel
- Delayed sleep phase syndrome and night owls trying to shift earlier
- Shift workers adapting to rotating schedules
- Older adults, whose endogenous melatonin production declines
- Blind people with non-24-hour sleep-wake disorder
Avoid If
- You are pregnant or breastfeeding — safety data is inadequate
- You take warfarin or other anticoagulants without medical review
- You have an autoimmune condition, given immunomodulatory effects
- You need to drive or operate machinery within several hours of the dose
- You are giving it to a child without paediatric advice
Frequently Asked Questions
Overview
Melatonin is a hormone produced by the pineal gland in response to darkness. Its role is to signal biological night — telling the suprachiasmatic nucleus, the body's master clock, what time it is. It is not a sedative and does not work like one.
This distinction explains most of the confusion around it. Meta-analyses of melatonin for insomnia show a modest effect: sleep onset shortened by roughly seven to twelve minutes and total sleep time increased by around eight to twenty minutes. Those are real but small effects. Where melatonin genuinely excels is circadian misalignment — jet lag, delayed sleep phase disorder, shift work, and non-24-hour sleep-wake disorder in blind people. Here the effects are substantial, and the timing of the dose matters more than the size.
The dose-response relationship is counterintuitive. Physiological nocturnal melatonin levels correspond to roughly 0.1-0.3 mg. Doses of 5-10 mg produce blood levels many times higher than the body ever generates, which does not improve efficacy and can prolong the signal into the morning, producing grogginess and, paradoxically, further circadian delay.
Timing follows the phase response curve. Taken in the early evening, several hours before habitual sleep, melatonin advances the clock, making you sleepy earlier. Taken in the early morning hours it delays the clock. This is why someone with delayed sleep phase should take a small dose around five hours before their target bedtime rather than at bedtime itself.
Product quality is a genuine problem. Analyses of commercial melatonin have found actual content ranging from a small fraction to several times the label claim, with serotonin contamination detected in a minority of products. Choose third-party tested brands.
How It Works
- Binds MT1 and MT2 receptors in the suprachiasmatic nucleus, the master circadian clock
- MT1 activation reduces the alerting signal; MT2 activation shifts circadian phase
- Signals biological darkness, entraining the sleep-wake cycle to the light-dark cycle
- Lowers core body temperature slightly, facilitating sleep onset
- Has antioxidant activity, though relevance at supplemental doses is unclear
Quick Facts
- It is a timing signal, not a sedative
- Physiological levels correspond to roughly 0.1-0.3 mg, not the 5-10 mg commonly sold
- Meta-analyses show sleep onset shortened by only about 7-12 minutes in insomnia
- Timing matters more than dose for circadian problems
- Commercial products frequently deviate substantially from label content
Benefits & Outcomes
Dream Quality Enhancement
Frequently increases dream vividness anecdotally; the trial evidence is about circadian timing, not dream quality.
Sleep Apnea Symptom Relief
Melatonin may improve sleep quality alongside treatment but does nothing for airway collapse.
Sleep Maintenance
Melatonin helps sleep onset and circadian timing far more than it helps staying asleep.
Shift Work Adaptation
Melatonin taken before daytime sleep is the best-evidenced supplement for shift workers.
Night Sweats Reduction
Improves sleep architecture disrupted by sweats; no direct thermoregulatory effect.
Jet Lag Recovery
Melatonin is the best-supported supplement for jet lag, cutting adjustment time when timed to destination bedtime.
Deep Sleep Enhancement
Best for onset and circadian timing; not a deep-sleep enhancer per se.
Faster Sleep Onset
Melatonin shortens sleep latency by roughly 7-12 minutes on average - consistent and statistically robust, but a modest real-world change.
Circadian Rhythm
Melatonin is the only supplement with strong evidence for shifting the circadian clock — when timed correctly.
Improved Sleep Quality
First-line for circadian issues, jet lag and delayed sleep phase; less effective for staying asleep.
Growth Hormone Support
Indirect but plausible: better deep sleep means better natural GH release.
Antioxidant Protection
Take it for sleep timing, not as an antioxidant strategy.
Health Concerns Addressed
Traumatic Brain Injury
Likely effective for the sleep disturbance that follows traumatic brain injury, which indirectly supports recovery.
Insomnia
Cheap and safe to try at a low dose, but do not expect much. If insomnia is persistent, CBT-I is the intervention with the real evidence.
Vivid Dreams
This pairing is mostly cautionary: melatonin is a recognized cause of vivid dreams and nightmares in some users, particularly at higher doses. If vivid dreams started with melatonin, lowering the dose or stopping is the fix.
Early Morning Waking
A phase-shifting hormone, not a sleep drug — and evening dosing pushes an already-advanced clock further in the wrong direction. Right tool for the wrong problem in most early-waking cases.
Nightmares
Melatonin is more likely suspect than solution for nightmares — vivid dreams and nightmares are recognised side effects, particularly above 3-5 mg, because it increases REM sleep where nightmares occur.
Sleep Paralysis
No supplement, including melatonin, has good evidence for sleep paralysis — the proven fixes are regular sleep and position changes.
Frequent Night Waking
Modest maintenance benefit with prolonged-release in older adults; weak for general night waking.
Heartburn & Acid Reflux
Small trials suggest melatonin improves lower esophageal sphincter pressure and heartburn scores, but the studies are few and mostly from a single research group.
Poor Sleep Quality
Worth trying at 0.5-1 mg, especially if your body clock runs late. Do not expect sedative-strength effects.
Supporting Research55 studies
The Effect of Magnesium Supplementation on Primary Insomnia in Elderly: A Double-Blind Placebo-Controlled Clinical Trial
Abbasi B, Kimiagar M, Sadeghniiat K +3 more
Magnesium supplementation significantly improved PSQI scores (p<0.05) Significant increase in sleep time by 42 minutes (p<0.001) Improved sleep efficiency from 74% to 85% (p<0.001) Reduced early morning awakening frequency (p<0.01) Increased serum melatonin concentration (p<0.05) Decreased serum cortisol levels (p<0.05) Reduced sleep onset latency by 17 minutes
The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial
Abbasi B, Kimiagar M, Sadeghniiat K +3 more
Magnesium supplementation significantly improved PSQI scores (p<0.05) Significant increase in sleep time by 42 minutes (p<0.001) Improved sleep efficiency from 74% to 85% (p<0.001) Reduced early morning awakening frequency (p<0.01) Increased serum melatonin concentration (p<0.05) Decreased serum cortisol levels (p<0.05) Reduced sleep onset latency by 17 minutes
An investigation into an evening intake of a saffron extract (affron) on sleep quality, cortisol, and melatonin concentrations in adults with poor sleep: a randomised, double-blind, placebo-controlled, multi-dose study
Lopresti AL, et al.
These results provide further validation of the sleep-enhancing effects of 28-days of saffron supplementation in adults with unsatisfactory sleep.
The effect of melatonin, magnesium, and zinc on primary insomnia in long-term care facility residents in Italy: a double-blind, placebo-controlled clinical trial
Rondanelli M, et al.
The administration of nightly melatonin, magnesium, and zinc appears to improve the quality of sleep and the quality of life in long-term care facility residents with primary insomnia.
Magnesium supplementation and sleep quality in older adults: a double-blind placebo-controlled trial
Abbasi B, Kimiagar M, Sadeghniiat K +3 more
Magnesium increased serum melatonin and improved sleep efficiency and sleep onset latency versus placebo.
Effects of tryptophan-enriched cereals consumed at breakfast and dinner on sleep, mood and melatonin in elderly people
Bravo R, Matito S, Cubero J
Tryptophan-enriched cereals increased sleep efficiency, actual sleep time and urinary melatonin while reducing depression and anxiety scores in older adults.
The Effect of Magnesium Supplementation on Primary Insomnia in Elderly
Abbasi B, Kimiagar M, Sadeghniiat K +1 more
Magnesium supplementation significantly improved PSQI scores (p<0.05) Significant increase in sleep time by 42 minutes (p<0.001) Improved sleep efficiency from 74% to 85% (p<0.001) Reduced early morning awakening frequency (p<0.01) Increased serum melatonin concentration (p<0.05) Decreased serum cortisol levels (p<0.05) Reduced sleep onset latency by 17 minutes
Effects of nocturnal light exposure on melatonin suppression: a systematic review and meta-analysis
Tahkamo L, Partonen T, Pesonen AK
Short-wavelength evening light produced substantial dose-dependent suppression of endogenous melatonin secretion.
Creatine supplementation, sleep deprivation, cortisol, melatonin and behavior
McMorris T, et al.
In sleep-deprived participants, creatine supplementation (20 g/day for 7 days) attenuated the decline in performance on complex tasks requiring executive function and reduced the rise in salivary cortisol during 24 hours of sleep deprivation, without altering melatonin rhythm; simple tasks were unaffected.
The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial
Abbasi B, Kimiagar M, Sadeghniiat K +3 more
Magnesium significantly increased sleep time and sleep efficiency and reduced Insomnia Severity Index scores, sleep onset latency and early morning awakening compared with placebo. Serum renin and melatonin increased and serum cortisol decreased in the magnesium group.
Tryptophan and vitamin B6 status in relation to melatonin synthesis: a randomized controlled trial
Hudson C, Hudson SP, Hecht T +1 more
Tryptophan supplementation increased overnight melatonin metabolite excretion and improved sleep continuity.
Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders
Auld F, Maschauer EL, Morrison I +2 more
Melatonin showed the strongest evidence for reducing sleep onset latency in primary insomnia and for circadian rhythm disorders.
Comparative effects of pharmacological interventions for the acute and long-term management of insomnia disorder in adults: a systematic review and network meta-analysis
De Crescenzo F, et al.
Melatonin, ramelteon, and non-licensed drugs did not show overall material benefits.
Melatonin supplementation and oxidative DNA damage repair capacity among night shift workers: a randomised placebo-controlled trial
Melatonin supplementation improves oxidative DNA damage repair capacity among night shift workers.
Effectiveness of ramelteon for insomnia symptoms in older adults with obstructive sleep apnea: a randomized placebo-controlled pilot study
Gooneratne NS, Gehrman P, Gurubhagavatula I +1 more
Ramelteon treatment was associated with a statistically significant difference in sleep onset latency (SOL) as measured by polysomnography of 28.5 min compared to placebo
Melatonin for preventing and treating jet lag
Herxheimer A, Petrie KJ
Melatonin for preventing and treating jet lag
Adjuvant use of melatonin for pain management in endometriosis-associated pelvic pain: a randomized double-blinded, placebo-controlled trial
Soderman L, Bottiger Y, Edlund M +2 more
The difference in endometriosis-associated pain between the groups showed to be non-significant statistically as well as clinically
Melatonin in autism spectrum disorders: a systematic review and meta-analysis
Rossignol DA, Frye RE
Melatonin supplementation in ASD improved sleep duration and sleep onset latency with minimal side effects.
Melatonin and delirium in the intensive care units: a systematic review and meta-analysis of randomized controlled trials
Lakbar I, et al.
Compared to placebo, melatonin does not reduce delirium incidence in critically ill patients.
Melatonin for shift work sleep disorder and circadian adaptation: a Cochrane review
Liira J, Verbeek JH, Costa G +4 more
Melatonin increased sleep length after night shift by around 24 minutes but did not improve sleep onset latency or alertness on shift
Efficacy of melatonin for chronic insomnia: Systematic reviews and meta-analyses
Melatonin produced small improvements in sleep onset latency and sleep quality in chronic insomnia.
Is the addition of sublingual melatonin to omeprazole superior to omeprazole alone in the management of gastroesophageal reflux disease symptoms: a clinical trial
Malekpour H, Noori A, Abdi S +2 more
The present study aimed to investigate whether the addition of sublingual melatonin to omeprazole was effective in the treatment of gastro gastroesophageal reflux disease symptoms.
Antioxidants for female subfertility
Showell MG, Mackenzie-Proctor R, Jordan V +1 more
low-quality evidence shows no difference in a lower dose of melatonin being associated with an increased live-birth rate compared with higher-dose melatonin (OR 0.94, 95% CI 0.41 to 2.15; P = 0.89, I2 = 0%; 2 RCTs, 140 women)
Sleep Problems and Melatonin Prescription After Concussion Among Youth Athletes
Howell DR
Melatonin prescription was not associated with faster symptom recovery.
Melatonin and agomelatine for preventing seasonal affective disorder
Nussbaumer-Streit B, Greenblatt A, Kaminski-Hartenthaler A
Given the uncertain evidence on agomelatine and the absence of studies on melatonin, no conclusion about efficacy and safety of agomelatine and melatonin for prevention of SAD can currently be drawn.
Analgesic and sedative effects of melatonin in temporomandibular disorders: a double-blind, randomized, parallel-group, placebo-controlled study
Vidor LP, et al.
This study provides additional evidence supporting the analgesic effects of melatonin on pain scores and analgesic consumption in patients with mild-to-moderate chronic myofascial TMD pain.
Melatonin for delirium prevention in hospitalized patients: a systematic review and meta-analysis
Khaing K, Nair BR
Melatonin reduced delirium incidence in medical inpatients but not consistently in surgical populations.
Melatonin: can it stop the ringing?
Melatonin is associated with a statistically significant decrease in tinnitus intensity and improved sleep quality in patients with chronic tinnitus.
Melatonin as add-on treatment for epilepsy
Brigo F, Igwe SC, Del Felice A
No conclusions could be drawn regarding the role of melatonin as add-on treatment for epilepsy.
Efficacy of melatonin for sleep disturbance in middle-aged primary insomnia: a double-blind, randomised clinical trial
Melatonin improved sleep quality and continuity versus placebo in middle-aged primary insomnia.
Ramelteon-induced nightmares: a case report
Shah C, Kablinger A
Shortly after initiation of ramelteon, he described vivid nightmares leading to discontinuation of ramelteon. The nightmares ameliorated with ramelteon discontinuation.
The efficacy and safety of exogenous melatonin for primary sleep disorders: a meta-analysis
Buscemi N, Vandermeer B, Hooton N +6 more
Melatonin reduced sleep onset latency by a small but statistically significant amount, with no significant effect on sleep efficiency or total sleep time.
Effect of tart cherry juice (Prunus cerasus) on melatonin levels and enhanced sleep quality
Howatson G, et al.
consumption of a tart cherry juice concentrate provides an increase in exogenous melatonin that is beneficial in improving sleep duration and quality
Pharmacotherapies for sleep disturbances in dementia
McCleery J, et al.
From single studies, we found no difference between melatonin and placebo groups for sleep efficiency, time awake after sleep onset, or number of night-time awakenings.
Effect of melatonin on incidence of delirium among patients with hip fracture: a multicentre, double-blind randomized controlled trial
de Jonghe A, van Munster BC, Goslings JC
Melatonin did not reduce delirium incidence compared with placebo.
Jet lag
Herxheimer A
Melatonin taken close to target bedtime reduced subjective jet lag after eastward and westward flights
Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole
Pereira RS
Melatonin has known inhibitory activities on gastric acid secretion and nitric oxide biosynthesis.
Pharmacological treatments of REM sleep behaviour disorder in synucleinopathies: a systematic review of effectiveness and safety
Sleep Medicine review authors
Clonazepam and melatonin remain the principal treatments in practice, but evidence was limited and inconsistent.
The Effects of Pharmacological Treatment of Nightmares: A Systematic Literature Review and Meta-Analysis of Placebo-Controlled, Randomized Clinical Trials
Pharmacological treatments for nightmares, including melatonergic agents, produced only small effects versus placebo.
Melatonin for sleep disorders
Ferracioli-Oda, E., Qawasmi, A.
Melatonin reduced sleep onset latency and increased total sleep time and sleep quality across primary sleep disorders.
Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole
Pereira RS
Complete regression of GERD symptoms occurred in 100% of patients that used the dietary supplementation, and in 65.7% of the patients treated with omeprazole.
The effect of prolonged-release melatonin on sleep measures and psychomotor performance in elderly patients with insomnia
Luthringer R, Muzet M, Zisapel N +1 more
the PRM group had significantly shorter sleep onset latency (9 min; P = 0.02) compared with the placebo group
Meta-analysis: melatonin for the treatment of primary sleep disorders
Ferracioli-Oda E, et al.
This meta-analysis demonstrates that melatonin decreases sleep onset latency, increases total sleep time and improves overall sleep quality.
Comparative study to determine the optimal melatonin dosage form for the alleviation of jet lag
Suhner A, Schlagenhauf P
Fast-release 5 mg melatonin gave the best subjective jet lag relief among dosage forms tested
Melatonin for the prevention and treatment of jet lag
Herxheimer A, Petrie KJ
Melatonin taken close to target bedtime decreased jet lag from flights crossing five or more time zones.
Effect of exogenous melatonin on endogenous melatonin secretion and circadian phase: a systematic review
Burgess HJ, Emens JS
Low-dose melatonin taken in the early evening advanced dim light melatonin onset
Efficacy and Safety of Melatonin as Prophylaxis for Migraine in Adults: A Meta-analysis
Puliappadamb HM, Maiti R, Mishra A +1 more
Melatonin therapy in migraine was associated with a significantly higher responder rate when compared to both placebo and standard therapy (OR = 1.84; 95% CI: 1.08 to 3.14; P = .03).
Prolonged-release melatonin improves sleep quality and morning alertness in insomnia patients aged 55 years and older and has no withdrawal effects
Lemoine P, et al.
PR-melatonin is the first drug shown to significantly improve quality of sleep and morning alertness in primary insomnia patients aged 55 years and older.
Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis
Buscemi N, Vandermeer B, Hooton N +6 more
Melatonin did not produce a clinically meaningful reduction in sleep onset latency in secondary sleep disorders or sleep restriction.
Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials
Fatemeh G, et al.
We found that the treatment with exogenous melatonin has positive effects on sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI) in adult.
Is the addition of sublingual melatonin to omeprazole superior to omeprazole alone in the management of gastroesophageal reflux disease symptoms: a clinical trial
Malekpour H, et al.
The combination of sublingual melatonin (3 mg/day) with omeprazole (20 mg/day) may be more effective than omeprazole (20 mg/day) alone in the treatment of gastroesophageal reflux disease.
Efficacy of prolonged release melatonin in insomnia patients aged 55-80 years: quality of sleep and next-day alertness outcomes
Wade AG, Ford I, Crawford G +4 more
Prolonged-release melatonin significantly improved sleep quality and morning alertness versus placebo, with no rebound insomnia.
Human phase response curves to three days of daily melatonin: 0.5 mg versus 3.0 mg
Burgess HJ, Revell VL, Molina TA +1 more
Both doses produced comparable circadian phase advances and delays depending on timing relative to circadian phase.
Dose finding of melatonin for chronic idiopathic childhood sleep onset insomnia: an RCT
van Geijlswijk IM, van der Heijden KB, Egberts ACG +2 more
All melatonin doses advanced sleep onset and dim light melatonin onset compared with placebo, with no dose-response relationship.
Adverse Events Associated with Melatonin for the Treatment of Primary or Secondary Sleep Disorders: A Systematic Review
Besag FMC, Vasey MJ, Lao KSJ +1 more
Reported adverse events were generally mild and comparable to placebo, most commonly daytime sleepiness, headache, dizziness and nausea.
Safety Information
Potential Side Effects
Generally safe for short-term use. May cause daytime drowsiness or vivid dreams
Contraindications
Autoimmune diseases, seizure disorders, depression
Drug Interactions
- Sedatives
- Blood thinners
- Diabetes medications
- Immunosuppressants
- Birth control
Pregnancy & Breastfeeding
Pregnancy: insufficient_data
Breastfeeding: insufficient_data
Dosage Guidelines
Dosage Used in Studies
0.5-5 mg
Best Time to Take
30-60 minutes before bed
Best Form
Immediate or sustained-release tablets
Bioavailability
Rapid absorption with oral administration. Significant first-pass metabolism. Sustained-release for sleep maintenance vs immediate for sleep onset.
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.