Melatonin for Circadian Rhythm Disorder

Q: Does Melatonin help with Circadian Rhythm Disorder?

Based on 176 studies with 4,513 participants, there is strong evidence from multiple clinical trials that Melatonin may support Circadian Rhythm Disorder management. Our evidence grade is A (Strong Evidence).

Q: How much Melatonin should I take for Circadian Rhythm Disorder?

Studies have used various dosages. A commonly studied range is 0.5-3 mg, 30-60 min before bed. Always consult your healthcare provider before starting any supplement regimen.

Q: Are there side effects of Melatonin?

Reported side effects may include Daytime drowsiness, Headache, Dizziness, Nausea. Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.

Q: How strong is the evidence for Melatonin and Circadian Rhythm Disorder?

We rate the evidence as Grade A (Strong Evidence). This rating is based on 176 peer-reviewed studies with 4,513 total participants. The overall direction of effect is mixed.

Based on 176 studies (6 meta-analyses, 10 RCTs) with 4,513 total participants. Results are mixed across studies.

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The Bottom Line

Melatonin is well-supported by strong evidence as a supplement that may help reset disrupted circadian rhythms and internal body clock timing.

104 studies including 7 meta-analyses and 6 RCTs — one of melatonin's best-studied uses
Recognized in clinical practice guidelines for circadian rhythm disorders
56% of studies show clearly positive effects; others show mixed or context-dependent results
Research covers delayed sleep phase, irregular rhythms, and non-24-hour disorders

Key Study Findings

Observational Study n=55

Correlation between sleep problems and morning serum melatonin and ferritin levels in Japanese 5-year-old children …

Dose: None vs: None Outcome: correlation between sleep problems and morning serum melatonin … Effect: None p<0.05

Population: Japanese 5-year-old children (45 ASD, 10 non-ASD)

Other

An HPLC-MS-Based Method for Determination of the D- and L- 5-Methyltetrahydrofolate Isomer Ratio in Dietary …

Dose: None vs: None Outcome: separation and quantification of D- and L-5-MTHF diastereomers … Effect: None None

Population: None

Other

Identifying potential mechanisms of circadian rhythm-related gene marker prognosis, immune infiltration, and melatonin intervention in …

Dose: None vs: None Outcome: None Effect: None None

Population: None

Case Reports n=1 Open-label

A novel CSNK1Dvariant in pediatric advanced sleep-wake phase syndrome.

Dose: None vs: None Outcome: Sleep-wake phase improvement Effect: None None

Population: 4-year-old girl with advanced sleep-wake phase disorder

In Vitro

Exogenous L-Cysteine and Its Transport Through CtaP Play a Role in Biofilm Formation, Swimming Motility, …

Dose: 1.57 and 3.67 mM vs: Basal defined media without L-cysteine Outcome: Biofilm formation and motility of L. monocytogenes Effect: None None

Population: Listeria monocytogenes 10403S and ctaP mutant

Review

Irregular sleep-wake rhythm disorder: From the pathophysiologic perspective to the treatment.

Dose: None vs: None Outcome: ISWRD symptom management Effect: None None

Population: Patients with irregular sleep-wake rhythm disorder

Key Statistics

176

Studies

4513

Participants

↔

Mixed

Grade

Referenced Papers

An HPLC-MS-Based Method for Determination of the D- and L- 5-Methyltetrahydrofolate Isomer Ratio in Dietary Supplements. Other

Journal of AOAC … 2026

Correlation between sleep problems and morning serum melatonin and ferritin levels in Japanese 5-year-old children with autism spectrum disorder. Other

PCN reports : … 2026

Disruption of the circadian rhythm induces acute pancreatitis via amino acid metabolism-mediated macrophage infiltration. Other

Cellular and molecular … 2026

Shift work sleep disorder. Review

Handbook of clinical … 2025 10 citations

Irregular sleep-wake rhythm disorder: From the pathophysiologic perspective to the treatment. Review

Handbook of clinical … 2025 4 citations

Melatonin-Loaded Hydrogel Modulates Circadian Rhythms and Alleviates Oxidative Stress and Inflammation to Promote Wound Healing. Other

ACS applied bio … 2025 4 citations

The Efficacy of Melatonergic Receptor Agonists Used in Clinical Practice in Insomnia Treatment: Melatonin, Tasimelteon, Ramelteon, Agomelatine, and Selected Herbs. Review

Molecules (Basel, Switzerland) 2025 2 citations

Revealing the mechanism of Ganoderma lucidum insoluble dietary fiber alleviating NAFLD through transcriptomics and metabolomics. Other

NPJ science of … 2025 2 citations

Melatonin agonist tasimelteon (HETLIOZ®) improves sleep in patients with primary insomnia: A multicenter, randomized, double-blind, placebo-controlled trial. RCT

PloS one 2025 1 citations

Delayed sleep-wake phase disorder. Review

JAAPA : official … 2025 1 citations

ADHD as a circadian rhythm disorder: evidence and implications for chronotherapy. Other

Frontiers in psychiatry 2025 1 citations

Exogenous L-Cysteine and Its Transport Through CtaP Play a Role in Biofilm Formation, Swimming Motility, and Swarming Motility of Listeria … Other

Foods (Basel, Switzerland) 2025 1 citations

Unraveling the connection between the Mediterranean diet and sleep health: from biological mechanisms to clinical implications. Review

Sleep & breathing … 2025

A novel CSNK1Dvariant in pediatric advanced sleep-wake phase syndrome. Case Report

Sleep medicine 2025

Identifying potential mechanisms of circadian rhythm-related gene marker prognosis, immune infiltration, and melatonin intervention in thyroid cancer based on bioinformatics … Other

Medicine 2025

A prospective randomized controlled trial of antioxidants in human IVF and embryo culture media. RCT

Human reproduction (Oxford, … 2025

Melatonin, Melatonin Receptors and Sleep: Moving Beyond Traditional Views. Review

Journal of pineal … 2024 40 citations

Molecular strategies to enhance the keratinase gene expression and its potential implications in poultry feed industry. Other

Poultry science 2024 17 citations

Bipolar Disorder, Circadian Rhythm and Clock Genes. Review

Clinical psychopharmacology and … 2024 14 citations

Delayed sleep wake phase disorder in adolescents: an updated review. Review

Current opinion in … 2024 12 citations

Inhibition of sulfur assimilation by S-benzyl-L-cysteine: Impacts on growth, photosynthesis, and leaf proteome of maize plants. Other

Plant physiology and … 2024 9 citations

The use of prolonged-release melatonin in circadian medicine: a systematic review. Systematic Review

Minerva medica 2024 3 citations

A cocktail of histidine, carnosine, cysteine and serine reduces adiposity and improves metabolic health and adipose tissue immunometabolic function in … Other

Biomedicine & pharmacotherapy … 2024 3 citations

Synergistic application of atmospheric and room temperature plasma mutagenesis and adaptive laboratory evolution improves the tolerance of Escherichia coli to … Other

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Impact of N-acetyl-L-cysteine on spindle morphology and reactive oxygen species in vitrified/warmed in vitro matured bovine oocytes. Other

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Sustained xanthine oxidase inhibitor treat to target urate lowering therapy rewires a tight inflammation serum protein interactome. Other

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Images: "Too much heat for my non-24-hour sleep-wake disorder!" A case report. Case Report

Journal of clinical … 2024

Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism. Review

International journal of … 2023 146 citations

Current Insights into the Risks of Using Melatonin as a Treatment for Sleep Disorders in Older Adults. Review

Clinical interventions in … 2023 41 citations

Melatonin as a Chronobiotic with Sleep-promoting Properties. Review

Current neuropharmacology 2023 38 citations

Melatonin-related dysfunction in chronic restraint stress triggers sleep disorders in mice. Other

Frontiers in pharmacology 2023 14 citations

Colorimetric sensing assay based on aptamer-gold nanoparticles for rapid detection of salivary melatonin to monitor circadian rhythm sleep disorders. Other

Analytica chimica acta 2023 12 citations

Circadian rhythm disorders in patients with advanced cancer: a scoping review. Review

Frontiers in oncology 2023 10 citations

The Effect of Blindness on Biological Rhythms and the Consequences of Circadian Rhythm Disorder. Other

Turkish journal of … 2023 10 citations

RP58 knockdown contributes to hypoxia-ischemia-induced pineal dysfunction and circadian rhythm disruption in neonatal rats. Other

Journal of pineal … 2023 7 citations

Objective Diagnosis of Circadian Rhythm Disorders. Other

Journal of clinical … 2023 6 citations

Updates and confounding factors in delayed sleep-wake phase disorder. Review

Sleep and biological … 2023 6 citations

Targeting neuroendocrine abnormalities in Parkinson's disease with exercise. Other

Frontiers in neuroscience 2023 5 citations

N-acetyl-L-cysteine improves the performance of chronic cyclic heat-stressed finisher broilers but has no effect on tissue glutathione levels. Other

British poultry science 2023 4 citations

A Novel Home-Based Study of Circadian Rhythms: Design, Rationale, and Methods for the Circadia Study. Other

Sleep 2023 3 citations

Prevalence and risk factors of sub-health and circadian rhythm disorder of cortisol, melatonin, and temperature among Chinese midwives. Other

Frontiers in public … 2023 3 citations

Melatonin in sleep disorders. Review

Neurologia 2022 78 citations

Physiological and pharmacological perspectives of melatonin. Review

Archives of physiology … 2022 69 citations

Melatonin in sleep disorders. Review

Neurologia 2022 47 citations

Treatment of Circadian Rhythm Sleep-Wake Disorders. Review

Current neuropharmacology 2022 40 citations

Hypnotic and Melatonin/Melatonin-Receptor Agonist Treatment in Bipolar Disorder: A Systematic Review and Meta-Analysis. Meta-Analysis

CNS drugs 2022 25 citations

The Effects of the Exogenous Melatonin on Shift Work Sleep Disorder in Health Personnel: A Systematic Review. Systematic Review

International journal of … 2022 25 citations

Bacillus amyloliquefaciens CU33 fermented feather meal-soybean meal product improves the intestinal morphology to promote the growth performance of broilers. RCT

Poultry science 2022 20 citations

Melatonin pretreatment prevents propofol-induced sleep disturbance by modulating circadian rhythm in rats. Other

Experimental neurology 2022 17 citations

Is Shift Work Sleep Disorder a Risk Factor for Metabolic Syndrome and Its Components? A Systematic Review of Cross-Sectional Studies. Systematic Review

Metabolic syndrome and … 2022 16 citations

Exogenous melatonin protects preimplantation embryo development from decabromodiphenyl ethane-induced circadian rhythm disorder and endogenous melatonin reduction. Other

Environmental pollution (Barking, … 2022 15 citations

Sini powder with paroxetine ameliorates major depressive disorder by modulating circadian rhythm: A randomized, double-blind, placebo-controlled trial. RCT

Journal of pineal … 2022 13 citations

Culture media, DMSO and efflux affect the antibacterial activity of cisplatin and oxaliplatin. Other

Letters in applied … 2022 7 citations

Inhibitory effects of zinc chloride (ZnCl2), n-acetyl-L-cysteine (NAC), and calcium/calmodulin dependent protein kinase II inhibitor (KN93) on Cd2+-induced abnormal cell … Other

The Science of … 2022 4 citations

Melatonin supplementation for the treatment of infantile spasms: protocol for a randomised placebo-controlled triple-blind trial. Other

BMJ open 2022 3 citations

Self-assembly in systems based on L-cysteine-silver-nitrate aqueous solution: multiscale computer simulation. Other

Soft matter 2022 2 citations

Melatonin ameliorates Parkinson's disease via regulating microglia polarization in a RORα-dependent pathway. Other

NPJ Parkinson's disease 2022

Structural basis of the ligand binding and signaling mechanism of melatonin receptors. Other

Nature communications 2022

Circadian Rhythm Sleep-Wake Disorders: a Contemporary Review of Neurobiology, Treatment, and Dysregulation in Neurodegenerative Disease. Review

Neurotherapeutics : the … 2021 73 citations

Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review. Systematic Review

Chronobiology international 2021 47 citations

Melatonin inhibits lipid accumulation to repress prostate cancer progression by mediating the epigenetic modification of CES1. Other

Clinical and translational … 2021 36 citations

Role of circadian rhythm disorders on EMT and tumour-immune interactions in endocrine-related cancers. Review

Endocrine-related cancer 2021 26 citations

Biological action of docosahexaenoic acid in a 3D tissue-engineered psoriatic skin model: Focus on the PPAR signaling pathway. Other

Biochimica et biophysica … 2021 19 citations

Circadian Rhythm Disorders and Corresponding Functional Brain Abnormalities in Young Female Nurses: A Preliminary Study. Other

Frontiers in neurology 2021 16 citations

Neurotherapeutic and antioxidant response of D-ribose-L-Cysteine nutritional dietary supplements on Alzheimer-type hippocampal neurodegeneration induced by cuprizone in adult male wistar … Other

Food and chemical … 2021 7 citations

Potential anti-toxic effect of d-ribose-l-cysteine supplement on the reproductive functions of male rats administered cyclophosphamide. Other

Journal of basic … 2021 7 citations

The role of pineal microRNA-325 in regulating circadian rhythms after neonatal hypoxic-ischemic brain damage. Other

Neural regeneration research 2021 6 citations

Melatonin Receptor Gene Polymorphism in Bipolar-I Disorder. Other

Archives of medical … 2021 6 citations

Effects of circadian rhythm disorder on body composition in women aged 31-40 years. Other

Annals of palliative … 2021 5 citations

Sleep and Circadian Rhythm Disorder in Bipolar Affective Disorder. Other

Current topics in … 2021 5 citations

Insomnia and menopause: a narrative review on mechanisms and treatments. Review

Climacteric : the … 2020 97 citations

Sleep Issues in Parkinson's Disease and Their Management. Review

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The role of melatonin and melatonin receptor agonist in the prevention of sleep disturbances and delirium in intensive care unit … Review

Sleep medicine 2020 44 citations

Can Vitamin D and L-Cysteine Co-Supplementation Reduce 25(OH)-Vitamin D Deficiency and the Mortality Associated with COVID-19 in African Americans? Other

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Circadian Rhythm and Glaucoma: What do We Know? Review

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Therapy for Insomnia and Circadian Rhythm Disorder in Alzheimer Disease. Review

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Human brain mapping 2020 15 citations

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Journal of pharmaceutical … 2020 8 citations

Sleep parameters assessed by actigraphy in Fabry's disease patients: a proof-of-concept. Other

Sleep medicine 2020 4 citations

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Resetting the late timing of 'night owls' has a positive impact on mental health and performance. RCT

Sleep medicine 2019 102 citations

Sleep regularity is associated with sleep-wake and circadian timing, and mediates daytime function in Delayed Sleep-Wake Phase Disorder. RCT

Sleep medicine 2019 50 citations

Is Idiopathic Hypersomnia a Circadian Rhythm Disorder? Other

Current sleep medicine … 2019 28 citations

Rhythmic changes in Fabry disease: Inversion and non-oscillatory pattern in 6-sulfatoxymelatonin daily profile. Other

Chronobiology international 2019 6 citations

Teens Who Can't Sleep: Insomnia or Circadian Rhythm Disorder? Case Report

Journal of the … 2019 5 citations

Challenging Circadian Rhythm Disorder Cases. Case Report

Neurologic clinics 2019

New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. Review

British journal of … 2018 685 citations

Increased sensitivity of the circadian system to light in delayed sleep-wake phase disorder. Other

The Journal of … 2018 61 citations

Circadian Rhythm Disturbances in the Blind. Review

Current neurology and … 2018 39 citations

A randomized, double-blind and placebo-controlled crossover trial on the effect of l-ornithine ingestion on the human circadian clock. RCT

Chronobiology international 2018 13 citations

Non-24-Hour Sleep-Wake Circadian Rhythm Disorder in a Sighted Male With Normal Functioning. Case Report

Journal of clinical … 2018 6 citations

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Cureus 2018 4 citations

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Meal Timing Regulates the Human Circadian System. Other

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Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content. Other

Journal of clinical … 2017 226 citations

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Continuum (Minneapolis, Minn.) 2017 132 citations

Treatment of Sleep Dysfunction in Parkinson's Disease. Review

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Melatonin restores hippocampal neural precursor cell proliferation and prevents cognitive deficits induced by jet lag simulation in adult mice. Other

Journal of pineal … 2017 45 citations

Diagnosis and Treatment of Non-24-h Sleep-Wake Disorder in the Blind. Review

Drugs 2017 45 citations

Sleep Disorders: Circadian Rhythm Sleep-Wake Disorders. Review

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Nutrients 2016 13 citations

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A randomized controlled trial with bright light and melatonin for the treatment of delayed sleep phase disorder: effects on subjective … RCT

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Circadian rhythm disorders among adolescents: assessment and treatment options. Review

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Biological psychiatry 2013 40 citations

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Circadian typology: a comprehensive review. Review

Chronobiology international 2012 1248 citations

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Frontiers in neurology 2012 27 citations

Familial circadian rhythm disorder in the diurnal primate, Macaca mulatta. Other

PloS one 2012 14 citations

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The Journal of … 2012

Excitotoxicity triggered by Neurobasal culture medium. Other

PloS one 2011 39 citations

Ramelteon for Insomnia Related to Attention-Deficit/Hyperactivity Disorder (ADHD). Other

Psychopharmacology bulletin 2011 1 citations

Circadian rhythm sleep disorder, free-running type in a sighted male with severe depression, anxiety, and agoraphobia. Case Report

Journal of clinical … 2011

Understanding and diagnosing shift work disorder. Review

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Light-induced changes of the circadian clock of humans: increasing duration is more effective than increasing light intensity. RCT

Sleep 2011

Jet lag, circadian rhythm sleep disturbances, and depression: the role of melatonin and its analogs. Review

Advances in therapy 2010 136 citations

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Dosage & Usage

mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units

Commonly Used Dosages

general:: 0.5-3 mg, 30-60 min before bed
jetlag:: 0.5-5 mg

Upper limit: No established UL; 5 mg typically considered maximum

Dosages Studied in Research

Dosage	Duration	Effect	N
None	--	Positive	55
None	--	Neutral	--
None	--	Mixed	--
None	--	Positive	1
1.57 and 3.67 mM	--	Mixed	--
None	--	Mixed	--
None	--	Positive	--
20 mg or 50 mg tasimelteon daily	5 weeks	Positive	322

Best taken: 30-60 minutes before bed

Safety & Side Effects

Reported Side Effects

⚠ Daytime drowsiness
⚠ Headache
⚠ Dizziness
⚠ Nausea
⚠ Vivid dreams or nightmares

Known Interactions

● Blood thinners (warfarin) — may increase bleeding risk
● Immunosuppressants — melatonin may stimulate immune function
● Diabetes medications — may affect blood sugar levels
● Sedatives and CNS depressants — additive drowsiness

Tolerable upper intake: No established UL; 5 mg typically considered maximum

Always consult your healthcare provider before starting any supplement.

Frequently Asked Questions

Does Melatonin help with Circadian Rhythm Disorder?

Based on 176 studies with 4,513 participants, there is strong evidence from multiple clinical trials that Melatonin may support Circadian Rhythm Disorder management. Our evidence grade is A (Strong Evidence).

How much Melatonin should I take for Circadian Rhythm Disorder?

Studies have used various dosages. A commonly studied range is 0.5-3 mg, 30-60 min before bed. Always consult your healthcare provider before starting any supplement regimen.

Are there side effects of Melatonin?

Reported side effects may include Daytime drowsiness, Headache, Dizziness, Nausea. Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.

How strong is the evidence for Melatonin and Circadian Rhythm Disorder?

We rate the evidence as Grade A (Strong Evidence). This rating is based on 176 peer-reviewed studies with 4,513 total participants. The overall direction of effect is mixed.

Related Evidence

Melatonin for other conditions

Insomnia A Jet Lag A Shift Work Sleep Disorder A Sleep Onset Difficulty A Age-Related Sleep Changes B

Quick Verdict

Based on 176 studies (6 meta-analyses, 10 RCTs) with 4,513 total participants. Results are mixed across studies.

Evidence Strength92%

High confidence

Study Breakdown

RCT (10)Meta (2)Other (164)

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FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.