Melatonin
Best-in-class: Melaton-3
The body's darkness/sleep-timing hormone. Best understood as a circadian signal — not a sedative.
Melatonin quick facts
| Suggested dose | 0.5–3 mg 30–60 min before bed; use the lowest effective dose. |
| How often | Daily, or only on disrupted nights |
| Who it's for | Jet lag, shift work, delayed sleep timing, and older adults with low output. |
| Best-in-class brand | Melaton-3 |
Almost everyone takes far too much, far too late. Doses in the range of a few tenths of a milligram to one milligram match physiology and work as well or better than ten milligrams for sleep onset — the high-dose versions mostly buy grogginess the next morning. For jet lag or a delayed body clock, the timing is the active ingredient: taken several hours before your target bedtime it advances the clock, taken in the morning it delays it. It's not habit-forming, but it also isn't a treatment for insomnia caused by anything other than mistimed rhythm.
How Melatonin actually works
Melatonin is a timing signal, not a sedative. The pineal gland releases it when light stops hitting the retina, and it binds MT1 and MT2 receptors in the suprachiasmatic nucleus — the master clock — where MT1 damps the wake-promoting signal and MT2 shifts the phase of the clock itself. Which direction it shifts depends entirely on timing relative to your own rhythm, not on dose. Physiological release is small; typical supplement doses are many times higher than the body ever produces, which saturates the receptors without improving the signal.
Where to get Melatonin
Buy Melaton-3 at Thorne →The evidence for Melatonin
Graded by what exists behind each claim.
✅ Clinically validated
- Meta-analyses show it shortens time to fall asleep and helps reset circadian rhythm (jet lag, shift work, delayed sleep phase).
- Low doses are effective; more is not better for sleep onset.
📊 Correlative data
- Endogenous melatonin declines with age, tracking with more fragmented sleep.
🧪 Theoretical / extrapolated benefits
- Antioxidant and longevity roles are actively researched but separate from — and less established than — its circadian sleep effect.
How to read these tiers: they say how much human evidence exists, not how well something works — and ✗ flags harm, never a disappointing trial. How the evidence tiers work →
What Melatonin actually does
Melatonin is a timing signal, not a sedative, and almost every mistake made with it follows from confusing the two. The pineal gland converts serotonin to N-acetylserotonin and then to melatonin under control of the suprachiasmatic nucleus, which is itself set by light reaching intrinsically photosensitive retinal ganglion cells. The hormone's job is to tell the rest of the body what time the clock thinks it is.
Two receptors, two jobs, and they are not the same job. MT1 receptors on suprachiasmatic neurons acutely suppress their firing, which is the mild sleep-promoting effect. MT2 receptors mediate the phase-shifting effect — moving the clock earlier or later depending on when the dose arrives. Both are G protein-coupled and both desensitize with sustained high concentrations, which is an argument against large nightly doses that nobody makes on a label.
The phase response curve is the single most important and least known fact about this molecule. Melatonin given in the hours before habitual sleep advances the clock; given in the early morning it delays it; given in the middle of the biological night it does little. Human phase response curves have been mapped for 0.5 mg and 3.0 mg, and the smaller dose produces a comparable or cleaner phase shift Burgess 2010. Timing, not dose, is the active variable.
Physiological and pharmacological concentrations are three orders of magnitude apart. Peak endogenous nocturnal plasma melatonin is on the order of 50 to 200 picograms per milliliter. A 3 mg tablet produces a peak in the tens of nanograms per milliliter — hundreds of times the physiological signal, sustained for hours past when the body would have cleared it.
And it does things outside the clock that have their own literature. Melatonin is a direct free radical scavenger, binds calmodulin, modulates immune cell function and is present in the gut in quantities exceeding the pineal output. Those are real and they are not what a sleep dose is being taken for Givler 2023.
Cell, rodent, human — and where it stops
The marker here is sleep onset latency measured in minutes, it moves reliably and by a small amount, and the thing people buy it for — a night's sleep — is a different quantity.
The clock biology transfers completely. The phase response curve was mapped in humans under controlled conditions, and dim light melatonin onset is a validated marker of circadian phase Burgess 2010. Nothing about circadian melatonin is speculative.
In primary sleep disorders the meta-analytic effect is real and modest. Pooled randomized trials show reduced sleep onset latency, modestly increased total sleep time and improved sleep quality Ferracioli-Oda 2013. The latency effect is on the order of several minutes to a quarter of an hour — genuinely better than nothing and much smaller than the expectation the category has created.
The dose-response has now been examined directly and it does not go the way the shelf does. A systematic review of randomized trials with dose-response meta-analysis, aimed specifically at optimizing the time and dose of melatonin as a sleep-promoting drug, finds timing to be the decisive variable and does not support the escalation to 5 and 10 mg products that dominate retail Cruz-Sanabria 2024.
The obstacle to transfer is that most people take it as a hypnotic and it is a chronobiotic. Taken 30 minutes before bed by somebody whose clock is already aligned, it produces a small sedative effect and no phase shift. Taken 4 to 6 hours before habitual sleep onset by somebody with delayed sleep phase, it moves the clock, which is the effect worth having Burgess 2010 Palagini 2021.
Where the expert consensus lands is narrower than the market. International expert recommendations position melatonin for insomnia and circadian sleep disturbance in adult neuropsychiatric disorders with attention to dose and timing rather than as a general sleep aid Palagini 2021, and the pediatric literature is explicit that indications, multisystem effects and toxicity all need stating Shenoy 2024.
Melatonin — which form, and does it matter
Immediate-release and extended-release are answering different questions and most people buy the wrong one. Immediate release produces a sharp peak that helps sleep ONSET and is gone by the middle of the night. Extended release maintains a concentration through the night and is aimed at sleep MAINTENANCE. Somebody who falls asleep fine and wakes at three is buying the wrong product almost every time.
The dose on the shelf is not the dose in the literature. Phase-shifting work uses 0.5 mg and the dose-response analysis does not support escalation Burgess 2010 Cruz-Sanabria 2024. Retail products commonly supply 5 or 10 mg, which is ten to twenty times the studied dose and produces concentrations far outside the physiological range.
The pharmacokinetics explain why a large dose backfires. Oral melatonin is absorbed rapidly, peaking at 30 to 60 minutes, and is subject to extensive and highly variable first-pass metabolism: oral bioavailability ranges from about 3 to 33 percent between individuals. Clearance is by hepatic 6-hydroxylation, overwhelmingly through the cytochrome CYP1A2 with a minor CYP2C19 contribution, followed by sulfation and renal clearance of 6-sulfatoxymelatonin. The plasma half-life is short, roughly 40 to 60 minutes for immediate release.
That one enzyme is the reason for enormous between-person variation. CYP1A2 activity varies severalfold; smoking induces it, fluvoxamine and oral contraceptives inhibit it, and caffeine competes for it. The same 3 mg dose can produce a fivefold difference in exposure between two people, which is why one person feels nothing and another wakes groggy Givler 2023.
Content against label is a documented problem in this category. Independent analyses of retail melatonin have found actual content ranging from a small fraction to several times the declared amount, with serotonin detected in some products. That variability matters most in the group with the least margin, and the pediatric review addresses exactly that Shenoy 2024.
What would have to be true, and how you would know it was not
1. Predict a small reduction in sleep onset latency and predict you can measure it. Predict sleep onset latency falls by minutes rather than by half an hour, and predict total sleep time barely changes Ferracioli-Oda 2013. Use actigraphy or a sleep diary for two weeks on and two weeks off rather than an impression.
2. Predict timing beats dose, and test it that way. Predict 0.5 mg taken 4 to 6 hours before habitual sleep onset produces a larger phase advance than 5 mg taken at bedtime Burgess 2010 Cruz-Sanabria 2024. That is a two-week self-experiment with a clear prediction and almost nobody runs it.
3. The prediction that cuts against the product. Predict that raising the dose from 1 mg to 10 mg does not produce a proportionally larger effect and does increase next-day grogginess, because the dose-response analysis does not support escalation Cruz-Sanabria 2024. A well-powered trial showing a clean dose-response through 10 mg would falsify this page.
4. Predict the circadian marker, if you want the real answer. Dim light melatonin onset, measured in saliva, is the marker that says where the clock actually is, and 6-sulfatoxymelatonin in urine reports the previous night's output. Predict that somebody who benefits most has a delayed dim light melatonin onset at baseline Palagini 2021.
5. Predict an interaction you can feel through one enzyme. Predict that a person on fluvoxamine or an oral contraceptive gets a much larger and longer melatonin effect from the same dose, and that a smoker gets less, because CYP1A2 is doing the clearing Givler 2023.
What nobody has tested yet
The right dose has never been established for the commonest use. The dose-response work points toward low doses and correct timing Cruz-Sanabria 2024, and no trial has directly compared 0.3 mg, 1 mg and 5 mg for chronic insomnia with objective sleep endpoints. The market settled on doses the literature does not support.
Long-term safety data in adults are thin. Most trials run weeks. A hormone taken nightly for years is a different exposure, and the review of chronic administration is explicit that the physiological and clinical considerations are unresolved rather than settled Givler 2023.
The pediatric question is the most consequential open one. Melatonin use in children has grown enormously, the review of indications and multisystem effects raises puberty timing and other endocrine questions, and no long-term follow-up study exists Shenoy 2024. That is the gap most worth naming on this page.
And receptor desensitization has never been characterized in people. MT1 and MT2 desensitize with sustained agonist exposure in cell systems, which predicts tolerance to nightly high doses. No human study has tested it, so the common report that melatonin stops working has a plausible mechanism and no evidence either way.
Melatonin — its own safety story, not its category's
Short-term tolerability is good and the common effects are predictable from the pharmacology. Next-morning grogginess, headache, dizziness and unusually vivid dreams, all dose-related and all more likely at 5 to 10 mg than at 0.5 to 1 mg Ferracioli-Oda 2013.
The interaction that matters most is with anticoagulation. Melatonin has been reported to potentiate warfarin, and it has mild antiplatelet activity of its own. Anyone on an anticoagulant should expect to recheck the international normalized ratio rather than assume a hormone sold in a supermarket cannot interact.
Two more pharmacological interactions worth naming. Fluvoxamine inhibits CYP1A2 strongly enough to raise melatonin exposure several-fold. And melatonin may reduce insulin secretion through MT2 receptors on the beta cell, which matters most in people with type 2 diabetes taking it at a time close to eating Givler 2023.
The pediatric situation is the one that needs stating plainly. Pediatric ingestions reported to poison centers have risen sharply alongside the growth of gummy products, and the clinical review addresses indications, multisystem effects and toxicity together for a reason Shenoy 2024. Melatonin for a child is a clinical decision, and gummies are a storage hazard.
Who should be careful. Anyone on an anticoagulant or immunosuppressant; anyone with an autoimmune condition, given the immune effects; anyone who drives early in the morning after an extended-release dose; and anyone pregnant or breastfeeding, where there are no data. And anyone taking it at bedtime for a problem that is actually a delayed clock, who is using the right molecule at the wrong hour Palagini 2021. Nothing here is medical advice or diagnosis, and these statements have not been evaluated by the Food and Drug Administration.
Sources read for this page
- Cruz-Sanabria F. Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis. J Pineal Res 2024 · PMID 38888087
- Burgess HJ, Revell VL, Molina TA, Eastman CI. Human phase response curves to three days of daily melatonin: 0.5 mg versus 3.0 mg. Journal of Clinical Endocrinology and Metabolism 2010 · PMID 20410229
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One 2013 · PMID 23691095
- Givler D. Chronic Administration of Melatonin: Physiological and Clinical Considerations. Neurol Int 2023 · PMID 36976674
- Shenoy P. Melatonin Use in Pediatrics: A Clinical Review on Indications, Multisystem Effects, and Toxicity. Children (Basel) 2024 · PMID 38539358
- Palagini L. International Expert Opinions and Recommendations on the Use of Melatonin in the Treatment of Insomnia and Circadian Sleep Disturbances in Adult Neuropsychiatric Disorders. Front Psychiatry 2021 · PMID 34177671
How you would know if it worked
There is no blood test for this one. That is not a criticism — it is a fact about the effect, and it changes how you should judge it.
- What to watch: Not the depth of the night — the timing of it. Note the clock time you first feel genuinely sleepy, to the nearest fifteen minutes, for a week before and a week after. Melatonin moves that moment earlier. It does not make the night longer or deeper, and grading it on how rested you are is grading the wrong thing.
- How long before it means anything: Three or four nights at the same clock time, because you are nudging a rhythm rather than sedating a night. Taken at the same hour each evening the phase shift accumulates; taken at a wandering hour it never gets started, and a dose whose timing drifts is not a trial of anything.
- What will fool you: The dose. Above about 3 mg most people get a morning hangover, and that grogginess reads as proof it worked when it is the sign the dose is wrong. The other one is light: a bright phone screen at midnight cancels the signal you just swallowed, so a null result may be your evening rather than the hormone.
Run it one variable at a time. Starting three things in one week means a result you cannot attribute, which is the same as no result.
Melatonin — safety & side effects
- Morning grogginess is the commonest complaint and almost always means the dose is too high. Physiological doses are 0.3–1 mg; most products sell 3–10 mg. Vivid dreams and headache are also dose-related.
- Independent assays have repeatedly found melatonin products containing anywhere from 17% to 478% of the labeled dose, and some containing serotonin. Buy from a vendor that tests.
- Interacts with warfarin, immunosuppressants, diabetes medication and fluvoxamine (which dramatically raises melatonin levels). Additive with sedatives.
- Timing matters more than dose — taken at the wrong hour it shifts your rhythm the wrong way. Caution with autoimmune disease.
Not medical advice. If you take prescription medication or have a diagnosed condition, check this against it with a pharmacist or doctor — pharmacists are underused and free.
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The full Supplement Vault — 371 products across 14 categories with clinical, correlative & theoretical evidence, plus my Thorne partner links — lives inside Skool alongside 278 peptides.
Join Skool — $10/mo →Bloodwork to run alongside Melatonin
Baseline first, then again at 8–12 weeks.
| Marker | What it’s watching for |
|---|---|
| TSH (Thyroid-Stimulating Hormone) | Thyroid disease disrupts sleep in both directions |
| Ferritin | Low iron drives restless legs, a common hidden cause |
| Vitamin D (25-Hydroxy) | Associated with sleep quality and commonly low |
| Magnesium, RBC | The form worth measuring if you're dosing magnesium |
The Sleep Quality & Recovery panel covers these in one order — 11 markers, $172.35 with the discount applied.
Check results you already have → · All 103 markers A–Z
Melatonin — frequently asked questions
What is Melatonin?
The body's darkness/sleep-timing hormone. Best understood as a circadian signal — not a sedative.
What is the suggested dose of Melatonin?
0.5–3 mg 30–60 min before bed; use the lowest effective dose. This is a general reference for education only — statements have not been evaluated by the FDA and this is not medical advice.
What are the researched benefits of Melatonin?
Meta-analyses show it shortens time to fall asleep and helps reset circadian rhythm (jet lag, shift work, delayed sleep phase).
Who is Melatonin for?
Jet lag, shift work, delayed sleep timing, and older adults with low output.
Where can I buy Melatonin?
Coach Cam sources Melatonin from Thorne, with 10% off auto-applied at checkout — use the buy link on this page.
Melatonin inside a finished plan
One arm of 2 Protocol Blueprints, free to read in full.
What Melatonin is used for
Melatonin appears under 2 goals in the goal router.
Related Sleep supplements
Where this goes next
Melatonin is the rhythm arm of this plan. The page above is the free breakdown of one compound; the plan it belongs to — the dosing, the order to correct things in, the week-by-week schedule and what to retest — is a lesson inside Skool.