Melatonin: timing, labels and the questions to ask

Melatonin gets its own tab in every sleep category, usually with a number on the front of the pack that sounds very sure of itself. Put two packs side by side and the numbers can be quite different, while neither says much about when to take it. That makes this a good moment to ask what melatonin actually is, which amounts and timings research and regulators talk about, and what a label can and can't tell you. We report studied and regulated amounts as exactly that, and we don't give personal doses.

The short version: melatonin is the body's darkness signal, not a sleeping pill, so when you take it matters at least as much as how much. Studies show a small average benefit for falling asleep faster, a clearer one for jet lag, and a role for carefully timed low doses in body-clock disorders. Dutch and European guidance is notably cool on using it for ordinary insomnia. Amounts in studies (often 0.5 mg to a few milligrams) differ from amounts on shop labels (0.99 mg and 1.5 mg on the two products described below), and the Netherlands has a 0.3 mg line that can tip a product into medicine territory, depending on other criteria (covered in the rules section).

The page in five lines

• Melatonin is a hormone that signals "biological night". The Dutch sleep-medicine working group describes it as the hormone of the night, not a sleep hormone, which is why taking it at the wrong time can backfire.
• For sleep onset, a 2013 meta-analysis found about 7 minutes faster on average. The European Insomnia Guideline 2023 does not recommend fast-release melatonin for insomnia. Evidence is better for jet lag and for body-clock timing problems.
• Studied amounts range from 0.5 mg to 5 mg for jet lag, with similar effects across that range, while labels vary even more. Independent tests of melatonin supplements have found measured content far above or below the label.
• The Netherlands has a 0.3 mg line that can tip a product into medicine territory, depending on other criteria. In the EU, supplement limits are set country by country.
• Drowsiness, interactions (for example with fluvoxamine), pregnancy and breastfeeding, and use in children all call for professional advice, not label guesswork.

Melatonin is a timing signal, not a sleep switch

Your brain's pineal gland releases melatonin in a daily rhythm controlled by the body clock in the hypothalamus. Levels rise in the evening, in step with a drop in body temperature and alertness, and fall towards morning. The Dutch working group of sleep specialists (October 2025 expert opinion for clinicians) points out that melatonin isn't needed to sleep: daytime dozers have low melatonin, and people whose pineal gland has been removed show no change in sleep quality on polysomnography. Hence "hormone of the night, not sleep hormone". The same document puts melatonin's half-life at 20–50 minutes.

Taken as a pill, melatonin does two separate things. It acts as a timing signal that can shift the body clock earlier or later depending on when it's taken, and at higher amounts it has a mild sedating effect, with a drop in core body temperature. The working group notes that a 1–5 mg dose raises blood levels five to 200 times or more above the usual night-time peak, while 0.1–0.3 mg is enough to reach levels seen during the biological night. That gap is why "more" isn't automatically better: higher doses can stay in the body long enough to act on the clock at the wrong moment.

Timing: why the clock matters as much as the amount

The working group describes the clock-shifting effect as depending on a "phase response curve": melatonin taken in the evening shifts the clock earlier, melatonin taken in the early morning can shift it later. For people with a delayed body clock, the group's clinician guidance cites 0.5 mg taken roughly 2–4 hours before dim-light melatonin onset (the point where natural melatonin starts rising, which the working group puts at roughly two to three hours before falling asleep in adults), or about five hours before DLMO at 3 mg. That is expert guidance for clinicians treating diagnosed circadian rhythm disorders, not a schedule for self-treatment. Once a rhythm is established, the group says a dose about two hours before the desired sleep time matches the natural gap between melatonin release and sleep.

For jet lag the picture is different: a Cochrane review (Herxheimer & Petrie, 2002; ten trials) found melatonin taken near the target bedtime at the destination (10 pm to midnight) to be effective, with 0.5–5 mg similarly effective and doses above 5 mg no better. Benefit was greater the more time zones were crossed and smaller for westward flights.

So "take it before bed", the instruction on most labels, isn't necessarily the timing used in the studies for the situation you're in.

What the evidence says, situation by situation

• Situation: Falling asleep, in people with primary sleep disorders; What the evidence shows: 19 trials, 1,683 people: sleep onset about 7 minutes shorter, total sleep time about 8 minutes longer than placebo; authors call the effects modest; Source: Ferracioli-Oda and colleagues, PLoS ONE, 2013
• Situation: Chronic insomnia in adults; What the evidence shows: European guideline: CBT-I first-line; prolonged-release melatonin may be used for up to 3 months in people aged 55 and over; fast-release melatonin not recommended; Source: Riemann and colleagues, Journal of Sleep Research, 2023
• Situation: Jet lag; What the evidence shows: Effective when taken at destination bedtime; 0.5–5 mg similar; more effect with more time zones crossed; Source: Cochrane, Herxheimer & Petrie, 2002
• Situation: Delayed or irregular body-clock timing; What the evidence shows: Low doses taken at carefully chosen times are the main clinical use; Source: Dutch working group, 2025
• Situation: Shift work; What the evidence shows: Mixed. The US National Center for Complementary and Integrative Health (NCCIH) says people taking melatonin may sleep about 24 minutes longer in the daytime. The Dutch working group judges the evidence insufficient and of low quality and does not advise melatonin for irregular shifts; Source: NCCIH; Dutch working group, 2025

Two Dutch national sources are blunter than the research summary. Thuisarts, the Dutch GP information site, says melatonin doesn't effectively treat sleep problems and can make them worse, with long-distance jet lag as the exception. The Farmacotherapeutisch Kompas (Zorginstituut Nederland) states that using melatonin without a medical indication and supervision is discouraged because it has no clinically relevant effect on insomnia. Those are national clinical positions, and they read very differently from the shop shelf.

Amounts in studies versus amounts on labels

This is where most of the confusion lives, so here are the figures side by side. Each is a reported amount, not a recommendation.

• Context: Jet lag trials (Cochrane); Amount reported: 0.5–5 mg, similar effects across the range; Source: Herxheimer & Petrie, 2002
• Context: Phase-shifting, clinician-guided; Amount reported: 0.5 mg, or 3 mg with earlier timing; Source: Dutch working group, 2025
• Context: Levels similar to the natural night-time peak; Amount reported: 0.1–0.3 mg described as reaching night-time levels; 0.3–0.5 mg called physiological; Source: Dutch working group, 2025
• Context: Prolonged-release prescription medicine for adults aged 55+; Amount reported: 2 mg registered for insomnia; guideline allows up to 3 months; Source: Dutch working group; Riemann and colleagues, 2023
• Context: EU authorised health claim: sleep onset; Amount reported: 1 mg per portion, close to bedtime; Source: Regulation (EU) No 432/2012, as summarised by secondary sources
• Context: EU authorised health claim: jet lag; Amount reported: at least 0.5 mg; Source: same
• Context: Dutch regulatory line (explained in the rules section); Amount reported: 0.3 mg a day; Source: IGJ; government reply, 2019

Now compare with what two product pages said on 8 October 2026. Both are supplier information.

• Cibdol Fall Asleep (capsules and liquid): 1.5 mg melatonin per capsule or per 1 ml, with 2.5 mg CBD, per serving. The brand's Meladol page quotes the EU sleep-onset claim and says the effect is obtained with 1 mg shortly before bed. The capsule page says "intended for short-term use", advises 30 minutes before bed (a category listing says 1–2 hours), and warns about drowsiness and driving.
• Zamnesia Dream Tablets 3-in-1: 0.99 mg melatonin per tablet alongside valerian, passionflower, chamomile, lemon balm, GABA, magnesium, L-tryptophan and vitamins; instructions say 1 tablet 30–60 minutes before bed.

Both amounts are above the 0.3 mg figure IGJ uses, which is not a finding about legality: classification also depends on other criteria, and the pages don't show either product's registration status. The useful prompt is a question for the seller: which market and which category is this pack sold under?

Do the labels match the pot? Independent tests suggest the answer isn't always yes. A 2017 study of 30 Canadian supplements found measured melatonin from 83% below to 478% above the label, with lot-to-lot differences up to 465% (Erland & Saxena, Journal of Clinical Sleep Medicine). A 2023 analysis of 25 US gummies found 22 inaccurately labelled, with measured melatonin 74–347% of the label and 1.3–13.1 mg per serving (Cohen and colleagues, JAMA). In a 2025 analysis of melatonin supplements sold online in the EU, 12% of the 25 products from legal supply chains had unauthorised health claims or at least triple the melatonin allowed in Belgium (Molecules). None of these tests covered the products above. They are the reason a certificate of analysis or batch-testing statement is worth asking for.

What the rules say (checked 8 October 2026)

Netherlands. According to the Dutch government's reply to parliamentary questions (8 October 2019; Kamervragen 2019-2020, nr. 297), melatonin below 0.3 mg per dose may be marketed as a food supplement only if the pack carries no health claim at all ("geen enkele gezondheidsclaim"). A sleep-onset claim is a health claim, so a low dose alone doesn't settle which side of the line a shop pack sits on. At 0.3 mg and above, the reply says there can be a medicine ("kan er sprake zijn van een geneesmiddel") if the product also meets a number of other criteria, set by court rulings such as the EU Court of Justice's Hecht-Pharma, and it acknowledges that melatonin has long been sold as a supplement at various doses, including above 0.3 mg. IGJ's own FAQ says that from a daily dose of 0.3 mg "there is, according to current scientific data, a product with a noticeable and beneficial effect", that medicines need registration, and that consumers can check the medicines database (geneesmiddeleninformatiebank.nl). Fines replaced written warnings from 1 July 2020. In April 2026 the Council of State (ECLI:NL:RVS:2026:1846, 1 April 2026) is reported to have upheld the approach; this comes from a law firm's summary, not the judgement. Before that, the Dutch sleep working group noted in October 2025 that manufacturers' appeal was pending.

Is 5 mg allowed in the Netherlands? A 5 mg pack sits on the "0.3 mg and above" side of that line, so the dose alone can't answer it. Whether a particular pack is lawful depends on its registration and on the court criteria, which a label can't show. IGJ tells consumers to check the medicines database.

EU. There is no EU-wide supplement limit; national rules differ, and some countries treat melatonin as a medicine. Two authorised EU health claims exist (Regulation (EU) No 432/2012: sleep onset at 1 mg; jet lag at 0.5 mg), and a product can use that exact wording only if it meets the stated condition. The regulation is linked here, but those two conditions are unconfirmed against the Official Journal and come from summaries. EFSA's 2011 opinion (EFSA Journal 9:2241) is the basis for the sleep-onset claim, though we know it only from summaries.

Prolonged-release melatonin is a separate category: the working group refers to a registered 2 mg medicine for insomnia in people over 55, and the European guideline's three-month allowance applies to that kind of product. It isn't the same thing as a supplement tablet with "slow release" on the front, and the dispensing category of any particular product should be checked.

Safety: what to know before you reach for it

• Next-day drowsiness and driving. The working group says subjective sleepiness generally occurs in the first hour after taking melatonin and sometimes fades after weeks of daily use; headache and sleepiness are reported in 1–10% of users, and other side effects in under 1%. Cibdol's Fall Asleep pages advise against driving or operating machinery after taking it.
• Reported side effects. The Dutch pharmacovigilance centre Lareb received 181 reports about melatonin by February 2020, most often diarrhoea, headache, dizziness, nausea, palpitations, insomnia and unusual dreams or nightmares, and noted that side-effect information on consumer-goods products is often incomplete.
• Interactions. Melatonin is mainly broken down by the liver enzyme CYP1A2. The working group lists fluvoxamine (an antidepressant) as a major inhibitor that can raise melatonin levels about twelve-fold, and notes that smoking lowers levels, while some other drugs (including ciprofloxacin and cimetidine) and caffeine can influence them. NCCIH says people taking blood thinners need medical supervision. See our guide to supplements and medication.
• Slow metabolisers. The working group reports that 5–14% of adults break melatonin down slowly, which can make it build up and disturb sleep, with a trial stop of 3–6 weeks as one way clinicians check.
• Pregnancy and breastfeeding. NCCIH says safety research in pregnant or breastfeeding women is lacking. The working group does not recommend melatonin in pregnancy or breastfeeding, because the clinical data are inadequate. Cibdol's Fall Asleep pages also say to talk to a doctor first.
• Children. There are no child doses here. The working group describes specialist use in children, usually after sleep-habit and behavioural approaches, under professional guidance, and cites US reports that too-high doses in young children occasionally led to serious adverse events.
• Older adults. The working group cites evidence that melatonin in older adults carries a hip-fracture risk similar to benzodiazepines and says it shouldn't be regarded as a safe alternative.
• Long-term use. NCCIH says long-term safety information is lacking. The working group suggests that after about a year of daily use, clinicians should stop and reassess whether it is still needed.

Eight questions to put to a melatonin label

1. How many milligrams per serving, and what is a serving? A capsule, a millilitre, a daily dose of two tablets?
2. Is it fast-release or prolonged-release? Prolonged-release melatonin is a separate, registered-medicine category in the guidance.
3. Is the amount close to the studied range for my situation, or far above it? A label saying 5 mg isn't doing something 0.5 mg can't, according to the jet lag review, and extra can mean more drowsiness.
4. What timing does the label give, and is it for sleep onset or for body-clock shifting? They differ.
5. Does the label match the pot? Look for batch testing or a certificate of analysis, given the label-accuracy studies above.
6. What else is in it? Combination products can hide a second sedating or serotonergic ingredient.
7. Is it sold for my country, and in which regulatory category? Check the medicines database in the Netherlands, and expect different answers elsewhere in the EU.
8. What would count as success, and when would I review it? If sleep isn't better, or is worse, stopping and talking to a professional is the standard next step, not a bigger tablet.

When a GP is the better first step

If sleep problems are regular or affecting your days, the evidence-based first step is CBT-I and a conversation with a GP. The European Insomnia Guideline 2023 says that CBT-I is the first-line treatment for chronic insomnia in adults, and the NHS advises seeing a doctor when changing your sleep habits hasn't helped or insomnia is making daily life hard to cope with. Thuisarts says to book a GP appointment when the sleep advice isn't enough. Our sleep routines guide covers the non-product basics, and the label-reading guide covers general quality checks.

The number on the box, in context

Melatonin is a timing signal first and a mild sedative second, which makes "how much and when" a question that depends on why you're taking it. Studies exist for jet lag and body-clock disorders and are modest for sleep onset. Together with the Dutch regulatory position and the label-accuracy data, that makes the number on the front of the box worth reading with a little curiosity. If melatonin is one ingredient in a combination product, the same label questions apply.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 12 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.