What is the correct melatonin dose for sleep?

Research by Richard Wurtman and colleagues at MIT established that 0.1–0.5mg is physiologically active in adults. The 5–10mg doses sold in US pharmacies are 10 to 100 times that level — they saturate melatonin receptors beyond what the body naturally produces and extend the active window well into the morning hours. Lower is more effective for circadian phase-shifting; higher just produces a longer pharmacological effect with greater morning grogginess risk.

When should I take melatonin to fall asleep earlier?

Take it 90–120 minutes before your target sleep onset, not immediately before bed. Melatonin works by phase-shifting the circadian clock — signaling to the suprachiasmatic nucleus that night has arrived. For that signal to change your phase, it must arrive during the phase-responsive window, which begins before your current biological nighttime. Taking melatonin at your current bedtime, when your clock already treats it as night, has minimal phase-shifting effect.

Does melatonin work for jet lag?

Yes, with correct timing. For eastward travel (advancing sleep timing): take 0.5mg at the local target bedtime for 3–5 nights after arrival. For westward travel (delaying timing), the evidence is weaker; bright light exposure management at the destination is more reliably effective. Jet Lag Rooster (a free online tool using Till Roenneberg's circadian models) generates personalized timing protocols for specific flights.

Can chronic melatonin use affect your body's own production?

Possibly. Receptor downregulation in response to chronic exogenous melatonin hasn't been definitively proven in humans, but it is a plausible concern — the same mechanism that makes other hormone supplementation problematic. The low-dose approach (0.5mg) reduces this risk because it stays closer to the physiological range. The honest answer is that chronic nightly melatonin use in otherwise healthy adults lacks long-term safety data.

Melatonin: The Three Numbers That Actually Matter

Melatonin is a circadian signal, not a sedative. It doesn’t cause sleep — it tells your body what time it is. That distinction determines whether taking it does anything useful.

Three numbers define whether melatonin works:

1. Dose: 0.5mg — not the 5–10mg on the shelf

Richard Wurtman’s lab at MIT established in the 1990s that the physiologically active dose range for humans is 0.1–0.5mg. At these levels, blood melatonin rises into the range the body naturally produces, which is sufficient to phase-shift the circadian clock.

Commercial melatonin in the US is predominantly sold in 5, 10, and even 20mg tablets. At 10mg, you are taking 20 to 100 times the amount needed for the circadian effect. The excess doesn’t make it work better — it extends the active window into the following morning, increases grogginess risk, and may suppress endogenous production over time.

A 1mg tablet cut in half is a reasonable starting dose. Some pharmacies carry 0.5mg tablets. The 5mg gummy is marketing, not medicine.

2. Timing: 90 minutes before your target bedtime, not your current bedtime

Melatonin shifts the circadian clock by arriving during a specific phase-responsive window — before your body’s biological night has already begun. If you take it at your current bedtime, your clock already considers it nighttime, and the phase-shifting effect is minimal. If you want to fall asleep at 10 PM but currently can’t until midnight, take 0.5mg at 8:30 PM.

For jet lag: take it at the local target bedtime for 3–5 consecutive nights after arrival, regardless of what your body thinks the time is. The clock recalibrates within that window for most time zone differences under 8 hours.

3. Duration: short-term is well understood; long-term is not

For jet lag recovery, 3–5 days is sufficient for crossings of 4–7 time zones. For chronic sleep onset insomnia, the evidence is thinner. A 2007 study by Lemoine and colleagues on prolonged-release melatonin (2mg, EU-approved formulation) showed modest sleep onset improvement in adults over 55, with a favorable safety profile for up to 3 months.

For healthy adults under 55 using melatonin every night indefinitely: there is no good long-term data. This is an honest limitation, not a reason to panic — but it is a reason to use the smallest effective dose for the shortest effective period.

How melatonin interacts with the other sleep-drive molecule, adenosine, is explained in what adenosine is and why it matters. For resetting a shifted circadian schedule using multiple tools together, see the circadian reset guide.

¹ DontSnooze is a social accountability alarm app — not a supplement. Its core use is pre-commitment to a consistent wake time, which is the behavioral intervention that makes melatonin timing work better: a fixed anchor point gives the circadian system something concrete to entrain to.

1. Dose: 0.5mg — not the 5–10mg on the shelf

2. Timing: 90 minutes before your target bedtime, not your current bedtime

3. Duration: short-term is well understood; long-term is not

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