Find your optimal melatonin dose and timing. Evidence-based recommendations by age and purpose. Most people take too much — the physiological dose is smaller than you think.
Melatonin is not a sedative. It is a darkness signal — a hormone secreted by the pineal gland that communicates "night has arrived" to every cell in your body. Natural melatonin production begins at dim light melatonin onset (DLMO), roughly 2 hours before your habitual bedtime, and is suppressed almost immediately by light exposure. Peak blood levels during a normal night are only 10–100 pg/mL — far lower than the concentrations produced by a standard 5 mg supplement.
The phase response curve (PRC) is the key to timing melatonin correctly. The PRC describes how melatonin shifts your circadian clock depending on when it is taken. Doses taken in the afternoon and early evening produce phase advances (shifting sleep earlier), while doses taken after peak melatonin in the middle of the night produce phase delays (pushing sleep later). This is why timing precision matters more than dose size.
Ferracioli-Oda et al. (2013) meta-analyzed 19 randomized controlled trials and found melatonin significantly reduced sleep onset latency at doses from 0.1 mg upward. Critically, there was no dose-response relationship above 0.5 mg — higher doses produced no additional benefit but increased next-day sedation. The Auger et al. (2015) AASM clinical practice guideline recommends melatonin specifically for circadian rhythm sleep-wake disorders including delayed sleep-wake phase disorder (DSWPD), jet lag disorder, and shift work disorder.
| Age group | Recommended dose | Maximum dose | Timing |
|---|---|---|---|
| Child (4–12) | 0.5 mg | 1 mg | 30 min before bed |
| Teen (13–17) | 0.5–1 mg | 3 mg | 30–60 min before bed |
| Adult (18–65) | 0.5 mg (start) | 5 mg | 30–60 min before bed |
| Older adult (65+) | 0.5 mg | 2 mg | 30 min before bed |
Less than you think. The research-backed physiological dose is 0.3–0.5 mg — the amount that raises blood melatonin to the level your brain naturally produces. Despite what supplement labels suggest, most over-the-counter products contain 5–10 mg, which is 10–20x higher than the physiological threshold.
Ferracioli-Oda et al. (2013) conducted a meta-analysis of 19 randomized controlled trials and found that melatonin at doses as low as 0.1–0.5 mg significantly reduced sleep onset latency and improved sleep quality. Higher doses did not produce better results and were associated with morning grogginess and rebound insomnia. Start at 0.5 mg and only increase if there is no effect after 2 weeks.
Timing depends entirely on your purpose. For general sleep onset, take melatonin 30–60 minutes before your target bedtime. This corresponds to the rising phase of your natural melatonin rhythm, amplifying the signal your brain is already sending.
For jet lag (eastward travel), take melatonin at the destination bedtime starting on day 1 of travel, for 2–5 days. For westward travel, a morning dose at the destination can help advance your clock more gently. For circadian phase shifting (e.g., shift workers), timing 5–7 hours before your desired sleep time exploits the phase response curve's advance zone, which is more powerful than the standard pre-bed window.
Short-term melatonin use (up to 3 months) is considered safe for most healthy adults. It is not habit-forming and does not suppress the body's own melatonin production the way sedatives affect GABA receptors. However, long-term safety data beyond 6 months is limited, and melatonin is classified as a dietary supplement (not a drug) in the United States, which means quality control varies widely between brands.
The Auger et al. (2015) AASM guideline recommends melatonin for circadian rhythm disorders (DSPD, jet lag, shift work disorder) but notes that evidence for primary insomnia is weaker. Groups requiring caution include: pregnant or breastfeeding women, people on blood thinners (warfarin), immunosuppressants, or diabetes medications, and children under 4. Always consult a physician if you take any of these medications or have an underlying condition.
Yes. While melatonin is not acutely toxic in overdose the way many sedatives are, taking too much causes real, measurable problems. High doses (5–10 mg or more) can cause next-day grogginess, headache, dizziness, and nausea. More importantly, pharmacological doses can desensitize melatonin receptors over time, making your brain less responsive to both supplemental and natural melatonin.
A single large dose can also shift your circadian phase in the wrong direction if timed incorrectly — acting as a pro-waking signal rather than a sleep signal. The "more is better" assumption is particularly harmful here. Research consistently shows that 0.5 mg is as effective as 5 mg for reducing sleep onset latency, with far fewer side effects. If you have been taking high doses and feel they stopped working, that unresponsiveness may itself be a consequence of receptor downregulation.
Dosing recommendations from the research literature and AASM guidelines differ substantially by age group:
Children (4–12): 0.5–1 mg maximum, at least 30 minutes before bedtime. Melatonin for children should only be used under pediatric supervision. The AASM recommends it specifically for autism spectrum disorder-related sleep onset difficulties, not for typical childhood sleep issues. Dose should be the lowest effective amount.
Teens (13–17): 0.5–3 mg. Adolescent circadian rhythms naturally shift later (delayed phase), so melatonin is most useful for advancing sleep timing, not just inducing sedation. Low doses (0.5–1 mg) taken 5–6 hours before desired sleep onset are more effective than high pre-bed doses.
Adults (18–65): Start at 0.5 mg. Increase to 1–3 mg if needed. The 5 mg threshold is rarely necessary and mostly found in commercial products for marketing reasons.
Older adults (65+): 0.5–2 mg. Melatonin production naturally declines with age, making supplementation more meaningful. However, older adults are more sensitive to sedative effects and drug interactions — start with 0.5 mg.
Yes — jet lag is the best-supported use case for melatonin. Auger et al. (2015) and multiple Cochrane reviews confirm that melatonin significantly reduces jet lag symptoms, particularly for eastward travel crossing 5 or more time zones. The mechanism is direct: melatonin shifts your circadian clock's phase by acting on MT1/MT2 receptors in the suprachiasmatic nucleus (SCN), the brain's master clock.
The critical variable is timing. For eastward travel, take 0.5–3 mg at the destination bedtime (not your home bedtime) for 2–5 nights. For westward travel, the clock shifts more easily in that direction naturally, and morning light exposure is often sufficient — but a low dose taken in the morning at the destination can accelerate adaptation. Avoid taking melatonin in the middle of the day in your home time zone, as this can worsen jet lag by shifting your clock in the wrong direction.