Melatonin: Dosage, Timing, and What Research Shows
Last reviewed: March 21, 2026, 7:02 a.m.
Melatonin is the most widely used sleep supplement in the world, yet it is also one of the most commonly misunderstood. Unlike most sleep aids, melatonin is not a sedative. It is a chronobiotic, a substance that influences the timing of the circadian clock rather than directly inducing drowsiness. Understanding this distinction is crucial for using melatonin effectively, as improper dosing and timing are the most common reasons people report that melatonin does not work for them.
The pineal gland naturally produces approximately 0.1 to 0.8 mg of melatonin per night, with secretion beginning about 2 hours before habitual bedtime in a process called dim-light melatonin onset (DLMO). Most commercial melatonin supplements contain doses ranging from 1 to 10 mg, which can produce blood levels 3 to 60 times higher than physiological levels. Research increasingly suggests that lower doses (0.3 to 1 mg) may be more effective than high doses for sleep onset, as supraphysiological levels can actually desensitize melatonin receptors and cause next-day grogginess. A 2001 study by Zhdanova et al. in Clinical Pharmacology and Therapeutics found that 0.3 mg was as effective as 3 mg for improving sleep onset in adults.
Timing is arguably more important than dose. For difficulty falling asleep at your desired bedtime, take melatonin 30 to 60 minutes before your target sleep time. For circadian rhythm disorders such as delayed sleep phase syndrome, earlier administration (4 to 6 hours before desired bedtime) may help gradually shift the circadian clock earlier. For eastbound jet lag, take melatonin at the bedtime of your destination time zone, starting the day of travel. For westbound jet lag, melatonin in the second half of the night at the destination may help, though evidence is less clear.
Meta-analyses of melatonin for primary insomnia show consistent but modest effects. A 2013 Cochrane-level meta-analysis of 19 studies found that melatonin reduced sleep onset latency by an average of 7 minutes, increased total sleep time by 8 minutes, and improved overall sleep quality. While these numbers may seem small, the clinical significance lies in helping reset the sleep-wake cycle, which can produce cumulative benefits over time. Melatonin shows its strongest effects for jet lag (NNT of 2, meaning every other person benefits) and circadian rhythm disorders.
Safety data for melatonin is generally reassuring for short to medium-term use. Common side effects include next-morning grogginess (especially with higher doses), vivid dreams, and mild headache. Melatonin may interact with blood thinners, diabetes medications, and immunosuppressants. Quality control is a concern, as a 2017 study in the Journal of Clinical Sleep Medicine found that the actual melatonin content of supplements varied from 83% less to 478% more than the labeled dose, and 26% of products contained serotonin, an unlabeled contaminant. Choosing USP-verified or third-party-tested products is therefore particularly important for melatonin.
The pineal gland naturally produces approximately 0.1 to 0.8 mg of melatonin per night, with secretion beginning about 2 hours before habitual bedtime in a process called dim-light melatonin onset (DLMO). Most commercial melatonin supplements contain doses ranging from 1 to 10 mg, which can produce blood levels 3 to 60 times higher than physiological levels. Research increasingly suggests that lower doses (0.3 to 1 mg) may be more effective than high doses for sleep onset, as supraphysiological levels can actually desensitize melatonin receptors and cause next-day grogginess. A 2001 study by Zhdanova et al. in Clinical Pharmacology and Therapeutics found that 0.3 mg was as effective as 3 mg for improving sleep onset in adults.
Timing is arguably more important than dose. For difficulty falling asleep at your desired bedtime, take melatonin 30 to 60 minutes before your target sleep time. For circadian rhythm disorders such as delayed sleep phase syndrome, earlier administration (4 to 6 hours before desired bedtime) may help gradually shift the circadian clock earlier. For eastbound jet lag, take melatonin at the bedtime of your destination time zone, starting the day of travel. For westbound jet lag, melatonin in the second half of the night at the destination may help, though evidence is less clear.
Meta-analyses of melatonin for primary insomnia show consistent but modest effects. A 2013 Cochrane-level meta-analysis of 19 studies found that melatonin reduced sleep onset latency by an average of 7 minutes, increased total sleep time by 8 minutes, and improved overall sleep quality. While these numbers may seem small, the clinical significance lies in helping reset the sleep-wake cycle, which can produce cumulative benefits over time. Melatonin shows its strongest effects for jet lag (NNT of 2, meaning every other person benefits) and circadian rhythm disorders.
Safety data for melatonin is generally reassuring for short to medium-term use. Common side effects include next-morning grogginess (especially with higher doses), vivid dreams, and mild headache. Melatonin may interact with blood thinners, diabetes medications, and immunosuppressants. Quality control is a concern, as a 2017 study in the Journal of Clinical Sleep Medicine found that the actual melatonin content of supplements varied from 83% less to 478% more than the labeled dose, and 26% of products contained serotonin, an unlabeled contaminant. Choosing USP-verified or third-party-tested products is therefore particularly important for melatonin.