Melatonin

Melatonin is a hormone the pineal gland releases at night. It signals darkness to the rest of the body and helps set the timing of the circadian clock, distinct from directly sedating the brain the way a sleeping pill does.

The clearest evidence for melatonin is in circadian-timing problems, not ordinary insomnia. A 2002 Cochrane review by Herxheimer and Petrie pooled 10 randomized, placebo-controlled trials of oral melatonin in jet lag (975 travelers). Eight of the ten trials found melatonin, taken near the target bedtime at the destination, reduced jet lag after flights crossing five or more time zones; doses of 0.5-5 mg performed similarly, with 5 mg producing somewhat faster sleep onset than 0.5 mg, and doses above 5 mg showed no added benefit [1]. For general sleep problems, a widely cited meta-analysis of 19 studies (1,683 subjects) found melatonin reduced sleep onset latency by a modest 7.06 minutes (95% CI 4.37-9.75, p<0.001) and increased total sleep time by 8.25 minutes (95% CI 1.74-14.75, p=0.013), with a small effect on overall sleep quality (standardized mean difference 0.22) [2]. These are real, statistically significant effects, and also small ones, well short of what people expect from a "sleep supplement."

What the evidence does not show: that melatonin meaningfully treats primary insomnia the way marketing implies. Andrew Herxheimer, the same researcher behind the Cochrane jet lag review, wrote in a 2006 BMJ editorial responding to a fresh meta-analysis of melatonin in secondary sleep disorders that the trials found no significant effect on time to fall asleep and only a small, clinically unimportant increase in sleep efficiency; he called melatonin "a misapplied but probably safe" product, sold as a general sleep aid despite the evidence supporting a much narrower circadian use case [3]. Separately, a 2023 JAMA analysis by Cohen and colleagues at Harvard Medical School measured actual melatonin content in 25 US melatonin gummy products against their labels. Twenty-two of 25 (88%) were inaccurately labeled; measured content ranged from 74% to 347% of the labeled dose, one product contained no detectable melatonin at all (only cannabidiol), and only 3 of 25 products fell within 10% of label claim [4]. A consumer buying a "3 mg" gummy has no reliable way of knowing whether they are taking 2 mg or 10 mg.

No confirmed Blueprint page lists a specific melatonin protocol with a verified dose at the time of this review, so no self-experimentation claim from that program is attributed here.

Herxheimer's critique, made from inside the Cochrane review process itself, is the most direct published statement that melatonin's real, demonstrated use (circadian phase-shifting in jet lag and shift work) has been stretched by marketing into a general insomnia cure the trial evidence does not support [3].

The honest takeaway: melatonin has real, modest evidence for jet lag and circadian misalignment, and much weaker evidence for ordinary sleeplessness, and in the US the dose in the bottle in your hand is a poor guide to the dose actually inside it.

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