Melatonin

What It Does

Melatonin acts on MT1 receptors, which quiet the circadian pacemaker in the evening, and MT2 receptors, which shift its phase. Dim light melatonin onset (DLMO), when evening secretion begins, usually falls two to three hours before habitual sleep. Taken in the afternoon or early evening, before DLMO, melatonin moves the clock earlier; taken in the morning it moves it later.

Dose matters less than people assume. In older adults with insomnia and low nighttime melatonin, 0.3 mg restored sleep efficiency, while 3 mg produced daytime melatonin elevation and lowered body temperature (Zhdanova 2001). For shifting the clock, 0.5 mg produced a phase advance similar to 3 mg, and the largest shifts came when it was taken two to four hours before DLMO (Burgess 2010).

As a sleeping pill it is weak. A meta-analysis of 19 trials found melatonin shortened time to fall asleep by about 7 minutes and lengthened total sleep by about 8 (Ferracioli-Oda 2013). The American Academy of Sleep Medicine suggests against it for chronic insomnia (Sateia 2017). The better indications are circadian: jet lag after eastward travel across five or more time zones (Herxheimer 2002), delayed sleep-wake phase disorder, shift work, and non-24-hour rhythm in blind people.

Product quality is a documented problem. Among 31 Canadian products, melatonin content ranged from 83% below to 478% above the label, and some contained serotonin (Erland 2017). Of 25 US gummy products, most were mislabeled, with content from 74% to 347% of the stated amount (Cohen 2023). Pediatric melatonin ingestions reported to poison centers rose 530% between 2012 and 2021 (Lelak 2022).

Forms and Bioavailability

Absorption ratings are broad tiers. Head-to-head human trials rarely support a finer ranking among well-absorbed forms.

Immediate-release melatonin peaks within about an hour and has a half-life under an hour. It suits sleep-onset problems and clock-shifting, where a sharp signal at the right time is the point. Extended-release products spread the dose over several hours to mimic the nighttime profile; a prescription prolonged-release 2 mg tablet is licensed in Europe for insomnia in adults 55 and older. Gummies, liquids, and sprays cannot be extended release, whatever the label implies.

Typical Dosing

Doses of 0.5-5 mg are typical. Low doses (0.5 mg) are sufficient for shifting the circadian clock, where timing relative to dim light melatonin onset matters more than dose.

What to Look For

Choose low-dose tablets: 0.3-1 mg. Most products are sold at 3, 5, or 10 mg, and a scored tablet can be split. USP Verified melatonin products exist and are the best protection against the content variability above. Gummies have the worst accuracy record.

Timing beats dose. To fall asleep earlier, take 0.5 mg three to five hours before your current bedtime and keep evening light dim. For sleep onset, take it 30-60 minutes before bed. Next-day grogginess means the dose is too high.

Red flags: products combined with CBD, herbs, or other sedatives; doses of 10 mg marketed for "deep sleep"; and any melatonin stored where children can reach it.

Products on Titrate

2,685 of the 214,745 labels in the NIH Dietary Supplement Label Database list melatonin as an active ingredient (1,519 on market). 1,700 are sold as melatonin products by name.

Top on-market labels, ranked by label completeness and simplicity:

1. Melatonin 3 mg ProCaps · 3 mg
2. Melatonin 3 mg Nature Made · 3 mg
3. Melatonin 3 mg Nature Made · 3 mg
4. Melatonin 3 mg Nature Made · 3 mg
5. Melatonin 3 mg Nature Made · 3 mg

Open supplement search

Melatonin does not have its own search category yet. Each product above links to its full label in the NIH database.

Related Tools

• Melatonin Timing
• Sleep Debt Tracker
• Extended-Release Melatonin vs Immediate-Release Melatonin
• All melatonin form comparisons
• All supplement guides

References

NIH National Center for Complementary and Integrative Health. Melatonin: What You Need To Know.

Zhdanova IV, et al. Melatonin treatment for age-related insomnia. J Clin Endocrinol Metab. 2001;86(10):4727-4730.

Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520.

Burgess HJ, et al. Human phase response curves to three days of daily melatonin: 0.5 mg versus 3.0 mg. J Clin Endocrinol Metab. 2010;95(7):3325-3331.

Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773.

Erland LAE, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med. 2017;13(2):275-281.

Sateia MJ, et al. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline. J Clin Sleep Med. 2017;13(2):307-349.

Lelak K, et al. Pediatric Melatonin Ingestions: United States, 2012-2021. MMWR Morb Mortal Wkly Rep. 2022;71(22):725-729.

Cohen PA, et al. Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US. JAMA. 2023;329(16):1401-1402.