Melatonin Dosage Calculator

What is Melatonin?

Melatonin (N-acetyl-5-methoxytryptamine) is a neurohormone synthesised from serotonin in the pineal gland in response to darkness, with secretion peaking between 2–4 AM and suppressed by blue light (460–480 nm wavelengths). Its primary physiological role is not sedation but circadian phase signalling — melatonin tells the brain "it is night," shifting the timing of the sleep-wake cycle. This distinction is critical for understanding dosing: melatonin does not make you sleep deeply, it shifts when you become sleepy. At physiological nighttime levels, blood melatonin reaches approximately 80–120 pg/mL (equivalent to ~0.3 mg oral dose). Standard OTC products in North America (3–10 mg) produce blood levels 10–100× above physiological concentrations. Meta-analyses confirm efficacy for circadian rhythm disorders (jet lag, shift work, delayed sleep phase) and modest benefit for sleep-onset latency reduction (~7 minutes) in healthy adults.

How to Take Melatonin

The most important dosing principle: start dramatically lower than typical OTC products suggest. A 2001 seminal study by Dollins et al. showed that 0.3 mg of melatonin was equally effective at advancing sleep phase as 1.0 mg and 10 mg — with far fewer next-day residual effects. **Recommended doses:** Sleep-onset difficulty: 0.5–1 mg, taken 30–60 minutes before target bedtime. Jet lag (eastward travel): 0.5–3 mg at destination bedtime for 3–5 nights. Jet lag (westward travel): 0.5 mg at destination bedtime. Shift work: 1–3 mg after the last shift of a sequence, at intended sleep time. Circadian rhythm disorders (DSPD): 0.5–1 mg taken 5–6 hours before habitual sleep onset, under chronobiological guidance.

Timing Recommendations

For sleep-onset use: take 30–60 minutes before intended sleep time. The onset of sleepiness typically follows within 20–45 minutes. Do not take melatonin earlier than 2 hours before bed, as premature phase shifting may paradoxically disrupt the following night's sleep. Absolutely avoid bright light (especially blue light from screens) after taking melatonin — light directly suppresses endogenous melatonin and negates the supplement. Using blue-light-blocking glasses from 1 hour before bed + melatonin 30 minutes before bed is the most effective combined protocol.

Potential Side Effects & Safety

Next-day grogginess and cognitive dulling are the most common side effects, occurring primarily at doses ≥ 3 mg. These reflect excessive melatonin receptor occupancy extending into morning hours. Headache, dizziness, and nausea are reported at higher doses. In children, high-dose melatonin (> 3 mg) may suppress the HPG axis and interfere with pubertal development with extended use — only paediatric-specific doses (0.5–1 mg) should be used in children, under physician guidance. Tolerance to melatonin's chronobiotic effect has not been demonstrated; it does not lose efficacy with nightly use.

Best Stacks with Melatonin

Melatonin + magnesium glycinate (200–400 mg) + L-theanine (200 mg) is a non-habit-forming, evidence-aligned sleep stack addressing circadian phase (melatonin), NMDA signalling (magnesium), and GABAergic calm (L-theanine). Avoid combining with alcohol or benzodiazepines.

Scientific References

All dosage recommendations are grounded in peer-reviewed research.

1. 1
   Dose-response relationship for melatonin as a chronobiotic as well as back-extrapolation of the threshold dose

   Journal of Biological Rhythms · 2014

2. 2
   Meta-analysis: melatonin for the treatment of primary sleep disorders

   PLOS ONE · 2013