Melatonin timing calculator
For circadian phase shifting, Lewy and colleagues emphasize timing relative to your internal dim-light melatonin onset (DLMO). We approximate DLMO ~2 h before habitual sleep onset, then show the classic 2–6 h before DLMO exogenous window. Hypnotic “knock-out” use closer to bed is a different clinical decision — we note both below.
Estimated DLMO (rough)
20:30
~2 h before your target onset (22:30).
Phase-response style window
Consider low-dose melatonin between 14:30 and 18:30
That is 6–2 h before the estimated DLMO — the range often discussed in phase-advance/delay protocols, not a universal sleep-onset prescription.
Closer-to-bed hypnotic timing (common practice)
Many clinicians suggest taking melatonin ~30–90 min before desired sleep when the goal is sleep initiation rather than shifting phase — here ~ 21:00 for a 90-minute lead on 22:30. Discuss with a clinician if you use other sedatives or blood thinners.
Dose
Physiologic nighttime melatonin peaks near 0.3–0.5 mg in many adults. Retail gummies often ship 3–10 mg — far above the endogenous pulse — which can desensitize receptors or cause hangover for some people. Start low; prescription products may differ.
Educational estimates only. Sleep and caffeine metabolism vary widely. This is not medical advice; talk to a clinician if you have insomnia, apnea, or other conditions.