😴 Melatonin Circadian Timing Simulator

The Endogenous Melatonin Circadian Curve

Pineal melatonin secretion follows a robust daily rhythm gated by the suprachiasmatic nucleus.

• ~2-4am: Peak time (core body temp minimum nearby)
• ~21:00: DLMO (dim light melatonin onset)
• ~1 pg/mL: Daytime level (near baseline)
• ~50-60 pg/mL: Night peak (plasma concentration)

Endogenous rhythm basics

Placeholder: SCN drives nightly melatonin rise and daytime suppression by light.

Exogenous Dose Timing Relative to the Curve

When a dose is taken relative to DLMO determines its phase-shifting effect.

• 1-10mg: Typical OTC dose (wide commercial range)
• 0.5mg: Effective phase dose (often sufficient)
• ~30-60min: Absorption (time to peak plasma)
• ~45min: Half-life (short duration)

Timing relative to DLMO

Placeholder: earlier dosing before DLMO shifts phase more than late dosing.

Phase Advance Protocol for Delayed Sleep Phase

Low-dose melatonin several hours before target bedtime advances sleep onset.

• 0.5-1mg: Best dose (low-dose chronobiotic)
• 5-7h pre-bed: Timing window (before habitual sleep)
• days-weeks: Onset of effect (gradual entrainment)
• AM bright light: Combine with (reinforces advance)

Advancing a delayed clock

Placeholder: early low-dose melatonin plus morning light advances DSPS.

Phase Shift Strategy for Jet Lag

Melatonin timed to the destination bedtime speeds circadian re-entrainment.

• Advance: Eastward travel (take near dest. bedtime)
• Delay: Westward travel (take later, or skip)
• 0.5-5mg: Typical dose (lower often adequate)
• ~1 day/zone: Re-entrainment (without treatment)

Direction-dependent dosing

Placeholder: dosing direction depends on eastward vs westward travel.

Low-Dose Timing vs High-Dose Sedation

Low doses act as a chronobiotic; high doses mainly sedate without extra phase effect.

• 0.3-1mg: Chronobiotic range (phase-shifting sweet spot)
• >3mg: Sedative range (supraphysiological levels)
• yes: Ceiling effect (more mg ≠ more shift)
• dose-dependent: Next-day grogginess (higher dose, more residual)

Dose-response tradeoff

Placeholder: higher doses trade phase precision for sedation.