🌿 Melatonin Circadian Phase-Shift Dosing & Timing Simulator

Choose Your Circadian Scenario

Select eastward jet lag, westward jet lag, or delayed sleep phase.

• 3: Scenarios supported (east, west, delayed phase)
• ~1h/zone: Eastward shift (phase advance needed)
• ~1.5h/zone: Westward shift (phase delay needed)
• ~10%: DSPS prevalence (teens & young adults)

Eastward jet lag

Flying east makes your body clock run too late.

Westward jet lag

Flying west makes your body clock run too early.

Delayed sleep phase

Chronic late sleep onset resists earlier bedtimes.

Picking the wrong scenario can reverse the shift direction.

Current Sleep Phase vs Target Schedule

The clock face marks how far you are from your target.

• 2: Mismatch drivers (direction, zones crossed)
• hours: DSPS mismatch unit (self-reported delay)
• ~1h/day: Natural re-entrainment (without melatonin)
• major factor: Light exposure (can confound dosing)

Reading the clock

The rose marker shows your current sleep phase.

Target marker

The emerald marker shows the destination schedule.

Severity slider

A bigger mismatch needs a stronger protocol.

Larger time-zone gaps demand longer realignment windows.

Dose and Timing Recommendation

The tool computes a dose and an administration time.

• 0.5–3mg: Eastward dose range (early evening, low dose)
• 2–5mg: Westward dose range (higher dose, at bedtime)
• 0.3–1mg: DSPS dose range (afternoon microdose)
• 2: Formula inputs (scenario, severity)

Low-dose logic

Smaller doses shift phase without oversedation.

Timing window

Hours-before-bedtime placement matters more than dose size.

Pill marker

The gold pill marks the calculated clock time.

Timing errors can shift the clock the wrong direction.

Administration at the Calculated Time

Melatonin is taken at the recommended clock position.

• ~20–30min: Absorption onset (oral tablet)
• ~1h: Peak plasma level (fast-release form)
• 40–60min: Half-life (short-acting)
• MT1 / MT2: Receptor targets (suprachiasmatic nucleus)

Oral uptake

The dose enters circulation within minutes.

SCN signaling

Melatonin binds receptors that reset phase.

Consistency

The same clock time nightly speeds realignment.

Bright light near dosing time can blunt the shift.

Sleep Timing Shifts Toward Target

The current-phase marker rotates toward target over days.

• ~1 zone/day: Eastward realignment (gradual advance)
• ~1.5 zones/day: Westward realignment (faster delay shift)
• days–weeks: DSPS realignment (severity dependent)
• marker overlap: Full entrainment (current meets target)

Daily rotation

Each simulated day nudges the marker closer.

Convergence

Full realignment means the markers overlap exactly.

Maintenance

Keep timing consistent after reaching target.

Stopping early lets the clock drift back.