Melatonin Half-Life & Clearance
Understand how long Melatonin stays in your bloodstream, its metabolic pathways, and how to time your doses optimally.
Standard Pharmacokinetics
Chart represents a single standard dose processed by a normal metabolizer over 24 hours.
Key Metrics
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See how Melatonin overlaps with caffeine, modafinil, and your target bedtime.
Open Interactive CalculatorMetabolism & Excretion
Pathway
Hepatic CYP1A2 (primary); first-pass metabolism very significant (97% metabolized)
Elimination
Urine (as 6-sulphatoxymelatonin)
Important Nuances
Oral melatonin bioavailability is extremely low (~3%) due to massive first-pass metabolism. Lower doses (0.5–1mg) are generally as effective as high doses (5–10mg) for circadian signaling purposes. Sublingual formulations have better bioavailability.
Frequently Asked Questions
Why isn't more melatonin always better?
Melatonin works via receptor binding for circadian signaling — the dose-response curve is not linear. 0.5mg can be as effective as 5mg for sleep onset while producing significantly less morning grogginess. The 5–10mg doses common in US supplements are pharmacological doses, not physiological ones.
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