Modafinil Half-Life & Clearance
Understand how long Modafinil 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 Modafinil overlaps with caffeine, modafinil, and your target bedtime.
Open Interactive CalculatorMetabolism & Excretion
Pathway
Hepatic amide hydrolysis, CYP3A4 (minor), CYP2C19
Elimination
Urine (majority as modafinil acid)
Important Nuances
Active R-enantiomer has slightly longer half-life (~15 hrs). Doses >200mg may have disproportionately longer effects in some individuals.
Frequently Asked Questions
What is the half-life of modafinil?
Modafinil has a half-life of approximately 12–15 hours. If you take it at 7 AM, roughly half remains active by 7–10 PM, which is why modafinil should always be taken early in the morning to avoid sleep disruption.
How long does modafinil stay in your system?
Modafinil is substantially cleared (>95%) after approximately 60–75 hours (2.5–3 days). It is detectable in urine for up to 30 hours after a single dose.
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