How long does Ozempic
stay in your system?
Tell us when you took it and how much — see exactly what's left right now.
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What is the half-life of Ozempic?
Ozempic (Semaglutide) has an estimated half-life of about 7 days. The amount in your body is reduced by about half on that schedule. FDA prescribing information / Novo Nordisk: half-life of approximately 1 week
Semaglutide's roughly 7-day half-life is slightly longer than tirzepatide's (the active ingredient in Mounjaro), which is why Ozempic's effects are often described as feeling a bit more 'level' across the week. Like tirzepatide, semaglutide is engineered to bind albumin in the bloodstream, which is what slows its clearance enough to support once-weekly dosing instead of the daily injections older GLP-1 medications required.
How does this calculator work?
This tool applies the formula Remaining = Initial × 0.5^(elapsed time ÷ half-life) to the half-life value above. Enter your amount and when it was taken, and it estimates how much is mathematically remaining right now, plotted on a chart and timeline that show real clock times rather than abstract durations, so you can see, for example, that "8:35 PM" is the dose and "9:35 PM" is one hour later, not just "1 hour."
How long does Ozempic stay in the body?
Based on a 7 days half-life, it takes roughly five to seven half-lives for the mathematical model to reach a trace amount, generally under 2% of the original dose. Individual elimination varies with metabolism, dose, organ function, genetics, and other factors this calculation doesn't see.
A single dose of semaglutide takes about five half-lives, or roughly five weeks, to drop to a few percent of its starting level — which is why prescribing information advises a 'prolonged period of observation' after an overdose, and why effects don't disappear immediately after a missed or final dose. With weekly dosing, semaglutide builds toward a stable steady-state level over about 4 to 5 weeks, similar to tirzepatide but slightly slower given the longer half-life.
Frequently asked questions
Is this medical advice?
No. This is a mathematical estimate only, not medical advice. It doesn't account for individual metabolism, organ function, drug interactions, or absorption rate, and shouldn't be used for medication, dosing, driving, or health decisions. See our terms of use for the full disclaimer.
Why is this only an estimate?
Real elimination depends on age, weight, liver and kidney function, genetics, and other medications, none of which this calculator can know. It applies one published half-life value to a simple decay curve rather than a personalized pharmacokinetic model.
Why does it take weeks to feel less hungry after stopping Ozempic?
Because the half-life is about a week, a meaningful amount remains in your system for several weeks after the last dose — appetite-suppressing effects fade gradually over that window rather than stopping abruptly.
Can this tell me when Ozempic is completely gone?
Not precisely. Exponential decay approaches zero but never mathematically reaches it. After about five to seven half-lives, the remaining amount is a trace consistent with being effectively eliminated for most practical purposes.