Semaglutide has a reported half-life of about 7 days.
By the five-half-lives rule, a single dose substantially clears in roughly five weeks.
Because it is dosed weekly, levels accumulate — so after the last dose it clears from a higher starting point and takes longer.
The long half-life comes from albumin binding, the same feature that allows once-weekly dosing.
These are population averages; individual clearance varies.
Semaglutide has a reported half-life of about 7 days1, so a single dose takes roughly five weeks to substantially clear — and because it is dosed weekly, accumulated levels take even longer to disappear after the final dose.
In plain terms: it leaves slowly, and regular dosing means there is extra on board to leave.
Fig. Weekly dosing accumulates: each semaglutide dose lands before the previous has cleared, so levels build toward a plateau (steady-state) over roughly five half-lives. Single-dose decay (grey) versus repeated weekly dosing (gradient). An illustrative model from the published half-life, not a measurement.
Confirmed a half-life of about 1 week, supporting once-weekly dosing
2019
In plain terms: the long half-life is not an accident — it was designed in (Lau 2015) and later confirmed in people (Overgaard 2019).
The accumulation caveat
The five-week figure is for a *single* dose. Weekly dosing accumulates toward steady-state, so at the point someone stops there is more on board than one dose — and it clears from that higher starting amount. "Out of your system" after the last dose therefore takes longer than five weeks in practice.
Why the long half-life exists
Semaglutide is engineered for a long half-life through albumin binding2, which is precisely what allows weekly dosing. The same property means a missed dose is cushioned by the slow decay.
These are population estimates. Individual clearance varies. This describes pharmacokinetics, not a personal timeline, and is not medical advice.
Frequently asked
How long until semaglutide is out of your system?
Semaglutide has a reported half-life of about 7 days, so roughly 97% of a single dose clears after about five half-lives — approximately five weeks. With repeated weekly dosing, levels accumulate and take correspondingly longer to fully clear after the last dose.
Why is semaglutide half-life so long?
It carries a fatty-acid chain that binds albumin, an abundant, long-circulating blood protein. Bound to albumin, the molecule is shielded from rapid breakdown, stretching the half-life to about a week.
Does semaglutide build up over time?
Yes. Because each weekly dose lands before the previous one clears, levels accumulate over roughly the first five weeks toward a steady plateau, then hold. After stopping, clearance begins from that accumulated level.
References
Overgaard RV, Delff PH, Petri KCC, et al. Population Pharmacokinetics of Semaglutide for Type 2 Diabetes.Diabetes Ther. 2019. DOI 10.1007/s13300-019-0581-y
Lau J, Bloch P, Schäffer L, et al. Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide.J Med Chem. 2015. DOI 10.1021/acs.jmedchem.5b01016
Rowland M, Tozer TN. Clinical Pharmacokinetics and Pharmacodynamics: Concepts and Applications (4th ed.).Lippincott Williams & Wilkins. 2011. ISBN 978-0-7817-5009-7
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