How Long Do Zepbound, Wegovy and Other GLP-1s Stay in Your System?

Tirzepatide, the drug in Zepbound and Mounjaro, has a half-life of about 5 to 6 days, so most of it is gone roughly a month after the last injection.^[1][2] Semaglutide (Wegovy, Ozempic) lasts longer: it has a week-long half-life, and Wegovy’s label says it is still in the circulation 5 to 7 weeks after a last dose.^[3] Daily liraglutide (Saxenda) is cleared within a few days.^[5] The figures below come from each FDA label, with the trial estimate for retatrutide, which is not yet approved.

Half-life and the five half-lives rule

A drug’s half-life is how long the blood level takes to drop to half of where it was. Half remains after one; a quarter after two; roughly 3% after five. That is why pharmacists use five half-lives as a working estimate of when a drug has mostly washed out. It is arithmetic, and it fits what the semaglutide labels say directly: a half-life of about a week, and, per Ozempic’s label, roughly five weeks for the last dose to leave.^[4]

The long half-lives are deliberate. Tirzepatide carries a fatty acid chain that binds it to albumin in the blood, which is how the label explains its once-weekly dosing.^[1] The same albumin binding protects semaglutide from being filtered and broken down.^[4]

How long each GLP-1 lasts

Sources for the rows: Zepbound,^[1] Mounjaro,^[2] Wegovy,^[3] Ozempic,^[4] Saxenda,^[5] Trulicity,^[6] Foundayo,^[7] Rybelsus and Ozempic tablets^[8] and retatrutide.^[9] The fourth column is the half-life multiplied by five, rounded.

How long Zepbound and Mounjaro stay in your system

About a month. For tirzepatide in people treated for weight, Zepbound’s label puts the half-life at 5 to 6 days; Mounjaro’s label, written for diabetes, says about 5.^[1][2] Five half-lives is 25 to 30 days. The label does not name a washout date for tirzepatide the way the semaglutide labels do, so the month is an estimate from the half-life rather than a figure Lilly prints. The washout calculator runs the same arithmetic from the date of your last dose.

Going the other way, levels build for about four weeks after you start or change a dose before they level off.^[1] Compounded tirzepatide, where it actually contains tirzepatide at the stated strength, is the same molecule and clears on the same timetable.

How long semaglutide stays in your system

Five to seven weeks. Semaglutide is the one drug here whose label states the washout outright, and Wegovy’s does it in a single sentence:^[3]

“With an elimination half-life of approximately 1 week, semaglutide will be present in the circulation for about 5 to 7 weeks after the last injectable dose of 2.4 mg or 7.2 mg or oral dose of 25 mg.”

— Wegovy prescribing information, section 12.3

The tablet and the injection end up in the same place. The Wegovy pill is absorbed poorly, but what does get in has the same week-long half-life, and the Rybelsus label gives the same five weeks after a last tablet.^[8]

Saxenda and Foundayo clear within days

Liraglutide’s half-life is about 13 hours, which is why Saxenda is injected every day.^[5] Five half-lives is under three days. Orforglipron, the active ingredient in Foundayo, sits in between: 29 to 49 hours, so most of it is gone within a week or so of the last tablet.^[7] For anyone who wants a drug that leaves quickly if a side effect appears, these two are the shortest-acting options, and our Foundayo explainer covers how orforglipron differs from the peptides.

Retatrutide

Retatrutide is still investigational, so there is no FDA label to quote. In its phase 1b trial in people with type 2 diabetes, the pharmacokinetics were dose-proportional and the half-life was approximately 6 days.^[9] That puts it close to tirzepatide, with most of a dose cleared in about a month. No retatrutide product has FDA approval yet, which also means nobody can tell you how much retatrutide a given vial holds; retatrutide’s price and release date covers where the approval stands.

Stopping before a pregnancy

Here the half-life turns into an instruction. All three semaglutide labels ask women planning a pregnancy to come off the drug two months or more in advance, and each gives semaglutide’s slow clearance as the reason.^[3][4][8] Two months is longer than the five to seven weeks the drug takes to clear, which leaves a margin.

The Zepbound, Saxenda and Foundayo labels name no interval before conception. Each says to stop the drug when a pregnancy is recognized.^[1][5][7] Zepbound’s adds a separate warning for anyone on the pill: tirzepatide can make birth-control pills less reliable, so for the first month on the drug, and the month after every step up in dose, the label wants either a contraceptive that is not taken by mouth or a barrier method such as condoms on top.^[1] Foundayo’s gives 30 days for the same purpose.^[7] What to do when a label is silent is the subject of GLP-1s and trying to conceive.

Before surgery or an endoscopy

These drugs slow the emptying of the stomach, and the Zepbound and Wegovy labels warn of rare reports of food being inhaled into the lungs under general anesthesia or deep sedation. Zepbound’s label says the available data are insufficient to say whether stopping the drug beforehand reduces that risk, and it asks patients to tell their providers before any planned procedure.^[1][3] The half-life tells you how long the drug lingers; how long to hold it before a procedure is a decision for the team doing the procedure, and the current guidance is set out in GLP-1s before endoscopy and surgery.

When the effects wear off

The effects fade as the level in the blood falls, so they do not switch off on a particular day. Weight regain follows over months rather than weeks, and the trial evidence on that is in what happens when you stop a GLP-1. If you stop and then restart, the half-life matters again: the Wegovy label says that after two or more missed weekly doses the dose should be built up again from a lower step, to limit stomach side effects.^[3]

Common questions