How Long Does Mounjaro Take to Leave Your System?

A medicine's half-life describes how long it takes for the concentration in your body to reduce by half. According to the electronic Medicines Compendium (eMC), tirzepatide's half-life is approximately five days. Because several half-lives are needed for a medicine to become negligible in the body, most pharmacokinetic guidelines consider a substance effectively cleared after around five half-lives — which places the full clearance window for tirzepatide at roughly four to five weeks after your last injection.

What this means in practice

This extended presence in the body is partly why Mounjaro is injected just once a week — the medicine remains active at meaningful levels throughout the seven-day interval between doses. It also means that effects (both the appetite-regulating benefits and any reported side effects) do not disappear overnight if you stop or miss a dose. Many people report that appetite and food noise begin to return gradually over the days and weeks following their last injection, though individual experience varies considerably.

How does this compare to Wegovy?

Semaglutide, the active substance in Wegovy, also has a long half-life — approximately one week, according to its eMC entry. This means Wegovy follows a broadly similar pattern: once-weekly dosing, with the medicine persisting in the body for several weeks after the last injection. If you want to explore how long Wegovy takes to become active, that page covers the onset side of the timeline in more detail.

Factors that can influence clearance

Individual factors such as body weight, kidney and liver function, and metabolic rate can all influence how quickly any medicine is processed. These personal variables are another reason why any questions about stopping, pausing, or changing your injections belong with your prescriber or doctor — they know your full clinical picture. For more on how tirzepatide works once it is in your system, see our overview of how Mounjaro works, and for context on how quickly the medicine becomes effective after starting, take a look at how long Mounjaro takes to work.

If you are thinking about clearance timelines, you are likely paying close attention to how you feel across your weekly cycle — and that is exactly where logging becomes valuable. GLP Trackr's side-effect and symptom tracker lets you record how you feel each day, so you can spot patterns across your dose schedule: when effects feel strongest, when they ease, and how things shift if a dose is delayed or missed.

Alongside symptom tracking, the dose-logging feature keeps a clear record of every injection — date, dose strength, and site — so you always have an accurate timeline to refer back to or share with your prescriber at your next appointment. If you want to explore what others track across the clearance window, the Mounjaro system clearance page looks at this in more detail.

If symptoms feel severe, persistent, or are causing you concern at any point — whether that is during treatment or after stopping — contact your healthcare professional promptly. GLP Trackr helps you record what you are experiencing so you can have a more informed conversation with them; it is not a substitute for their advice.

Start logging your doses and daily symptoms today — GLP Trackr is free to try for 7 days on the App Store and Google Play.