Zepbound half-life

Zepbound is tirzepatide, taken weekly, with an elimination half-life of about 5 days. The prescribing information puts steady state at about 4 weeks. Pick a scenario to see the modeled level build, dip after a missed dose, or fade after stopping. Nothing is stored, and no account is needed.

Modeled level as a percent of the steady peak. Baseline ticks mark doses. The tinted band is the steady rhythm.

In this model, levels come within 10% of the steady peak after 3 on-time weekly doses. The prescribing information puts steady state at about 4 weeks.

Elimination half-life: 5 days
Dosing rhythm: Weekly
Steady state, per the label: about 4 weeks

Modeled from the elimination half-life and time to peak in each brand's FDA prescribing information. Real levels vary from person to person. This shows the shape, not your blood level.

Common questions

How long until Zepbound reaches steady levels?

The prescribing information puts steady state at about 4 weeks of on-time weekly doses. In this model, levels come within 10% of the steady peak after 3 doses, and each dose after that tops up a level that no longer changes much week to week.

What happens to levels if I miss a week?

In this model, one missed week lets the level slip to about 19% of the steady peak, compared with a usual low of about 50%; it does not fall to zero, and the rhythm settles back within about 3 doses after resuming. What to do about a missed dose is a question for your pharmacist or prescriber and the brand's official instructions; this page only models the level.

How long does Zepbound stay in your system after stopping?

Zepbound is tirzepatide, with an elimination half-life of about 5 days. In this model, levels fall below half of the steady peak about 7 days after the last dose and below 10% about 3 weeks after it. The usual pharmacology rule of thumb treats a medicine as essentially cleared after about 5 half-lives, about 4 weeks here.

Why show percent of steady state instead of a blood level?

A real concentration in ng/mL depends on dose size, body weight, and absorption differences that public data cannot pin down for any one person. The shape of the curve depends only on the published half-life and time to peak, so the honest way to draw it is relative to its own steady peak: how fast it builds, how gently one missed dose lands, and how slowly it fades.

Is the half-life the same as Mounjaro?

Yes. Zepbound and Mounjaro are both tirzepatide, so the level curve on this page applies to either. They differ in approved use and dose sizes, which this page does not model.

Where the numbers come from

Two label facts per molecule drive everything on this page: the elimination half-life and the time to peak, both from the FDA prescribing information. The curve is a standard one-compartment model built only from those two numbers and the dosing schedule, shown as a percent of the steady peak precisely because an absolute blood level cannot be derived from public data. See how we calculate.

tirzepatide: Mounjaro and Zepbound FDA prescribing information (tirzepatide)

Other medications

Wondering about weight instead?

The Zepbound weight loss calculator projects the published trial curve onto your start weight, and GLP-1 dosing and titration explained covers why doses step up slowly.

General information, not medical advice. This page models an average curve from label averages; it is not your blood level, and it never tells you when to take a dose. Missed-dose instructions live in your brand's prescribing information and with your pharmacist or prescriber.

Track the doses themselves

This page models an average curve. Log your actual doses in SteadyRange and see them alongside your weight, glucose, and time in range, on a private log you control.

Start a free log Project weight on a GLP-1