Dual GIP / GLP-1 receptor agonist
Tirzepatide half-life
Last reviewed 2026-11-08 · Sources cited for every value
Tirzepatide
FDA-approved as Mounjaro (type 2 diabetes) and Zepbound (chronic weight management; obstructive sleep apnea with obesity).
Reported half-life: 5 days.
Show chart data as a table
| Series | 1× t½ | 2× t½ | 3× t½ | 4× t½ | 5× t½ |
|---|---|---|---|---|---|
| Tirzepatide | 5 days · 50% | 10 days · 25% | 15 days · 12.5% | 20 days · 6.25% | 25 days · 3.125% |
1 half-life
5 days
50% remaining
2 half-lives
10 days
25% remaining
3 half-lives
15 days
12.5% remaining
4 half-lives
20 days
6.25% remaining
5 half-lives
25 days
3.125% remaining
Source, population and method
The Mounjaro label reports an apparent population mean clearance of 0.061 L/h with an elimination half-life of approximately 5 days.
- Reported value
- 5 days
- Measure
- Elimination half-life (source term: “elimination half-life”)
- Species
- Human
- Population
- Healthy subjects and adults with type 2 diabetes (the label states PK is similar between them)
- Route
- Subcutaneous
- Formulation
- Solution for injection (single-dose pen, vial, KwikPen)
- Context
- Population pharmacokinetic analysis
- Method
- Population pharmacokinetic estimate (apparent population mean clearance)
- Study design
- Regulatory label summary of the clinical pharmacology program
- Source type
- Official prescribing information
- Evidence quality
- High
- Last verified
- 2026-11-08
Steady state is reported after 4 weeks of once-weekly administration; mean absolute bioavailability 80 %.
Source: MOUNJARO (tirzepatide) injection, US prescribing information, section 12.3 · DailyMed SetID d2d7da5d-ad07-4228-955f-cf7e355c8cc0 · 2026-08-27
The two tirzepatide labels give different figures for different populations: about 5 days (Mounjaro) and about 5–6 days (Zepbound, overweight or obesity). Both are shown; neither is averaged.
Idealized first-order elimination, R(t) = 100 × 2−t/t½. It ignores absorption, distribution, metabolites, individual physiology and effect duration, and is never a prediction for a person or a basis for timing anything.
Reported tirzepatide half-life estimates
| Source | Half-life | Measure | Population | Route · form |
|---|---|---|---|---|
| Mounjaro | 5 days | Elimination half-life | Healthy subjects and adults with type 2 diabetes (the label states PK is similar between them) | Subcutaneous · Solution for injection (single-dose pen, vial, KwikPen) |
| Zepbound | 5–6 days | Elimination half-life | Adults with overweight or obesity; adults with obstructive sleep apnea and obesity | Subcutaneous · Solution for injection (pen, vial, KwikPen) |
Mounjaro
The Mounjaro label reports an apparent population mean clearance of 0.061 L/h with an elimination half-life of approximately 5 days.
- Reported value
- 5 days
- Measure
- Elimination half-life (source term: “elimination half-life”)
- Species
- Human
- Population
- Healthy subjects and adults with type 2 diabetes (the label states PK is similar between them)
- Route
- Subcutaneous
- Formulation
- Solution for injection (single-dose pen, vial, KwikPen)
- Context
- Population pharmacokinetic analysis
- Method
- Population pharmacokinetic estimate (apparent population mean clearance)
- Study design
- Regulatory label summary of the clinical pharmacology program
- Source type
- Official prescribing information
- Evidence quality
- High
- Last verified
- 2026-11-08
Steady state is reported after 4 weeks of once-weekly administration; mean absolute bioavailability 80 %.
Source: MOUNJARO (tirzepatide) injection, US prescribing information, section 12.3 · DailyMed SetID d2d7da5d-ad07-4228-955f-cf7e355c8cc0 · 2026-08-27
Zepbound
The Zepbound label reports an elimination half-life of approximately 5–6 days in patients with overweight or obesity, and in patients with OSA and obesity.
- Reported value
- 5–6 days
- Measure
- Elimination half-life (source term: “elimination half-life”)
- Species
- Human
- Population
- Adults with overweight or obesity; adults with obstructive sleep apnea and obesity
- Route
- Subcutaneous
- Formulation
- Solution for injection (pen, vial, KwikPen)
- Context
- Population pharmacokinetic analysis
- Method
- Population pharmacokinetic estimate (apparent population mean clearance about 0.06 L/h)
- Study design
- Regulatory label summary of the clinical pharmacology program
- Source type
- Official prescribing information
- Evidence quality
- High
- Last verified
- 2026-11-08
Median Tmax 24 h (range 8–72 h); mean absolute bioavailability 80 %.
Source: ZEPBOUND (tirzepatide) injection, US prescribing information, section 12.3 · DailyMed SetID 487cd7e7-434c-4925-99fa-aa80b1cc776b · 2026-08-28
Where sources differ: The two tirzepatide labels give different figures for different populations: about 5 days (Mounjaro) and about 5–6 days (Zepbound, overweight or obesity). Both are shown; neither is averaged.
Pharmacokinetic context from the labels
Absorption
Mean absolute bioavailability after subcutaneous administration is 80 %, with peak concentrations 8 to 72 hours later.
Clearance
Apparent population mean clearance is about 0.06 L/h. Albumin binding keeps clearance slow; elimination is by proteolysis and fatty-acid metabolism.
Steady state
Both labels report steady state after 4 weeks of once-weekly administration, consistent with a multi-day half-life.
Tirzepatide is FDA-approved as Mounjaro and Zepbound. Arithmetic on its half-life is not a schedule; only the prescribing information and a clinician define how a medicine is used. How half-life works.
What the curve can and cannot tell you
The curve is an idealized first-order elimination model. It is a mathematical illustration of what a half-life means, not a medical prediction. It does not model:
- Patient-specific pharmacokinetics
- Drug absorption from the site of administration
- Multi-compartment distribution
- Active metabolites
- Receptor occupancy
- How long a clinical effect lasts
- Individual blood concentrations
- Drug interactions
- Changes in kidney or liver function
A half-life describes how fast a concentration falls once absorption and distribution are complete. It is not the same as how long an effect lasts, and five half-lives is a mathematical landmark (about 3 % remaining in the idealized model), not a guaranteed washout or a safety threshold. Half-life vs duration of action.
Frequently asked questions
What is the half-life of tirzepatide?
The Mounjaro prescribing information reports an elimination half-life of approximately 5 days. The Zepbound prescribing information reports approximately 5–6 days in patients with overweight or obesity, including those with obstructive sleep apnea.
Why do Mounjaro and Zepbound give different numbers?
They are the same molecule, but each label reports pharmacokinetics for its own populations: type 2 diabetes and healthy subjects for Mounjaro, overweight or obesity for Zepbound. Both values are shown rather than averaged.
How was the half-life measured?
Both labels derive it from population pharmacokinetic analysis (apparent population mean clearance about 0.06 L/h). Steady state is reported after 4 weeks of once-weekly administration.
What makes tirzepatide long-acting?
A C20 fatty diacid side chain binds albumin, which slows clearance and protects the peptide from rapid breakdown. Subcutaneous absorption is also gradual, with peak concentrations reported 8 to 72 hours after administration.
Does the half-life tell me how long tirzepatide works?
No. Half-life describes falling plasma concentrations in an idealized sense. The duration and size of an effect depend on many other factors and are not modelled here.
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