Tirzepatide

Mounjaro · Zepbound

GLP-1 Receptor Agonist GLP-1 Weight Loss SubQ FDA/EMA Label

Half-life

5 days

Time to Peak

24 hr

Steady State

~25 days

Bioavailability

80%

Dose Range

2.5–15 mg

Frequency

Weekly

Overview

Once-weekly injectable dual GIP/GLP-1 receptor agonist for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound). Demonstrated up to ~21% weight loss in SURMOUNT trials.

Mechanism of Action

Dual GIP and GLP-1 receptor agonist. First-in-class twincretin that activates both incretin receptors for enhanced glycemic control and weight loss.

Dosing Information

Route	Dose Range	Half-life	Tmax	Frequency
Subcutaneous (SubQ)	2.5–15 mg	5 days	24 hr	Weekly

Storage & Handling

2-8C — Refrigerate unused pens. Can store at room temp (up to 30C) for up to 21 days. Do not freeze.

Used in Regimens

3 regimens

GLP-1 Switch — Semaglutide → Tirzepatide

Transition from semaglutide to tirzepatide — typically for improved efficacy or to access dual GIP/GLP-1 mechanism. Often done after plateau on semaglutide. Most patients experience renewed weight loss momentum after switching.

Tirzepatide — start at 2.5mg regardless of prior sema dose.

glp1

Primary

GLP-1 Switch — Tirzepatide → Semaglutide

Transition protocol from tirzepatide to semaglutide — typically due to cost, supply, or insurance coverage change. Approximate dose equivalences: tirzepatide 5mg ≈ semaglutide 0.5mg; tirzepatide 10mg ≈ semaglutide 1mg; tirzepatide 15mg ≈ semaglutide 2mg. Expect temporary appetite increase during transition.

Tirzepatide — final dose before switch.

glp1

Primary

Tirzepatide Full Titration

Complete Mounjaro/Zepbound titration from 2.5mg through to 15mg target maintenance. Titrates every 4 weeks per FDA label. Most patients find their sweet spot between 5mg and 10mg.

Use if stabilising at 10–12.5mg — not everyone needs to reach 15mg

glp1

Primary

Data Sources

FDA Label Mounjaro FDA Prescribing Information
FDA Label Zepbound FDA Prescribing Information

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