Tirzepatide

Overview

Tirzepatide is a dual GIP/GLP-1 receptor agonist approved for type 2 diabetes (as Mounjaro) and chronic weight management (as Zepbound). It goes one step beyond GLP-1-only drugs like semaglutide by also activating glucose-dependent insulinotropic polypeptide (GIP) receptors, which may enhance weight loss and glycemic control. In head-to-head and placebo-controlled trials, tirzepatide has produced some of the largest average weight losses reported for an anti-obesity medication, making it a leading option for many patients and a frequent topic of comparison with semaglutide.

People seek tirzepatide for the same core reasons as other GLP-1-based therapies: better blood sugar control and significant, sustained weight loss when combined with lifestyle changes. It is FDA-approved and prescription-only. As with semaglutide, compounding was discussed during supply shortages, but the FDA has since restricted compounding and warned against unapproved salt forms.

How It Works (Mechanism of Action)

Tirzepatide activates both GLP-1 and GIP receptors. GLP-1 effects include increased insulin release, reduced glucagon, slowed gastric emptying, and reduced appetite. GIP adds further insulin secretion and may have additional effects on fat tissue and appetite. Together, the dual action is thought to explain the strong weight loss and glycemic outcomes seen in trials. The drug is given once weekly by subcutaneous injection and has a long duration of action.

Primary Uses

Weight Management

Tirzepatide (Zepbound) is approved for chronic weight management in adults with obesity or overweight with weight-related conditions. In the SURMOUNT trials, participants lost on average around 15–20% of body weight over 72 weeks, with some achieving over 25% weight loss at higher doses. It is one of the most effective prescription options for weight loss when used as part of a comprehensive program.