Metabolic

Tirzepatide

GIP / GLP-1 dual receptor agonist

Dual incretin agonism — engineered from the native GIP sequence.

Half-life

~ 5 days (once-weekly dosing)

Mol. weight

4810.5 g/mol

Sequence

GIP-based dual GIP/GLP-1 agonist (modified peptide)

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Overview

Tirzepatide is a once-weekly injectable peptide engineered from the native GIP sequence with dual agonist activity at both the GIP and GLP-1 receptors. In the SURMOUNT-1 obesity trial, the 15 mg dose produced a mean weight reduction of ~20.9%, with 89–91% of participants on 10–15 mg achieving ≥10% weight loss. In the SURPASS program it delivered superior glycemic control and weight loss versus semaglutide 1 mg, and in the head-to-head SURMOUNT-5 trial it outperformed semaglutide (Wegovy) for weight reduction over 72 weeks (−20.2% vs −13.7%).

Mechanism of action

Tirzepatide is a biased, imbalanced dual agonist: it is engineered from the GIP backbone and activates both GIP and GLP-1 receptors, but with greater potency at GIP. GIP activation is thought to synergize with GLP-1 receptor activation, and tirzepatide's biased signaling (low β-arrestin recruitment, little receptor internalization) may explain its superior activity on target cells versus a monoagonist. The dual action amplifies glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and reduces appetite — producing greater weight loss than GLP-1 monoagonism.

Researched benefits

Mean weight loss ~20.9% at 15 mg (SURMOUNT-1) and ~20.2% vs 13.7% for semaglutide (SURMOUNT-5)
Superior HbA1c reduction vs semaglutide 1 mg and basal insulins (SURPASS program)
89–91% of 10/15 mg participants achieved ≥10% weight loss (SURMOUNT-1)
Improvements in waist circumference, BP, lipids, liver fat (up to 47% LFC reduction in SURPASS-3)
Favorable body-composition shift (fat reduction ~3× lean reduction)

Considerations

Gastrointestinal effects (nausea, diarrhea, vomiting, constipation) are dose-dependent
Dose titration is required to improve tolerability
Loss of lean mass accompanies weight loss; resistance training advised
Rare risks: pancreatitis, gallbladder events; requires medical supervision

Key Academic Literature & Studies

Search more in PubMed

Peer-reviewed citations and clinical trials evaluating Tirzepatide in scientific literature.

Articles & logs

Research2026-09-13·8 min

Why Two Receptors Beat One

The GIP + GLP-1 synergy behind tirzepatide's superior weight-loss numbers.

By Dr. M. Reyes

Research2026-09-02·7 min

SURMOUNT-1: The Obesity Trial That Set a New Bar

Adults lost nearly 21% of body weight on the 15 mg dose — how the trial was designed.

By Editorial Team