Tirzepatide, a 39-amino-acid synthetic peptide that activates both GIP and GLP-1 receptors, consistently reduced HbA1c and body weight in SURPASS phase 3 trials for type 2 diabetes.
First-in-class dual GIP/GLP-1 agonistTirzepatide is a 39-amino-acid synthetic peptide that simultaneously activates both GIP and GLP-1 receptors, producing greater blood sugar and weight improvements than single-receptor drugs.
What the researchers found
Tirzepatide is a synthetic 39-amino-acid peptide based on the GIP sequence that acts as a dual GIP and GLP-1 receptor agonist. Across the SURPASS phase 3 trial program, tirzepatide consistently demonstrated significant HbA1c reductions and weight loss benefits as monotherapy and as add-on therapy to various antihyperglycemic drugs. The pharmacokinetics were similar in patients with kidney and hepatic impairment, with metabolites excreted through urine and feces. Common adverse events were gastrointestinal in nature.
Why it matters
Tirzepatide represents a paradigm shift in incretin-based therapy by targeting two hormone pathways instead of one. The dual mechanism appears to produce greater blood sugar control and weight loss than GLP-1-only drugs, while maintaining a manageable safety profile. As a 39-amino-acid peptide, it demonstrates how sophisticated peptide engineering can create therapeutics with dual receptor activity from a single molecule.
How the study worked
Narrative review summarizing the pharmacology, pharmacokinetics, pharmacodynamics, and clinical trial evidence (SURPASS program) for tirzepatide in the management of type 2 diabetes mellitus.
What this study cannot tell us
As a review article, this paper does not present original data. At the time of publication (2023), tirzepatide was approved for diabetes but obesity approval was pending. The review focuses primarily on SURPASS trial data, which may not fully represent real-world effectiveness and adherence. Long-term cardiovascular outcomes and safety data beyond the trial periods were not yet available.
How to read the evidence
This is a narrative review summarizing the SURPASS phase 3 clinical trial program, which includes multiple large randomized controlled trials. The underlying evidence is strong, but this paper is a summary rather than original research.
When this study was published
Published in 2023, this review covers tirzepatide's initial diabetes approval. Since then, the drug has also been approved for obesity (Zepbound) and additional indications are being studied.
The bigger picture
Tirzepatide's dual agonism concept has opened the door to multi-receptor peptide drugs. Following its success, the pharmaceutical industry is now developing triple agonists (GIP/GLP-1/glucagon) and other combinations. As the first-in-class dual agonist, tirzepatide proved that targeting multiple incretin pathways simultaneously produces superior outcomes, reshaping diabetes and obesity drug development.
Questions still open
- How does tirzepatide's long-term cardiovascular safety compare to GLP-1-only agonists?
- What is the relative contribution of the GIP versus GLP-1 pathway to tirzepatide's clinical effects?
- Could the dual agonist concept be extended to triple agonists for even greater efficacy?
Common questions
What makes tirzepatide different from semaglutide (Ozempic/Wegovy)?
Is tirzepatide a peptide?
Read the original research
Tirzepatide: A Dual Glucose-dependent Insulinotropic Polypeptide and Glucagon-Like Peptide-1 Agonist for the Management of Type 2 Diabetes Mellitus.
American journal of therapeutics, 30(1), e26-e35
Citation
Wong, Elaine; Cope, Rebecca; Dima, Lorena; Nguyen, Timothy. (2023). Tirzepatide: A Dual Glucose-dependent Insulinotropic Polypeptide and Glucagon-Like Peptide-1 Agonist for the Management of Type 2 Diabetes Mellitus.. American journal of therapeutics, 30(1), e26-e35. https://doi.org/10.1097/MJT.0000000000001588