Source: FDA label
| Molecular formula | C225H348N48O68 |
|---|---|
| Molecular weight | 4813 g/mol |
| Registered trials | 285 |
| PubChem CID | 166567236 |
| Drug class | Glucose-dependent Insulinotropic Polypeptide Receptor Agonist [EPC] |
| Brand names | MOUNJARO |
Boxed warning: The FDA label for this compound includes a boxed warning, the FDA's strongest safety warning. See the full prescribing information for details.
Mechanism of Action
12.1 Mechanism of Action Tirzepatide is a GIP receptor and GLP-1 receptor agonist. It contains a C20 fatty diacid that enables albumin binding and prolongs the half-life. Tirzepatide selectively binds to and activates both the GIP and GLP-1 receptors, the targets for native GIP and GLP-1. Tirzepatide enhances first- and second-phase insulin secretion, and reduces glucagon levels, both in a glucose-dependent manner.
Key takeaways
- Tirzepatide is approved as Mounjaro for glycemic control in type 2 diabetes, alongside diet and exercise.
- It works by activating both GIP and GLP-1 receptors, boosting insulin release and lowering glucagon.
- The label carries a boxed warning.
- More than 285 registered trials have studied tirzepatide, spanning diabetes, weight management, and other uses.
- The most reported issues involve dosing errors and gastrointestinal symptoms like nausea and diarrhoea.
What Tirzepatide Is
Tirzepatide is a synthetic peptide that acts as a dual agonist at the GIP and GLP-1 receptors, two hormone pathways involved in blood sugar regulation. A fatty acid segment built into its structure binds albumin in the blood, which extends how long the drug stays active. By activating both receptors at once, tirzepatide increases insulin release and reduces glucagon output, and it does so in a way that responds to current glucose levels rather than working at a fixed rate.
What Tirzepatide Is Approved For
Tirzepatide is approved under the brand name Mounjaro as an add-on to diet and exercise to improve blood sugar control in adults and in children 10 years of age and older with type 2 diabetes. The label for this product carries a boxed warning, which prescribers and patients are advised to review directly with a healthcare provider.
What the Evidence Shows
Tirzepatide has been studied in more than 285 registered clinical trials. One completed Phase 3 trial examined its use for maintaining weight loss in people with obesity or who were overweight. Other ongoing work includes an early-phase trial recruiting participants to look at tirzepatide's effects related to alcohol use disorder, reflecting research interest beyond its approved diabetes indication.
Reported Side Effects
Among adverse event reports associated with tirzepatide, the largest categories involve dosing mistakes, including incorrect dose administered (28,115 reports) and extra dose administered (9,000 reports), which likely reflect use of an injectable product rather than a specific safety signal. Gastrointestinal symptoms are also commonly reported, led by nausea (14,290), diarrhoea (8,305), and vomiting (6,887), alongside injection site pain (13,177). Reports of off label use (8,291) and drug ineffective (5,415) were also frequent. These figures represent counts of submitted reports, not confirmed rates of occurrence or proof that the drug caused the event.
FAQ
What is tirzepatide approved to treat?
Tirzepatide, sold as Mounjaro, is approved to improve blood sugar control in adults and children 10 years and older with type 2 diabetes. It is meant to be used alongside diet and exercise rather than as a standalone treatment.
How does tirzepatide work in the body?
Tirzepatide activates both the GIP and GLP-1 receptors, two hormone pathways that influence insulin and glucagon release. This dual action increases insulin secretion and lowers glucagon in a way that adjusts to current glucose levels, and a built-in fatty acid segment helps the drug remain active longer.
Does tirzepatide have a boxed warning?
Yes, the FDA label for tirzepatide (Mounjaro) includes a boxed warning. Patients should discuss the specifics of this warning with a prescriber before starting treatment.
What are the most commonly reported side effects of tirzepatide?
The most frequently reported issues include dosing errors, such as incorrect or extra doses administered, along with gastrointestinal symptoms like nausea, diarrhoea, and vomiting, plus injection site pain. These come from adverse event report counts, which reflect submitted reports rather than confirmed rates or causation.
Is tirzepatide being studied for uses beyond diabetes?
Yes, tirzepatide has been the subject of more than 285 registered clinical trials, including research into weight loss maintenance and an early-phase study exploring its effects related to alcohol use disorder. These uses are separate from its current approved indication for type 2 diabetes.
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Sources: DailyMed label ClinicalTrials.gov FDA FAERS PubChem
Updated 2026-08-03