Mounjaro is the brand name of a prescription medication whose active ingredient is tirzepatide, an injectable medicine used primarily to treat type 2 diabetes in adults and children aged 10 years and older.
It belongs to a class of drugs called dual GIP/GLP-1 receptor agonists, meaning it mimics two naturally occurring hormones in the body — glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) — to help manage blood sugar levels.
Mounjaro is given once a week by injection under the skin (subcutaneous injection) and is typically used along with diet and exercise as part of a comprehensive treatment plan for type 2 diabetes.
How Mounjaro Works: Dual Hormone Action
Unlike older diabetes medications that target one pathway, tirzepatide works by activating two hormone receptors at once (GIP and GLP-1). This dual action makes it more effective for blood sugar control than older single-target drugs.
Here’s what this dual mechanism does:
Stimulates insulin release when blood sugar levels are high, helping cells use glucose for energy.
Suppresses glucagon production, reducing the liver’s release of stored glucose.
Slows gastric emptying, which helps moderate the rise in blood sugar after meals and increases fullness.
Reduces appetite, helping with portion control and calorie intake.
Because of these combined effects, Mounjaro not only improves glucose control but also often leads to significant reductions in weight, which can be especially helpful for many people with type 2 diabetes.
Approved Uses of Mounjaro
Type 2 Diabetes
Mounjaro is approved by health authorities, including the U.S. FDA, to improve blood sugar levels in adults and eligible children with type 2 diabetes when used with diet and exercise.
The goal of treatment is to lower blood glucose (measured as HbA1c) and reduce the risk of diabetes-related complications such as nerve, kidney, and heart issues.
Weight Loss (Indirect Effect)
Although Mounjaro is not directly approved for weight loss under its Mounjaro label, many patients experience weight reduction due to its effects on satiety and reduced food intake. Clinical studies show substantial average weight loss in people taking tirzepatide, especially at higher doses.
A closely related drug, Zepbound — which also uses tirzepatide — has been specifically approved in the U.S. for chronic weight management in adults with obesity or overweight individuals with related medical conditions.