Science Explained

GLP-1 vs GIP: What's the Difference?

Understanding the hormones behind the new generation of weight loss injections.

The Basics

Both GLP-1 (Glucagon-like peptide-1) and GIP (Glucose-dependent insulinotropic polypeptide) are incretin hormones. These are hormones released by your gut after you eat.

They play a crucial role in how your body handles sugar (glucose) and how hungry you feel.

GLP-1

Slows down stomach emptying
Signals "fullness" to the brain
Stimulates insulin release
Inhibits glucagon (sugar release)
Found in: Wegovy, Saxenda, Mounjaro

GIP

Enhances insulin secretion
Improves fat metabolism
May reduce nausea side effects of GLP-1
Works with GLP-1 for stronger effect
Found in: Mounjaro only

The "Twincretin" Effect

This is why Mounjaro (Tirzepatide) is often called a "twincretin." It mimics BOTH GLP-1 and GIP.

Scientists believe this dual action is the key to why Mounjaro has shown superior weight loss results compared to medications that only target GLP-1 (like Wegovy and Saxenda). The GIP component seems to boost the effectiveness of GLP-1 while potentially helping the body burn fat more efficiently.

Want to compare the medications?

See how Mounjaro and Wegovy stack up against each other.

Compare Mounjaro vs Wegovy

Medical References & Sources

Last Medically Reviewed: April 2026