What is Tirzepatide?
Tirzepatide is a once-weekly dual GIP and GLP-1 receptor agonist, marketed under the brand name Mounjaro for type 2 diabetes and Zepbound for weight management. In clinical trials, it has produced some of the largest weight-loss results ever recorded for a non-surgical intervention.
Research peptide vendors sell tirzepatide as a lyophilized vial that buyers reconstitute and self-inject weekly. It is one of the most-purchased compounds in the peptide space in 2025–26, driven by the explosion of GLP-1-class drugs.
How it works
- Activates GLP-1 (glucagon-like peptide-1) receptors, slowing gastric emptying and reducing appetite.
- Activates GIP (glucose-dependent insulinotropic polypeptide) receptors, improving insulin sensitivity and lipid metabolism.
- The dual action is why tirzepatide tends to outperform single-agonist GLP-1s like semaglutide on weight outcomes.
Primary effects
- Significant appetite reduction
- Weight loss (avg ~22% in clinical trials)
- Improved blood-glucose control
- Reduced cardiovascular risk markers
Common side effects
- Nausea (especially during titration)
- Constipation or diarrhea
- Fatigue in first few weeks
- Injection-site irritation
- Rare reports of pancreatitis — discontinue if severe abdominal pain