What Is Tirzepatide?

Also known as: Mounjaro, Zepbound, GIP/GLP-1

Tirzepatide is Eli Lilly's dual GIP/GLP-1 receptor agonist — sold as Mounjaro (diabetes) and Zepbound (weight loss). By activating two incretin receptors instead of one, it produced the strongest results of any approved obesity drug: over 20% average body-weight loss in the SURMOUNT trials.

The GIP component appears to amplify fat-mass reduction and insulin sensitivity while paradoxically improving GI tolerability relative to effect size. Head-to-head against semaglutide (SURMOUNT-5), tirzepatide came out ahead on weight loss.

What is Tirzepatide studied for?

Side effects & safety

Same class profile as semaglutide — nausea, vomiting, constipation during titration; rare pancreatitis and gallbladder events; thyroid C-cell tumor warning from rodent data. Larger vial sizes in the gray market make dosing errors a bigger practical hazard.

Legal & approval status

FDA/EMA-approved pharmaceutical. Compounded/research-market versions occupy the same legal gray zone as gray-market semaglutide.

Typical dosing at a glance

Commonly reported protocols use 2.5 mg–15 mg, 1x weekly, titrated up, via subcutaneous injection. For the mixing math — how much bacteriostatic water, exact syringe units, doses per vial — see the Tirzepatide reconstitution calculator →

Related peptides

What is Semaglutide?What is Retatrutide?What is Cagrilintide?What is AOD-9604?What is HGH Fragment 176-191?

Educational overview based on published research and commonly reported community protocols — not medical advice, and not an endorsement of any compound. Consult a licensed healthcare provider.