The Peptide Atlas
Tirzepatide
A weekly peptide that acts like two gut hormones at once, GLP-1 and GIP.
Class
Dual GIP/GLP-1 receptor agonist
Evidence
Established
Status
FDA-approved (Mounjaro, Zepbound); also made by compounding pharmacies.
Forms
Weekly injection
What people use it for
Weight loss, usually by people comparing it directly against semaglutide.
The signal
Your gut releases several hormones when you eat, and they work together: GLP-1 tells your brain you're full, GIP helps your body handle the incoming fuel and appears to make the GLP-1 signal work better. Tirzepatide activates both receptors, where semaglutide activates one.
How it works
It's built on the GIP hormone's structure, modified so it also fits the GLP-1 receptor and lasts about a week. The practical effect is the same direction as semaglutide, with more of it: less hunger, earlier fullness, quieter food thoughts.
What the research shows
In the SURMOUNT-1 trial, adults lost 20.9% of their body weight on average at the highest dose over 72 weeks, the largest reduction recorded for a weight-loss medication at the time [1]. It was first developed and approved for type 2 diabetes, so a large trial program exists there too [2].
What people get wrong
That it's "stronger semaglutide." It's a different molecule working through two receptors instead of one. The trials do show more average weight loss, but side effects, dosing, and how any one person responds are their own story, which is why the choice between them is a conversation with a doctor and not a leaderboard.
Pepvio prescribes this through licensed U.S. physicians and pharmacies. Pepvio's GLP-1 program
References
- Jastreboff AM et al., N Engl J Med (2022). Tirzepatide Once Weekly for the Treatment of Obesity. PubMed
- Karagiannis T et al., J Endocrinol Invest (2026). Analysis of the efficacy and safety of liraglutide, semaglutide, and tirzepatide for the treatment of type 2 diabetes. PubMed
Last reviewed 2026-08-24. Every reference is verified against the primary literature at review time. How the Atlas grades evidence