Tirzepatide (LY3298176): GIP/GLP-1 Dual Agonist Research

Tirzepatide (Eli Lilly code LY3298176) is a dual agonist — it activates both the GIP receptor and the GLP-1 receptor with a single molecule. It's the compound behind Mounjaro (approved for type 2 diabetes) and Zepbound (approved for obesity), and its trial results reset expectations for how much weight and glucose control an incretin drug could deliver. It's built on the GIP peptide backbone with a fatty-acid chain that allows once-weekly dosing.

Research Background

Tirzepatide was developed to test a specific question: would adding GIP-receptor activity to GLP-1 do better than GLP-1 alone? Lilly published the discovery and early proof-of-concept work (Coskun et al., *Molecular Metabolism*, 2018), then ran two large phase 3 programs — SURPASS in type 2 diabetes and SURMOUNT in obesity. Those led to FDA approval as Mounjaro in 2022 and Zepbound in 2023, with later work (SYNERGY-NASH) extending into liver disease.

How It Works

GIP and GLP-1 are both incretin hormones — gut signals that boost insulin release when blood sugar is high. By engaging both receptors, tirzepatide improves glucose-dependent insulin secretion and beta-cell function while the GLP-1 side (plus central GIP action) reduces appetite and slows gastric emptying. In preclinical work the combined GIP/GLP-1 signal reduced food intake and body weight more than a GLP-1 agonist alone, which is the rationale for its outsized effect on both glucose and weight.

What the Research Shows

All of the pivotal data is from large, published human trials:

• SURPASS-1 (Rosenstock et al., *The Lancet*, 2021): as monotherapy in type 2 diabetes, HbA1c fell by roughly 1.9–2.1 percentage points across doses, with up to about 11% weight loss at the top dose.
• SURPASS-2 (Frías et al., *NEJM*, 2021): head-to-head against semaglutide 1 mg, tirzepatide was superior on both HbA1c and weight.
• SURMOUNT-1 (Jastreboff et al., *NEJM*, 2022): in obesity without diabetes, mean weight reduction reached about 21% at the 15 mg dose (treatment-regimen estimand), with fat mass falling far more than lean mass.
• SURMOUNT-2 (Garvey et al., *The Lancet*, 2023): in obesity with type 2 diabetes, mean weight reduction was about 13–16% across doses versus ~3% placebo.
• SYNERGY-NASH (Loomba et al., *NEJM*, 2024): in metabolic dysfunction-associated steatohepatitis, MASH resolution without worsening fibrosis reached 52–73% across doses at 52 weeks, versus 13% on placebo.

As with the rest of the class, gastrointestinal effects (nausea, diarrhea) were the most common adverse events and were generally dose-related. Full citations are in the References section below.

Storage & Handling

Tirzepatide is supplied in lyophilized (freeze-dried) form. Store at -20°C or below, away from light and moisture. Reconstitute immediately before use with a sterile solvent suited to your protocol, and avoid repeated freeze-thaw cycles.

Frequently Asked Questions

How is tirzepatide different from semaglutide? Semaglutide is a single GLP-1 receptor agonist. Tirzepatide adds GIP-receptor activity, and in a direct trial (SURPASS-2) it outperformed semaglutide on glucose and weight.

What are Mounjaro and Zepbound? Both are tirzepatide — Mounjaro is the brand approved for type 2 diabetes, Zepbound the brand approved for obesity. This product is sold strictly for research use only.

What purity does Dynamite Research Peptides provide? Our tirzepatide is 99%+ purity with a Certificate of Analysis for every batch, verified by HPLC and mass spectrometry.

All products are for research use only — not for human or animal consumption.