Peptides Academy
Tirzepatide
Mounjaro / Zepbound
Tirzepatide is a 39-amino-acid synthetic peptide engineered as a dual agonist of both the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor. A C20 fatty diacid modification enables albumin binding, extending half-life to permit once-weekly subcutaneous dosing. The rationale for dual agonism: while GLP-1 agonism alone provides robust glycemic and weight benefits, adding GIP agonism appears to further enhance insulin sensitivity and fat oxidation. The SURPASS trials (type 2 diabetes) showed HbA1c reductions of 2.0–2.5% — exceeding semaglutide head-to-head — and the SURMOUNT trials (obesity) demonstrated mean weight reduction approaching 22% at the highest dose, the largest ever reported for a non-surgical intervention. Tolerability and adverse-event patterns resemble GLP-1 agonist-class drugs: nausea, vomiting, diarrhea, and constipation dominate and attenuate with dose escalation. The SURMOUNT-5 head-to-head (2024–2025) reported approximately 20% weight loss with tirzepatide versus ~15% with semaglutide at maximum tolerated doses over 72 weeks.
Source references
Specifications
| Dose Range | 2.5–15 mg weekly (escalating) |
| Origin / Manufacturer | Synthetic |
| Regulatory Status | FDA-approved (Mounjaro T2D, Zepbound obesity) |
| Active Components | Tirzepatide |
| Storage | Refrigerate 2–8°C |
| Form Factor | Prefilled pen (weekly subcutaneous) |
Frequently Asked Questions
Sources & References
Every clinical claim on this page traces to a primary peer-reviewed source.
- 1Jastreboff AM, Aronne LJ, Ahmad NN, et al.. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038 PMID:35658024
- 2Frías JP, Davies MJ, Rosenstock J, et al.. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2). New England Journal of Medicine. 2021;385(6):503-515. doi:10.1056/NEJMoa2107519 PMID:34170647
- 3Aronne LJ, Sattar N, Horn DB, et al.. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity (SURMOUNT-4). JAMA. 2024;331(1):38-48. doi:10.1001/jama.2023.24945 PMID:38078870
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