Tirzepatide
Dual GLP-1/GIP agonist with superior weight loss to semaglutide — 22.5% body weight reduction in SURMOUNT-1.
Research facts
| Half-life | ~5 days |
|---|---|
| Route | SubQ (weekly) |
| Typical dose | 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg/week |
| Frequency | Once weekly |
| Solvent | Pre-filled pen |
| pH | N/A — commercial formulation |
| Stability | Refrigerated |
Mechanism of action
Tirzepatide is a once-weekly injectable dual GIP/GLP-1 receptor agonist — a single molecule that simultaneously activates both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptors. The GIP component enhances insulin secretion, reduces glucagon, and may independently promote adipocyte lipid metabolism. The SURMOUNT clinical trial programme demonstrated 22.5% mean body weight reduction at 72 weeks at the 15mg dose — the highest ever recorded in an RCT for a pharmacological agent. Tirzepatide surpasses semaglutide across all weight endpoints and glycaemic endpoints.
Documented effects (research-model)
- S-tier: 22.5% body weight reduction (SURMOUNT-1) — highest in RCT history
- Superior glycaemic control vs. semaglutide in T2DM
- Better nausea profile than semaglutide at equivalent weight-loss doses
- Significant visceral and hepatic fat reduction
- Sleep apnoea improvement (SURMOUNT-OSA)
- Strong cardiovascular outcomes data (SURPASS-CVOT ongoing)
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Zepbound (obesity) | Titrate: 2.5mg q4w → 5mg → 7.5mg → 10mg → 12.5mg → 15mg | Once weekly SubQ | Ongoing | Zepbound pre-filled pen |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
- Retatrutide N/A
Triple agonist next generation — not combined.
Myths & misconceptions
Evidence gaps
- Long-term cardiovascular outcomes trial (SURPASS-CVOT) still completing.
- Renal outcomes data less mature than semaglutide.
- Optimal combination with GLP-1 analogues or other metabolic drugs not established.
Safety notes
FDA-approved with large RCT safety database. Similar GI side effect profile to semaglutide. Medullary thyroid carcinoma risk theoretical (rodent signal). Pancreatitis risk. Not for use in personal/family history of medullary thyroid carcinoma or MEN2.
Biomarkers to monitor
Primary-source citations
- PMID 35658024 — Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1) (N Engl J Med. 2022)
Frequently asked
What is Tirzepatide?
Tirzepatide (Mounjaro / Zepbound — GLP-1 + GIP Dual Agonist) is a research compound classified in our library as Tier S — Overwhelming human data — approved and prescribed.. Dual GLP-1/GIP agonist with superior weight loss to semaglutide — 22.5% body weight reduction in SURMOUNT-1.
What is the evidence tier for Tirzepatide?
We classify Tirzepatide as Tier S: Overwhelming human data — approved and prescribed. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of Tirzepatide?
For Tirzepatide, typical research dose is 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg/week, route is SubQ (weekly), half-life is ~5 days. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
Is Tirzepatide safe?
FDA-approved with large RCT safety database. Similar GI side effect profile to semaglutide. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.