Also known as GLP2-T, tirzepatide, mounjaro, zepbound, tirz · Wikipedia
Tirzepatide (LY3298176) is a synthetic 39-amino-acid dual agonist of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, developed by Eli Lilly. It is administered once weekly by subcutaneous injection and is FDA-approved as Mounjaro for type 2 diabetes (2022), as Zepbound for chronic weight management in adults with obesity or overweight with weight-related conditions (2023), and as Zepbound for moderate-to-severe obstructive sleep apnea in adults with obesity (2024). In the pivotal SURMOUNT-1 trial, tirzepatide 15 mg produced mean weight reductions of approximately 21% over 72 weeks in adults without diabetes, the largest effect size of any incretin therapy approved at that time. Tirzepatide is generally considered a reference incretin against which newer multi-receptor agonists are benchmarked.
21%
weight
loss
72 wk
trial
duration
15 mg
weekly
dose
FDA
approved
Zepbound
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Browse all vendorsMechanism of action
Tirzepatide is a synthetic dual agonist of the GIP and GLP-1 receptors engineered on a GIP-based backbone with a C20 fatty diacid attached to Lys20 to enable albumin binding and once-weekly dosing. GLP-1 receptor activation produces glucose-dependent insulin secretion from pancreatic beta cells, suppresses inappropriate glucagon release, slows gastric emptying, and reduces food intake through hypothalamic (arcuate nucleus POMC/AgRP) and brainstem (area postrema, NTS) pathways.
Pharmacokinetic properties
Half-life
~5 days subcutaneous (supports once-weekly dosing)
Routes
subcutaneous
Bioavailability
C20 fatty diacid moiety enables albumin binding for sustained exposure; absolute subcutaneous bioavailability ~80%. Not orally bioavailable.
Amino-acid sequence
39-amino-acid GIP-based backbone with C20 fatty diacid moiety at Lys20; see Coskun et al., 2018, Mol Metab 18:3-14 for full sequence.
Use & research dosing
The FDA-approved label (Mounjaro for T2D, Zepbound for weight management and OSA) prescribes initiation at 2.5 mg subcutaneously once weekly for 4 weeks, then 5 mg weekly, with optional dose escalations of 2.5 mg every 4 weeks up to a maximum of 15 mg weekly. Maintenance doses of 5, 10, or 15 mg are used depending on tolerability and response. In SURMOUNT-1, mean weight loss at 72 weeks was approximately 15% (5 mg), 19.5% (10 mg), and 20.9% (15 mg). Research-source users commonly reported in self-experimentation protocols mirror the approved titration. Slower escalation is sometimes used to limit GI adverse events. Dose adjustment is not required for renal or hepatic impairment per label.
Research-use framing only. SavePeptides sells nothing for human consumption. Doses above reflect reported research / self-experimentation ranges, not clinical recommendations.
Tirzepatide is now the standard-of-care benchmark for incretin therapy. SURMOUNT-1 (NEJM 2022) showed ~20.9% mean weight loss at 72 weeks with 15 mg in adults without diabetes; SURMOUNT-5 (NEJM 2025, head-to-head vs semaglutide 2.4 mg) confirmed superior weight reduction (~20.2% vs ~13.7% at 72 weeks). SURPASS-2 (NEJM 2021) established superiority to semaglutide 1 mg for HbA1c reduction in T2D. SURMOUNT-OSA (NEJM 2024) supported the December 2024 Zepbound label expansion for obstructive sleep apnea, the first pharmacologic OSA indication. SURPASS-CVOT (2025) and SURMOUNT-MMO will define long-term cardiovascular and mortality outcomes. Generic competition is restricted under Lilly patent protection through the mid-2030s; compounded versions ended after the FDA shortage resolution in 2024.
— SavePeptides editorial desk · last updated 2026-05-25
Cautions & contraindications
Research foundation
Facts verified
2026-05-25
Confidence
high
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