Research Index
Tirzepatide, organized like a design system.
A monochrome, citation-first read on the dual GIP and GLP-1 receptor agonist (tirzepatide) — every SURPASS, every SURMOUNT, every approved indication, laid out in plain English.
The short version
Tirzepatide is a once-weekly injection that activates two gut-hormone receptors at the same time — GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) — with a single synthetic molecule. It is FDA-approved for type 2 diabetes (2022), chronic weight management (2023), and obstructive sleep apnea in adults with obesity (2024). In the largest obesity trial to date (SURMOUNT-1, 2,539 adults), the 15 mg dose produced an average of 22.5% body-weight reduction over 72 weeks [1]. A head-to-head comparison against a selective GLP-1 agonist found tirzepatide outperformed it on both blood-sugar control and body weight [3]. The most common side effects are nausea, constipation, and diarrhea, concentrated during dose escalation. What people actually experience — benefits and downsides — is on the effects page.
What tirzepatide is
Tirzepatide is a 39-amino-acid synthetic peptide that activates two gut-hormone receptors at the same time: the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor [14]. Because both incretin pathways are engaged by one molecule, it is described as a dual agonist or co-agonist — the first of its class to reach market.
The peptide is engineered for a long stay in the bloodstream. A C20 fatty di-acid is attached to the backbone so the molecule binds reversibly to albumin, extending the elimination half-life to roughly five days [15]. That is what makes a once-weekly subcutaneous injection possible.
It is approved by the U.S. Food and Drug Administration for three indications: type 2 diabetes (May 13, 2022), chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity (November 8, 2023), and moderate-to-severe obstructive sleep apnea in adults with obesity (December 20, 2024). This site summarizes the evidence behind each of those approvals — and the studies in heart failure with preserved ejection fraction and metabolic-dysfunction-associated steatohepatitis that may shape future ones.
What the trials actually showed
The phase 3 program is unusually large. Across the SURPASS trials (type 2 diabetes) and the SURMOUNT trials (obesity), more than 13,000 participants have been studied, with follow-up extending past three years in some extensions [1][9][19].
The weight-loss numbers from SURMOUNT-1 are the ones most people have seen: at 72 weeks, adults with obesity who took 15 mg once weekly lost an average of 22.5% of their starting body weight, compared with 2.4% on placebo [1]. In SURPASS-2, tirzepatide 15 mg lowered HbA1c by 2.30 percentage points over 40 weeks versus 1.86 with injectable semaglutide 1 mg, with 60% of the 15 mg arm reaching HbA1c at or below 6.5% and at least 10% weight loss [3].
More recent trials extended the story into other organ systems. SURMOUNT-OSA reported up to a 63% reduction in apnea-hypopnea index in adults with moderate-to-severe sleep apnea and obesity at 52 weeks [10]. SUMMIT showed a lower composite of cardiovascular death or worsening heart failure in heart failure with preserved ejection fraction and obesity [11]. SYNERGY-NASH resolved steatohepatitis in 73.3% of the 15 mg arm versus 13.2% on placebo at 52 weeks [12]. SURPASS-CVOT (2025) found tirzepatide non-inferior to dulaglutide for major cardiovascular events with a 16% relative reduction in all-cause mortality over a median four years [13].
How this site is organized
Each major part of the literature gets its own page. The structure mirrors how a design-system reference is laid out — discrete components, named, with the source visible.
Research walks through mechanism, the SURPASS diabetes trials, the SURMOUNT obesity trials, and the newer SURMOUNT-OSA, SUMMIT, and SYNERGY-NASH results. Dosage covers the FDA-labeled titration schedule, half-life, storage, and the renal and hepatic adjustments (there aren't any). FAQ answers the questions that come up most often. References lists every primary source with DOI and PubMed link.
If you only have a minute, the short version: tirzepatide is a once-weekly injection that activates two incretin receptors. It produced the largest weight-loss numbers ever recorded in a phase 3 obesity trial and matches or beats single-agonist GLP-1 therapy on glycemic control. It carries a boxed warning for thyroid C-cell tumors based on rodent studies, and the most common adverse events are gastrointestinal and dose-related.
What this site is not
Shop Tirzepatide is an independent editorial project. It does not manufacture, sell, distribute, or recommend any product. The word "shop" in the domain refers to the way the content is arranged — a catalog of named trials and approved indications — not to a transaction.
Nothing on this site is medical advice. The dose schedules described here are summaries of the U.S. prescribing information and published trial protocols; they are not personal recommendations. Decisions about whether tirzepatide is appropriate, and at what dose, belong to a licensed clinician who knows the patient's history.