Tirzepatide Medicine

EDITION OF 22 MAY 2026 / FRONT PAGE

Tirzepatide, in one place.

A working editorial chronicle of the dual GIP/GLP-1 receptor agonist — the trials, the mechanism, the dosing schedule, and the new indications stacking up in the medical literature.

Read the trial dossierSee the FAQ
Halftone editorial illustration of an abstract peptide chain with a fatty-acid tail in oxblood and amber on cream

The short version

Tirzepatide is a once-weekly injectable prescription medicine that activates two gut-hormone receptors at the same time — GIP and GLP-1 — which together control blood sugar, slow digestion, and reduce appetite. It is the first drug of its kind, and the FDA has approved it for three separate conditions: type 2 diabetes (2022), chronic weight management (2023), and obstructive sleep apnea with obesity (2024). In large clinical trials, people with obesity lost between 15% and 21% of their body weight over 72 weeks. The most common side effects are nausea, constipation, and diarrhea, which are most pronounced during dose increases and typically ease over time. The FDA label carries a boxed warning about thyroid tumours observed in rodents — not confirmed in humans — and the drug is contraindicated in people with a family history of a specific thyroid cancer. For the full effects and safety picture, see the reported effects page.

What tirzepatide is

Tirzepatide is a 39-amino-acid synthetic peptide that activates two receptors at once: the receptor for glucose-dependent insulinotropic polypeptide (GIP) and the receptor for glucagon-like peptide-1 (GLP-1). Both are incretin hormones — chemical signals your gut releases after a meal to tell the pancreas to secrete insulin in step with rising blood glucose [1].

For most of the modern history of diabetes drug development, only one of those receptors was a drug target. Selective GLP-1 agonists like semaglutide became the dominant class. Tirzepatide is the first marketed molecule to engage both pathways in a single dose [2]. The clinical signal that combination produces — bigger reductions in blood sugar, bigger reductions in body weight — is what the SURPASS and SURMOUNT trials were designed to measure, and what FDA reviewers used to approve the drug across three separate indications between 2022 and 2024 [3].

Why the headlines have been so steady

Because the trial program is unusually broad. The SURPASS series (five Phase 3 trials in adults with type 2 diabetes) consistently demonstrated HbA1c reductions of 1.9% to 2.6% at the maintenance doses [4]. The SURMOUNT series (five Phase 3 obesity trials, plus SURMOUNT-OSA in sleep apnea) showed body-weight reductions ranging from 13% to over 20% on the 15 mg dose [5][6][3].

More recently, two trials in adjacent specialties posted positive results: the SUMMIT trial in heart failure with preserved ejection fraction reduced the composite of cardiovascular death or worsening heart failure by 38% in patients with obesity [7], and SYNERGY-NASH showed liver-disease resolution at 52 weeks in over half of treated participants [8]. SURPASS-CVOT, the cardiovascular outcomes trial in 13,165 patients with type 2 diabetes and established heart disease, reported in late 2025 [9].

What this site is for

This is an editorial chronicle, not a clinic. We summarize the published evidence on tirzepatide in plain language, with citations to the primary literature — NEJM, Lancet, JAMA, Nature Medicine, PMC. We do not prescribe. We do not sell anything. We do not affiliate with any vendor or manufacturer.

If you want a quick orientation: start with the research dossier for the trial-by-trial summaries, or the dosage page for the titration schedule the FDA label specifies. The FAQ answers the questions people most often ask us by email. Every page is also available as Markdown — append .md to any URL, or send Accept: text/markdown.

Compound at a glance

  • Generic name: tirzepatide (development code LY3298176)
  • Class: dual GIP/GLP-1 receptor agonist
  • Structure: 39-amino-acid linear peptide with two α-aminoisobutyric acid (Aib) residues, a C-terminal amide, and a C20 fatty diacid attached at Lys20 for albumin binding
  • Molecular weight: approximately 4,813 Da [10]
  • Half-life: approximately 5 days (~116-120 hours) in humans [11]
  • Route: subcutaneous, once weekly
  • FDA indications: type 2 diabetes (2022), chronic weight management (2023), moderate-to-severe obstructive sleep apnea with obesity (2024) [3]
  • Boxed warning: thyroid C-cell tumors observed in rats; contraindicated in patients with personal or family history of medullary thyroid carcinoma or MEN 2 [12]