Journal September 16, 2026 5 min read

Tirzepatide: mechanism of action

Tirzepatide is a dual GIP and GLP-1 receptor agonist. This page summarises its mechanism of action and the research models in which it has been studied.

peptides-pro Editorial

Tirzepatide (LY3298176) is a synthetic peptide that acts as a dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors [6]. It is supplied for laboratory research use only. The evidence block for this page does not provide its sequence, molecular formula, or molecular weight.

The work described here centres on the incretin receptor family — specifically GIP and GLP-1 receptor signalling — and on the downstream effects of activating both receptors.

Research Studies

Tirzepatide and preoperative weight loss before one anastomosis gastric bypass

A clinical trial is comparing three preoperative strategies before one anastomosis gastric bypass (OAGB) for severe obesity: tirzepatide for 60 days, a ketogenic diet for 4 weeks, or standard care [1]. The primary outcome is weight loss one year after surgery. Secondary outcomes include safety, surgical outcomes, and improvement in obesity-related conditions such as diabetes, high blood pressure, and sleep apnea [1].

Tirzepatide and pathologic response in endometrial hyperplasia and grade 1 endometrial cancer

A phase II trial is studying whether adding tirzepatide injections to a levonorgestrel intrauterine device (LNG-IUD) improves pathologic response — the absence of cancer cells in tissue samples after treatment — in women with endometrial atypical hyperplasia/endometrial intraepithelial neoplasia (AH/EIN) or grade 1 endometrial cancer who are overweight or obese [2]. The background notes that over half of endometrial cancer cases are thought to be attributable to being overweight and obese, and that the risk relationship appears to be weight dependent [2].

Tirzepatide and levonorgestrel IUD therapy for EIN and early-stage endometrial cancer

A single-arm study is evaluating the feasibility, safety, and preliminary efficacy of tirzepatide in combination with standard LNG-IUD therapy in patients with endometrial intraepithelial neoplasia (EIN) or grade 1 endometrioid endometrial carcinoma with co-existing obesity and metabolic risk factors [3]. Participants receive tirzepatide once weekly while continuing standard clinical management with an LNG-IUD; treatment decisions remain at the discretion of the treating physician [3]. The primary objective is pathologic response at approximately 6 months, with secondary objectives including changes in metabolic parameters [3].

Tirzepatide and real-world outcomes in Pakistani adults with obesity, prediabetes, and type 2 diabetes

A multicentre, prospective, observational study is following 330 adults starting tirzepatide as part of routine care across ten diabetes and endocrinology centres in Pakistan [4]. All participants have obesity and are grouped into three cohorts by blood sugar status at baseline: obesity without diabetes, prediabetes with obesity, and type 2 diabetes [4]. The study notes that tirzepatide is already approved for type 2 diabetes and for obesity, but that there is very little information on how it works for people in South Asia, and none from Pakistan specifically [4].

Tirzepatide and central centrifugal cicatricial alopecia

A pilot clinical trial is investigating whether tirzepatide can treat active central centrifugal cicatricial alopecia (CCCA), a type of permanent scarring hair loss, in adults [5]. The trial aims to determine whether tirzepatide improves the symptoms and signs of active CCCA, whether it changes the activity of genes in the scalp — especially genes related to scarring — and whether it promotes hair regrowth [5]. Participants inject tirzepatide once a week for 12 months, attend clinic visits for scalp examinations and photographs, undergo scalp biopsies at baseline and after 6 months, and have blood tests [5].

Tirzepatide and postbariatric hypoglycemia after Roux-en-Y gastric bypass

A case series described 3 patients with postbariatric hypoglycemia (PBH) following Roux-en-Y gastric bypass who were treated with tirzepatide [6]. All patients presented with symptomatic hypoglycemia characterised by episodes of diaphoresis, visual disturbances, confusion, and documented low blood glucose levels occurring postprandially [6]. Conventional management strategies, including dietary modifications, acarbose, and other pharmacotherapies, were either partially effective or limited by side effects [6]. Initiation of tirzepatide was then undertaken [6].

Tirzepatide and bowel frequency in ileal pouch-anal anastomosis

A clinical trial is testing whether tirzepatide (Zepbound) can decrease bowel frequency in patients with an ileal pouch-anal anastomosis (IPAA or pouch) better than standard-of-care anti-diarrheal therapy [7]. Participants visit the clinic 5 times, answer daily symptom questions, take the study product as instructed, and provide a stool sample 4 times [7].

Tirzepatide and stomach emptying in type 1 diabetes with overweight or obesity

A study is examining how tirzepatide affects stomach emptying in participants with type 1 diabetes mellitus (T1DM) and overweight or obesity [8]. Participation lasts about 8 weeks, including screening and follow-up [8].

Tirzepatide and glycaemic control in early uncontrolled type 2 diabetes

A reference-only report indicates that in adults with early uncontrolled type 2 diabetes, tirzepatide compared with intensified conventional care reduced HbA1c levels and weight at 2 years [10].

Tirzepatide and weight regain after discontinuation

A reference-only reconstructed aggregate-data Bayesian longitudinal meta-analysis estimated post-discontinuation weight-regain trajectories after semaglutide or tirzepatide, and explored predictors of faster regain [11].

Tirzepatide and major cardiovascular events in type 2 diabetes with cardiovascular disease

A reference-only comment discusses comparative effectiveness of tirzepatide versus dulaglutide or semaglutide on major cardiovascular events in type 2 diabetes and cardiovascular disease, based on two target-trial emulations [12].

Tirzepatide and oral health

A reference-only paper addresses emerging oral health implications for oral medicine practice [9].

If you are reading this for personal health reasons

This material is sold for laboratory research only. We do not provide dosing or medical guidance. Anyone considering a compound for themselves should speak to a licensed clinician.