Tirzepatide in type 1 diabetes: beyond mere weight loss.

BACKGROUND: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have revolutionized treatment for type 2 diabetes mellitus (T2DM), obesity and beyond. Current research focuses on the use of the dual agonist of glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR), tirzepatide. AREAS COVERED: This narrative review focuses on the clinical potential of tirzepatide in type 1 diabetes mellitus (T1DM). A literature search in PubMed/MEDLINE, Scopus and Google Scholar until March 2026 was conducted using appropriate keywords. Glycated hemoglobin (HbA) was reduced by up to 0.9% and body weight by up to 23.4% corresponding to a reduction in body-mass index by up to 9.0 kg/m. Continuous glucose monitoring (CGM) has shown that time in range (TIR) increased by up to 18.0%, almost exclusively due to reduced time above range (TAR). Daily insulin requirements were reduced by up to 38 units/day. EXPERT OPINION: Tirzepatide was associated with optimized glycemic control and reduced insulin requirements. These benefits were partly, but not exclusively, mediated by weight loss. Currently available studies are largely observational and have included subjects with overweight or obesity. Future randomized controlled trials are now required to further corroborate these promising findings.