A Study to Evaluate the Effect of Retatrutide on Insulin Secretion and Insulin Sensitivity in Adult Participants With Type 2 Diabetes Mellitus

Inclusion Criteria: * Have been diagnosed with Type 2 Diabetes Mellitus (T2DM) for at least 6 months prior to screening. * Treated with diet and exercise and metformin daily, with or without other allowed oral antihyperglycaemia medications (OAMs), 3 months prior to screening. Allowed OAMs are dipeptidyl peptidase-4 inhibitors (DPP-IV) inhibitors, sodium/glucose cotransporter 2 (SGLT2) inhibitors, glinides, and sulfonylureas. * Have a HbA1c value at screening of: * 6.5% and ≤ 9.5 % if on metformin with or without SGLT2 inhibitors, or * 6% and ≤8.5% if on metformin in combination with allowed OAMs that require washout. * Have venous access sufficient to allow for blood sampling as per the protocol. * Have clinical laboratory test results within normal reference range for the population or investigative site or results with acceptable deviations that are judged to be not clinically significant by the investigator. * Have a body mass index (BMI) between 25 kilograms per meter squared (kg/m²) and 45 kg/m², both inclusive, at screening. * Have had a stable body weight that is less than 5% change during the 3-month period prior to screening. Exclusion Criteria: * Have Type 1 Diabetes Mellitus (T1DM) * Have had more than 1 episode of severe hypoglycaemia, as defined by the American Diabetes Association criteria, within 6 months before screening or a history of hypoglycaemia unawareness or poor recognition of hypoglycaemic symptoms; any participant that cannot communicate an …