A Study of Retatrutide (LY3437943) in Participants Without Type 2 Diabetes Who Have Obesity or Overweight

The purpose of this study is to investigate the efficacy and safety of different retatrutide dose escalation schemes in participants without type 2 diabetes who have obesity or overweight. Participation in the study will last about 113 weeks.

Inclusion Criteria: * Have a Body Mass Index (BMI) at screening * ≥ 30 kilogram per square meter (kg/m2) OR * ≥ 27 kg/m2 with presence of at least one of the following weight-related conditions at screening: high blood pressure, abnormal levels of lipid, obstructive sleep apnea, heart disease * Have at least one unsuccessful attempt to lose weight by dieting Exclusion Criteria: * Have a self-reported change in body weight \>5 kilograms (kg) (11 pounds) within 90 days before screening * Have a prior or planned surgical treatment for obesity * Have type 1 diabetes or type 2 diabetes * Have a family or personal history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN-2) * Have had within the past 90 days before screening: * heart attack * stroke * hospitalization for unstable angina or heart failure * Have New York Heart Association Functional Classification Class IV congestive heart failure * Have a history of chronic or acute pancreatitis * Have taken weight loss drugs, including over-the counter medications within 90 days prior to screening