Efficacy and Safety of Tirzepatide Once Weekly Versus Placebo in Participants Who Are Either Obese or Overweight With Weight-Related Comorbidities (SURMOUNT-1)

Inclusion Criteria: * BMI ≥30 kg/m², OR BMI ≥27 kg/m² with ≥1 weight-related comorbidity (e.g., hypertension, dyslipidemia, obstructive sleep apnea, cardiovascular disease) * History of at least one unsuccessful dietary effort to lose weight (self-reported) * Investigator judges participant capable and willing to self-inject (or have assistance), follow lifestyle advice, maintain a diary, and complete questionnaires * Age ≥18 years * Meets protocol contraception/pregnancy criteria (as applicable) and provides written informed consent Exclusion Criteria: * Type 1 or type 2 diabetes, history of ketoacidosis/hyperosmolar state, or screening labs diagnostic of diabetes * Recent significant weight change (\>5 kg within 3 months prior to screening) * Prior/planned bariatric surgery; recent/ongoing endoscopic or device-based obesity therapies * Severe renal impairment (eGFR \<30 mL/min/1.73 m²) * Clinically significant gastric emptying abnormality or chronic use of drugs that directly affect GI motility * History of chronic or acute pancreatitis * Clinically significant thyroid abnormalities at screening (e.g., TSH outside protocol range) or anticipated need to initiate thyroid replacement during study * Obesity due to other endocrinologic disorders (e.g., Cushing syndrome) or monogenic/syndromic obesity (e.g., MC4R deficiency, Prader-Willi syndrome) * Significant unstable major depressive disorder/severe psychiatric disorder, lifetime suicide attempt, or concerning suicidality screening (PHQ-9/C-SSRS criteria) * Uncontrolled hypertension; recent major cardiovascular events; NYHA class IV heart failure * Active or significant liver disease or certain elevated liver tests at screening (per protocol thresholds) * Elevated calcitonin above protocol thresholds; personal/family history of medullary thyroid carcinoma or MEN2 * Active/untreated malignancy or remission \<5 years (with specified exceptions) * Any other condition contraindicating GLP-1 receptor agonist therapy