The aim of this trial is to investigate the safety, tolerability, pharmacokinetics, and efficacy of THDBH120 injection in participants with obesity. This study includes three multiple-ascending dose cohorts.

Inclusion Criteria:

• Age between 18 and 65 years (inclusive), male or female;
• Body mass index (BMI) ≥ 28 kg/m²;
• Diet and exercise control for at least 3 months before screening visit, and less than 5% self-reported change within the last 3 months.

Exclusion Criteria:

• Type 1 diabetes, type 2 diabetes, gestational diabetes, or other types of diabetes;
• History of obesity attributable to endocrine diseases, monogenic mutations, or drug-induced causes, such as hypothalamic obesity, pituitary obesity, hypothyroid obesity, Cushing's syndrome, insulinoma, acromegaly, or hypogonadism; or weight gain resulting from increased non-fat mass (e.g., edema);
• Presence of uncontrolled hypertension at screening: systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥100 mmHg;
• Prolonged QTcF interval on 12-lead ECG at screening (QTcF≥450 ms for males, >470 ms for females), PR interval >200 ms, or the presence of long QT syndrome, second- or third-degree atrioventricular block, left or right bundle branch block, Wolff-Parkinson-White syndrome, or any other clinically significant arrhythmias (except sinus arrhythmia).