A Study to Investigate the Safety and Efficacy of TE-8105 in Overweight or Obesity Participants

Inclusion Criteria: * Able to understand the full nature, purpose, and risks of the study and provide written informed consent before starting study procedures. * Body Mass Index (BMI) ≥25 and ≤34.9 kg/m², OR * BMI ≥25 and ≤34.9 kg/m² with at least one weight-related condition: high blood pressure (hypertension), high cholesterol or triglycerides (dyslipidemia), cardiovascular disease, or type 2 diabetes mellitus. * Stable body weight (less than 5% change in weight in either direction) during the screening period. * Medically healthy overall (apart from overweight or obesity) as determined by medical history, physical examination, vital signs, ECG, and routine laboratory tests without clinically significant abnormalities. * Female participants: Must be unable to become pregnant (postmenopausal for at least 12 months or surgically sterilized at least 6 weeks prior to screening), OR If able to become pregnant: must have negative pregnancy tests at screening and before randomization, agree not to attempt pregnancy or donate eggs, and agree to use a condom combined with a highly effective method of birth control from consent until at least 60 days after the last study dose (unless practicing complete abstinence or in a same-sex relationship). * Male participants: Must agree not to donate sperm from consent until at least 120 days after the last study dose. If sexually active with a female partner who can become pregnant, must agree to use a condom combined with highly effective birth control until at least 120 days after the last study dose. If sexually active with a female partner who cannot become pregnant or a same-sex partner, must agree to use a condom until at least 30 days after the last study dose. * Have suitable veins for routine blood draws. Exclusion Criteria: * An abnormal clinical laboratory test value specified in the protocol. * Previous weight-loss surgery or procedures (e.g., gastric bypass, sleeve gastrectomy, gastric balloon, or intestinal sleeve) within 6 months prior to screening, or planned during the study. * Participation in organized weight-loss programs (e.g., WeightWatchers, Jenny Craig) or meal replacement plans within 30 days prior to screening or planned during the study. * Self-reported weight change of more than 5% in the 6 months prior to randomization or more than 10% in the 12 months prior to screening. * Exposure to any GLP-1 receptor agonist medications within 3 months prior to screening, history of allergic reactions to GLP-1 medications, or lingering effects/rebound weight gain from past GLP-1 treatments. * Use of prescription or over-the-counter medications intended to promote weight loss or that cause weight gain within 3 months prior to randomization. * Use of any diabetes medication other than metformin (e.g., insulin use is excluded). * Diagnosis of Type 1 diabetes, history of diabetic ketoacidosis, or hyperosmolar coma. * Obesity caused by other hormonal disorders (e.g., Cushing syndrome) or rare genetic conditions (e.g., Prader-Willi syndrome). * History or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia type 2 (MEN 2). * Uncontrolled thyroid disease, unless on a stable thyroid replacement dose for at least 3 months, or subclinical thyroid conditions that may require new treatment during the study. * Severe kidney impairment (eGFR \<30 mL/min/1.73 m² or creatinine clearance \<60 mL/min). * Significant liver disease, acute/chronic hepatitis, elevated liver enzymes (ALT \> 3.0x upper limit of normal, ALP \>1.5x upper limit of normal, or bilirubin \>1.2x upper limit of normal), or fasting triglycerides \> 500 mg/dL. * History of chronic pancreatitis or unexplained acute pancreatitis. * Gastrointestinal disorders (such as severe acid reflux or delayed stomach emptying) that could interfere with drug absorption or study participation. * Severe or uncontrolled heart conditions within 3 months prior to randomization (e.g., heart attack, stroke, unstable angina, or heart failure hospitalization), or Class IV severe heart failure. * History of irregular heart rhythms or risk factors for long QT syndrome (Torsade de Pointes). * Active cancer or history of cancer within the last 10 years (except fully removed non-melanoma skin cancer). * Positive screening test for HIV, Hepatitis B, or Hepatitis C. * Active infection requiring systemically absorbed antibiotics, antivirals, or antifungals within 10 days before the first dose. * Active or unstable major depression or severe psychiatric disorders (such as schizophrenia or bipolar disorder) within the past 2 years. (Participants with stable depression or generalized anxiety on stable treatment may be eligible). * Any lifetime history of suicide attempts, or active suicidal thoughts/self-harm ideation within 2 weeks prior to or during screening. * History of alcohol abuse within 1 year, or regular consumption of more than 2 standard drinks per day (14 drinks per week). * Positive drug screen for drugs of abuse or positive alcohol breath test at screening or before the first dose. * Heavy smoking or nicotine use (≥6 cigarettes, cigars, vapes, or nicotine equivalents per day). * Unwillingness to refrain from starting new intense exercise programs (including weightlifting) from 7 days prior to Day 1 through 28 days after the final dose. * Unwillingness to follow dietitian advice, maintain study diaries, or refrain from using prohibited medications. * Females who are pregnant, breastfeeding, or planning to breastfeed. * Skin conditions (such as severe sunburn, deep scar tissue, large tattoos, or open sores) at potential injection sites that would interfere with dosing or site assessments. * Blood or plasma donation within 30 days, major blood loss (\>500 mL) within 30 days, or blood transfusion within 1 year prior to first dose. * Participation in another clinical trial testing an investigational drug or device within 30 days prior to screening. * Any active, serious medical condition with an estimated life expectancy of less than 2 years, or any condition that in the investigator's judgment makes participation unsafe or non-compliance likely.