AIM-WEIGHT: AI-Guided Microbiome-Targeted Nutritional Intervention for Weight Loss

Inclusion Criteria: * Age 18 to 65 years, inclusive. * Body mass index of 25.0 to 40.0 kg/m2 at screening. * No previous diagnosis of prediabetes or diabetes. * Glycated hemoglobin (HbA1c) below 5.7% at screening. * Fasting plasma glucose below 100 mg/dL at screening. * Stable body weight, defined as a self-reported absolute change of no more than 5% or 3 kg, whichever is smaller, during the 3 months before screening. * Willing and able to provide written informed consent. * Willing and able to comply with study visits, assigned supplement or placebo use, and the assessment schedule. * Willing to provide fasting venous blood and stool samples according to the study schedule. * Willing to receive standardized lifestyle counseling during the 24-week blinded intervention period. * No systemic antibiotic use within 8 weeks before randomization. * No probiotic, prebiotic, synbiotic, or postbiotic supplement use within 12 weeks before randomization. * If hypertension or dyslipidemia is present, antihypertensive or lipid-lowering treatment must have been initiated and the dose must have remained unchanged for at least 3 months before randomization, with no treatment change planned at the time of randomization. Exclusion Criteria: * Prediabetes or diabetes identified by medical history, HbA1c, or fasting plasma glucose. * Use of glucose-lowering medication, including metformin, a glucagon-like peptide-1 receptor agonist, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 co-agonist, a sodium-glucose cotransporter-2 inhibitor, a dipeptidyl peptidase-4 inhibitor, a sulfonylurea, insulin, or another antidiabetic agent. * Use of a glucagon-like peptide-1 receptor agonist or glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 co-agonist for any indication within 12 months before randomization. * Use of another anti-obesity medication, including orlistat, naltrexone/bupropion, or phentermine/topiramate, within 6 months before randomization. * Planned initiation during the 24-week study of a weight-loss medication, structured commercial weight-loss program, very-low-calorie diet, or bariatric procedure. * History of bariatric surgery. * History of gastrointestinal surgery other than appendectomy or uncomplicated cholecystectomy. * Active inflammatory bowel disease, celiac disease, microscopic colitis, chronic pancreatitis, malabsorption syndrome, or another chronic severe gastrointestinal disease likely to affect nutrient absorption or study adherence. * Acute gastroenteritis within 4 weeks before randomization. * Colonoscopy bowel preparation within 12 weeks before randomization. * Fecal microbiota transplantation within 12 months before randomization. * Active malignancy or malignancy treated within 6 months before screening, except adequately treated non-melanoma skin cancer. * Stage 3b to 5 chronic kidney disease, defined as an estimated glomerular filtration rate below 45 mL/min/1.73 m2. * Decompensated liver disease or Child-Pugh class B or C liver disease. * Alanine aminotransferase or aspartate aminotransferase greater than 3 times the upper limit of normal at screening, unless judged clinically insignificant and approved by the investigator. * Untreated overt thyroid disease, or initiation or dose modification of thyroid medication within 3 months before randomization. Stable treated hypothyroidism is permitted. * Use of systemic corticosteroids within 4 weeks before randomization. * Use of immunosuppressive medication or biologic or immunomodulatory therapy within 5 half-lives before randomization. * Pregnancy or lactation. * For participants of childbearing potential, unwillingness to use effective contraception during the 24-week blinded intervention period. * Severe psychiatric illness or cognitive impairment that, in the investigator's judgment, would impair informed consent, participant safety, or adherence to study procedures. * Active eating disorder, defined as at least 2 affirmative responses on the SCOFF screening questionnaire or a clinical diagnosis of anorexia nervosa, bulimia nervosa, or binge-eating disorder. * Heavy alcohol use or active substance use disorder. * Current use of a very-low-calorie diet, ketogenic diet, medically supervised weight-loss diet, or another highly restrictive diet that excludes major food groups. * Current cigarette smoking with a stated intention to attempt smoking cessation during the 24-week study, or initiation of nicotine-replacement or other smoking-cessation pharmacotherapy within 3 months before randomization. * Participation in another interventional clinical study within 30 days before screening. * Known hypersensitivity or clinically significant intolerance to any component of the active supplement or placebo. * Any condition that, in the investigator's judgment, would compromise participant safety, adherence, or study integrity.