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RECRUITING

NCT07900074

PHASE4

Mechanisms of Weight Loss: Tirzepatide vs Semaglutide

Sponsor: McMaster University

View on ClinicalTrials.gov

Summary

The goal of this clinical trial is to determine if there are differences in the effect of 12 weeks of tirzepatide versus semaglutide on energy balance in adults with obesity and without known diabetes. The main questions it aims to answer are: \- Does tirzepatide have a greater effect on energy expenditure or energy extraction than semaglutide? Participants will: * Take tirzepatide or semaglutide once weekly for 12 weeks * Undergo identical baseline and week 12 study visits (including 24-hour whole room indirect calorimeter testing, MRI scan, body composition, 3-day meal plan and stool collection)

Official title: Mechanisms of Weight Loss Due to Dual GIP GLP-1 Receptor Agonism With Tirzepatide Compared to Semaglutide: A Randomized Controlled Trial

Key Details

Gender

All

Age Range

18 Years - 60 Years

Study Type

INTERVENTIONAL

Enrollment

Start Date

2026-10-31

Completion Date

2029-12-31

Last Updated

2026-10-28

Healthy Volunteers

Conditions

Obesity (Disorder)

Interventions

DRUG

Tirzepatide

This group will take tirzepatide once weekly for 12 weeks. Participants will be started at 2.5 mg and increase by one dose level every 4 weeks, if tolerated (allowing up to 3 dose levels over 12 weeks), to a maximum dose of 7.5 mg. Dose levels are 2.5 mg, 5 mg, 7.5 mg.

DRUG

Semaglutide

This group will take semaglutide once weekly for 12 weeks. Participants will be started at 0.25 mg and increase by one dose level every 4 weeks, if tolerated (allowing up to 3 dose levels over 12 weeks), to a maximum dose of 1 mg. Dose levels are 0.25 mg, 0.5 mg, 1 mg.

Inclusion Criteria: * Age 18-60 years * Body mass index (BMI) \>30 kg/m2 * Stable body weight (\<5kg change in the 3 months prior to screening) Exclusion Criteria: * History of type 1 or type 2 diabetes or current diagnosis * Glucose-lowering or weight loss drugs in the last 3 months or planned in the next 3 months * Prior or planned bariatric surgery or planned low calorie meal program in the next 3 months * Known clinically significant gastric emptying abnormality (for example, severe gastroparesis or gastric outlet obstruction) or chronic GI symptoms (nausea, vomiting, diarrhea, constipation, bloating or unexplained abdominal pain) or chronically take drugs that directly affect GI motility * Known liver disease other than non-alcoholic fatty liver disease, or ALT \>3x ULN * Intake of standard alcoholic drinks more than 21/week for men, or 14/week for women * Estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2 * History of pancreatitis * Personal or family history of medullary thyroid cancer or multiple endocrine neoplasia 2 * Currently pregnant/breastfeeding, previous pregnancy within the last 6 months, or unwillingness to use contraception for 3 months * Other medications, allergies or comorbidities that, in the opinion of the investigator could interfere with study medication or study measures (e.g., catecholamine medications) or current medication use that has been unstable in the past 8 weeks or expected to change within the next 3 months * Claustrophobia precluding a 24 hour stay in a whole room calorimeter or MRI scan * Inability to undergo MRI (weight \>250 kg, incompatible implanted device, e.g., pacemaker) * Use of cannabis or its related products (d-9-THC, CBD, d-8-THC, and cannabinol) in the past three months * Use of nicotine/tobacco that has been unstable in the past 8 weeks or expected to change within the next 3 months (exclusion from MRI visit ONLY) * Known monogenic, syndromic hypothalamic causes of obesity * Not able to communicate in English * History of cardiac conditions that precludes exercise * Participation in any intervention clinical study within 90 days before screening * History of eating disorder within the last year

Locations (1)

McMaster University

Hamilton, Ontario, Canada