Mechanisms of Weight Loss: Tirzepatide vs Semaglutide
Key facts
- Where
- Hamilton, CanadaSee the site
- Phase
- Phase 4
Could this be for you?
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 60 years old?
Source: NCT07900074, who can take part
Where in Canada
- McMaster UniversityHamilton, CanadaTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- McMaster University
- Trial code
- NCT07900074
- Record updated
- 28 October 2026
- Original description
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:Read full original descriptionShow less
Mechanisms of Weight Loss Due to Dual GIP GLP-1 Receptor Agonism With Tirzepatide Compared to Semaglutide: A Randomized Controlled Trial
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)
Inclusion: Age 18-60 years; Body mass index (BMI) >30 kg/m2; Stable body weight (<5kg change in the 3 months prior to screening).
Exclusion: 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; Currently pregnant/breastfeeding, previous pregnancy within the last 6 months, or unwillingness to use contraception for 3 months; Participation in any intervention clinical study within 90 days before screening; History of type 1 or type 2 diabetes or current diagnosis; History of pancreatitis; Personal or family history of medullary thyroid cancer or multiple endocrine neoplasia 2; 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; History of cardiac conditions that precludes exercise; History of eating disorder within the last year; Glucose-lowering or weight loss drugs in the last 3 months or planned in the next 3 months; Known liver disease other than non-alcoholic fatty liver disease, or ALT >3x ULN; Estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2; Intake of standard alcoholic drinks more than 21/week for men, or 14/week for women; 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.