Weight-loss drugs tirzepatide vs. semaglutide in adults with obesity

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This 12-week, single-centre randomized trial compares tirzepatide to semaglutide in adults with obesity who do not have diagnosed diabetes. Participants undergo baseline and end-of-study testing, including a 23-hour whole-room calorimeter to measure energy expenditure, MRI for brown fat activity, body composition analyses, and a 3-day meal plan with stool collection to assess energy intake and gut factors. The study aims to determine differences in energy expenditure, energy extraction from food, appetite, and related metabolic parameters between the two drugs. Participants self-administer weekly injections, with dose escalation every four weeks if tolerated, under close monitoring at McMaster University in Hamilton, Ontario.

Why it matters

Who can join: the full rules

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

Where it's running

• McMaster University
  Hamilton, Ontario, Canada Recruiting

Study contacts

• Principal investigator: Zubin Punthakee, MD, MSc — McMaster University
• Study coordinator: Autumn Lawrence, MSc
• Email: joule3@mcmaster.ca
• Phone: 905-525-9140

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.