Tirzepatide (Zepbound) will be a new option for obesity...now that it’s available in Canada to promote weight loss in adults.
Tirzepatide is the same ingredient in Mounjaro for type 2 diabetes. It works similarly to semaglutide (Wegovy), but it’s a dual agonist...at both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors.
These meds increase satiety and slow gastric emptying...which may lead to weight loss in people with or without diabetes.
When compared head-to-head, tirzepatide leads to an average of about 23 kg of weight loss compared to about 17 kg with semaglutide over about a year in patients without diabetes.
Think of these meds as more effective than other weight loss meds. For instance, liraglutide leads to roughly 5 kg of weight loss.
Also, data suggest that adding semaglutide 2.4 mg weekly for patients with overweight or obesity AND CV disease prevents 1 CV event for every 67 patients treated over about 3 years.
Results from a similar study with tirzepatide are due in 2027.
But it’s not all smooth sailing with these meds.
Tirzepatide or semaglutide commonly causes GI upset, especially during dose escalation. And both carry warnings for rare pancreatitis or gallbladder disease...and are linked to bowel obstruction.
Tirzepatide costs up to $820/month and semaglutide around $430. Many payers don’t cover these or require a prior auth...and high demand can cause shortages.
Plus patients may need to use these meds long term...since weight gain is common after stopping.
Continue to emphasize lifestyle changes first for weight loss.
Save weight loss meds as an option for patients with a BMI of 30 or more...or 27 or more plus a weight-related condition (diabetes, etc).
If trying a med to lose weight, tailor the selection based on weight loss goals, comorbidities, cost and access, etc.
If practical, consider tirzepatide for patients with severe obesity, since it may lead to more weight loss...or suggest semaglutide for patients with CV disease based on CV benefit.
Ensure these meds are titrated slowly to minimize GI effects.
For example, start tirzepatide at 2.5 mg weekly and increase by 2.5 mg every 4 weeks as tolerated...up to a max of 15 mg/week.
Counsel to expect modest GI upset...but to promptly report severe pain. It can be a red flag for gallbladder issues or pancreatitis.
Refer to our resource, Weight Loss Products, to compare other weight loss options...and our GLP-1 and GIP/GLP-1 Receptor Agonist Interactive Comparison Chart to review dosing, titration, and more.
- Aronne LJ, Horn DB, le Roux CW, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity. N Engl J Med. 2025 Jul 3;393(1):26-36.
- Grunvald E, Shah R, Hernaez R, et al; AGA Clinical Guidelines Committee. AGA Clinical Practice Guideline on Pharmacological Interventions for Adults With Obesity. Gastroenterology. 2022 Nov;163(5):1198-1225.
- American Diabetes Association Professional Practice Committee. 8. Obesity and Weight Management for the Prevention and Treatment of Type 2 Diabetes: Standards of Care in Diabetes-2024. Diabetes Care. 2024 Jan 1;47(Suppl 1):S145-S157.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022 Jul 21;387(3):205-216.
- Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021 Mar 18;384(11):989-1002.
- Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med. 2023 Dec 14;389(24):2221-2232.