Written by
Jessica Guht
Medical & Health Writer | Wellness Enthusiast | MEng in Biomedical Engineering
Jessica is a medical writer with an unquenched thirst to discover something new. She believes that medical content should be universally accessible and strives to write content that everyone, no matter their background, can understand. Credentials: MEng in Biomedical Engineering from Rutgers University.
How do Tirzepatide and Semaglutide Aid Weight Loss?
While both tirzepatide and semaglutide help you to eat less, they do so through slightly different mechanisms.
Tirzepatide is a glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist that mimics both the GIP and GLP-1 hormones. Both of these hormones trigger insulin production in your body, which then sends fullness signals to your brain.
While tirzepatide mimics both hormones, semaglutide is only a GLP-1 receptor agonist, so it only mimics one hormone.
The ability to mimic two hormones in your body may be why tirzepatide has been shown to result in greater weight loss than semaglutide. However, it is worth noting that in these studies, the dose of tirzepatide was higher, which may be why the tirzepatide group had greater weight loss. Still, the studies show that both medications can aid weight loss.
Dosing Guide for Semaglutide and Tirzepatide
Dosages vary between the two medications since the drugs work differently.
Both follow a gradual dosing. Tirzepatide starts at 2.5 mg once per week and, starting at week 5, increases to 5 mg once a week, with the dose increasing by 2.5 mg until the maintenance dose is reached. With semaglutide, the starting dose is 0.25 mg once a week and, beginning in week 5, it increases by 0.25 mg or 0.5 mg until the maintenance dose is reached.
Side Effects of Semaglutide and Tirzepatide
Both medications have similar side effects, which can include:
- Upset stomach
- Constipation or diarrhea
- Nausea or vomiting
- Fatigue
- Low blood sugar
In severe cases, the following side effects may occur with either medication:
- Pancreatitis
- Vision changes
- Gallbladder issues
- Kidney failure
- Allergic reactions
Furthermore, both semaglutide and tirzepatide have boxed warnings about the risk of thyroid C-cell tumors.
Can You Switch From Semaglutide to Tirzepatide?
Evidence suggests that it is generally safe to switch from semaglutide to tirzepatide, and if semaglutide alone is not helping you lose weight, switching to tirzepatide may give your body the boost it needs to see genuine results. However, it’s always best to talk to a doctor before switching medications.
Tirzepatide vs. Semaglutide: Final Takeaways
Tirzepatide and semaglutide are both type 2 diabetes drugs that may also be prescribed to aid weight loss. They are both administered as weekly injections, although their dosages vary. Additionally, while both are GLP-1 receptor agonists, tirzepatide also mimics the GIP hormone, which may be why those who take tirzepatide see greater weight loss.
As with many medications, there are side effects to be aware of for both tirzepatide and semaglutide, including a range of severe side effects. Always discuss the risk of side effects with your doctor before beginning medication to ensure that the potential weight loss is worthwhile.
Interested in trying either of these weight loss drugs? YOURx can help you get them.
References
Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Arihiro Kiyosue, Zhang, S., Liu, B., Bunck, M. C., & Stefanski, A. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, 387(3), 205–216. https://doi.org/10.1056/nejmoa2206038
Kommu S, Whitfield P. Semaglutide. [Updated 2024 Feb 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK603723/
Rodriguez, P. J., Goodwin Cartwright, B. M., Gratzl, S., Brar, R., Baker, C., Gluckman, T. J., & Stucky, N. L. (2024). Semaglutide vs Tirzepatide for Weight Loss in Adults With Overweight or Obesity. JAMA Internal Medicine, 184(9), 1056. https://doi.org/10.1001/jamainternmed.2024.2525
