The Study
Weight-loss dynamics with tirzepatide versus semaglutide
This study looked at what happened to people who were already taking one of two weight-loss drugs in real life. It found that people on tirzepatide tended to lose more weight than those on semaglutide, but it didn’t randomly assign people to the drugs — so we can’t be sure the drug itself caused the difference.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
This study looked at real patients using two popular weight-loss drugs to see which one helped people lose more weight and feel better.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 559 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Losing 15% or more of body weight can significantly improve health conditions like diabetes and high blood pressure — so tirzepatide’s higher success rate and fewer side effects could mean better real-world outcomes.
- 2Tirzepatide users lost 14.7% of their body weight on average vs.
- 310.8% for semaglutide users.
- 4Twice as many people lost 15% or more with tirzepatide (42.6% vs.
- 521.6%).
- 6Tirzepatide also caused fewer side effects like nausea and headaches.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PNAS Nexus
Year
2026
Authors
A. Venkatakrishnan, K. Murugadoss, V. Soundararajan
Related Content
Claims (6)
GLP-1 drugs cause different amounts of weight loss in different people.
In obese adults, tirzepatide is linked to fewer side effects such as nausea, vomiting, and headache than semaglutide, even though it leads to more weight loss.
Among obese adults, those treated with tirzepatide lost an average of 14.7% of their body weight over two years, while those treated with semaglutide lost an average of 10.8%. More people on tirzepatide lost at least 15% of their body weight compared to those on semaglutide.
In obese adults, tirzepatide leads to a monthly weight loss of 2.54% during the first six months, while semaglutide leads to a monthly weight loss of 2.18%.
In obese adults using tirzepatide or semaglutide for weight loss, women make up a larger share of those who lose at least 15% of their body weight than men.
In obese adults using tirzepatide or semaglutide for weight loss, 91.2% of those who lost at least 15% of their body weight are White, while 6.0% are Black and 1.6% are Hispanic.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.