A large real-world comparison found no meaningful differences in severe gastrointestinal adverse events between dulaglutide, semaglutide, and tirzepatide in type 2 diabetes patients.
No significant differenceAll three GLP-1 drugs showed similar rates of serious GI events including pancreatitis, biliary disease, and bowel obstruction
What the researchers found
No significant differences in composite GI adverse events were found: semaglutide vs dulaglutide HR 0.96 (0.87-1.06), tirzepatide vs dulaglutide HR 0.96 (0.77-1.20), tirzepatide vs semaglutide HR 1.07 (0.90-1.26).
Why it matters
Patients and clinicians often worry about GI side effects when choosing between GLP-1 drugs. This evidence showing equivalent safety profiles allows treatment decisions to be based on other factors like efficacy and cost.
How the study worked
New-user, active-comparator cohort study with 1:1 propensity score matching across three pairwise comparisons using population-based data from January 2019 to August 2024.
What this study cannot tell us
Possible residual confounding by glycemic control and BMI. Observational design. May not capture milder GI symptoms that don't result in medical encounters or diagnoses.
How to read the evidence
Large population-based cohort study with propensity-score matching and active comparators. Strong real-world evidence, though observational design limits causal inference.
When this study was published
Published in 2025 using data through August 2024, reflecting current prescribing patterns.
The bigger picture
As the GLP-1 drug market expands with multiple options, head-to-head safety data helps clinicians and patients make informed choices. This study provides reassurance that switching between these peptide drugs doesn't meaningfully change GI risk.
Questions still open
- Do dose-dependent differences in GI safety emerge at higher titration levels of each drug?
- How does GI safety compare when these drugs are used for obesity (higher doses) rather than diabetes?
- Are there subpopulations (e.g., those with prior GI conditions) where safety differences might emerge?
Common questions
Which GLP-1 drug has the fewest stomach side effects?
Should I worry about stomach problems when switching between GLP-1 medications?
Read the original research
Comparative Gastrointestinal Safety of Dulaglutide, Semaglutide, and Tirzepatide in Adults With Type 2 Diabetes.
Annals of internal medicine, 179(1), 1-11
Citation
Crisafulli, Salvatore; Alkabbani, Wajd; Paik, Julie M; Bykov, Katsiaryna; Tavakkoli, Ali; Glynn, Robert J; Htoo, Phyo T; Yu, Elaine W; Trifirò, Gianluca; Wexler, Deborah J; Patorno, Elisabetta. (2026). Comparative Gastrointestinal Safety of Dulaglutide, Semaglutide, and Tirzepatide in Adults With Type 2 Diabetes.. Annals of internal medicine, 179(1), 1-11. https://doi.org/10.7326/ANNALS-25-01724