A safety review of the two leading peptide-based obesity drugs found that tirzepatide (dual GIP/GLP-1 agonist) has fewer reported side effects than semaglutide, with additional benefits for bone formation and kidney protection.
Fewer side effectsTirzepatide showed fewer reported adverse effects than semaglutide, plus additional bone and kidney protective properties from dual-receptor peptide agonism
What the researchers found
Both semaglutide and tirzepatide share common side effects including gastrointestinal issues (nausea, vomiting, pancreatitis, diarrhea), bone remodeling changes, kidney disorders, and thyroid concerns. However, tirzepatide was preferred over semaglutide based on fewer reported side effects overall.
Tirzepatide showed additional advantages: it promoted bone formation (a protective effect) and demonstrated renal protective effects, specifically in decreasing albuminuria and slowing estimated glomerular filtration rate (eGFR) decline — markers of kidney disease progression. These advantages may be related to the additional GIP receptor activation that tirzepatide provides beyond GLP-1 agonism alone.
Why it matters
With tens of millions of patients prescribed these peptide drugs globally — and many expected to take them for years or indefinitely — understanding their comparative long-term safety is critical. This review provides clinicians with a side-by-side comparison to inform drug selection, particularly for patients with pre-existing bone, kidney, or thyroid conditions who may benefit from the additional protective properties of tirzepatide's dual-receptor mechanism.
How the study worked
Narrative review examining post-marketing safety data, clinical trial reports, and published literature on the long-term tolerability and side effect profiles of semaglutide and tirzepatide in obesity management.
What this study cannot tell us
As a narrative review, the comparison is qualitative rather than based on a formal meta-analysis. Post-marketing safety data can be subject to reporting bias. The relative novelty of tirzepatide (approved more recently than semaglutide) means less long-term safety data is available. Head-to-head randomized safety trials would provide more definitive comparative data. Different dosing ranges and patient populations across studies complicate direct comparison.
How to read the evidence
This is a narrative review synthesizing post-marketing safety data and clinical trial results. It provides a useful clinical overview but is not a systematic review or meta-analysis, so the comparative conclusions are qualitative.
When this study was published
Published in 2025, this review captures the latest post-marketing safety data for both drugs, making it relevant to current prescribing decisions as these peptide medications reach widespread clinical use.
The bigger picture
As GLP-1 and dual-agonist peptide drugs become foundational treatments for metabolic disease, their safety profiles will increasingly influence market share and clinical guidelines. This review supports the emerging view that dual GIP/GLP-1 agonism (tirzepatide) may provide not only superior efficacy but also a more favorable safety profile compared to GLP-1-only agonism (semaglutide). The finding that GIP receptor activation adds bone and kidney protective effects could reshape how clinicians choose between these drugs.
Questions still open
- Will tirzepatide's safety advantage hold up as more long-term post-marketing data accumulates?
- Is the bone-protective effect of tirzepatide clinically meaningful enough to reduce fracture risk in patients on long-term therapy?
- Should pre-existing kidney disease or osteoporosis risk factor into the choice between semaglutide and tirzepatide?
Common questions
Which is safer — semaglutide or tirzepatide?
What's the difference between how semaglutide and tirzepatide work?
Read the original research
Comparative safety and side effects of semaglutide and tirzepatide: Implications for clinical decision-making in obesity management.
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 193, 118731
Citation
Fahim, Sally A; Attia, Yasmin M; Messiha, Albeir; Nabawy, Ashrakat Y; Refaat, Fady; El-Maadawy, Walaa H. (2025). Comparative safety and side effects of semaglutide and tirzepatide: Implications for clinical decision-making in obesity management.. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 193, 118731. https://doi.org/10.1016/j.biopha.2025.118731