Semaglutide CV edge over tirzepatide

A systematic review and meta-analysis published in Diabetology & Metabolic Syndrome on 18 June 2026 pooled 47 randomised controlled trials and 59,352 participants to compare the cardiovascular effects of semaglutide and tirzepatide in people with type 2 diabetes or obesity^[1]. The headline finding: semaglutide showed statistically significant reductions in major adverse cardiovascular events, cardiovascular death, myocardial infarction, and heart failure hospitalisation. Tirzepatide did not reach significance on most of those endpoints.

What the review measured

The authors (Zhou et al., Chongqing Medical University) searched PubMed, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov through November 2024. They registered the protocol on PROSPERO (CRD420251008819) and reported risk ratios with 95% confidence intervals for five cardiovascular endpoints: major adverse cardiovascular events (MACE), cardiovascular death, myocardial infarction, stroke, and heart failure hospitalisation^[1].

Forty-seven trials is a large pool for this specific question. The breadth matters because earlier cardiovascular assessments for these two drugs rested on a smaller number of dedicated outcomes trials, primarily SELECT for semaglutide and the ongoing SURPASS-CVOT for tirzepatide.

Semaglutide cardiovascular results

Across the included trials, semaglutide was associated with a 29% reduction in MACE (RR 0.71, 95% CI 0.60 to 0.84, p < 0.001), a 19% reduction in cardiovascular death (RR 0.81, 95% CI 0.72 to 0.93, p = 0.002), a 30% reduction in myocardial infarction (RR 0.70, 95% CI 0.61 to 0.80, p < 0.001), and a 40% reduction in heart failure hospitalisation (RR 0.60, 95% CI 0.41 to 0.87, p = 0.007)^[1].

Stroke trended lower but did not reach statistical significance (RR 0.86, 95% CI 0.73 to 1.00, p = 0.056). These results are broadly consistent with the SELECT trial, which enrolled 17,604 adults with overweight or obesity and established cardiovascular disease but without diabetes and reported a 20% reduction in MACE (HR 0.80, 95% CI 0.72 to 0.90, p < 0.001)^[2]. The meta-analysis extends that signal by including trial populations with type 2 diabetes as well.

Tirzepatide cardiovascular results

Tirzepatide showed a point estimate favouring cardiovascular benefit, but the confidence intervals were wide and most endpoints did not reach statistical significance. MACE was not significantly reduced (RR 0.79, 95% CI 0.54 to 1.17, p = 0.245). The one exception was myocardial infarction, which reached borderline significance (RR 0.63, 95% CI 0.40 to 1.00, p = 0.049). Cardiovascular death, heart failure hospitalisation, and stroke were not statistically significant^[1].

The authors attribute this gap to the evidence base rather than a pharmacological difference. The dedicated cardiovascular outcomes trial for tirzepatide (SURPASS-CVOT) has not yet reported results. Without a large, purpose-built trial driving the pooled estimates, the confidence intervals remain too wide to draw firm conclusions.

What this does and does not tell us

The review confirms what the SELECT trial already demonstrated for semaglutide: a consistent, statistically significant cardiovascular benefit across multiple endpoints. It does not prove that tirzepatide lacks cardiovascular benefit. The point estimates for tirzepatide trend in the same protective direction as semaglutide, but the trial base is smaller and no single large outcomes trial anchors the pooled analysis.

Clinicians making treatment decisions today have cardiovascular evidence for semaglutide and a plausible but unconfirmed signal for tirzepatide. The authors describe semaglutide as showing "a more consistent signal of cardiovascular benefit across the included trials, whereas cardiovascular outcome evidence for tirzepatide remained limited and uncertain." That characterisation is fair given the data, but it is a statement about the evidence base, not necessarily the drug.

Limitations to note

The review's search window closed in November 2024, meaning any trials published or reported after that date are not included. The 47 trials vary in design, duration, population, and primary endpoint. Not all were designed to measure cardiovascular outcomes as a primary objective; many were diabetes or obesity efficacy trials that collected cardiovascular events as secondary or safety endpoints. Heterogeneity in trial design is a standard limitation of meta-analyses in this space. The study was funded by China's National Natural Science Foundation, and the authors declared no competing interests.

Anyone reading this review alongside the ACP living meta-analysis of obesity drugs (Damen et al., Annals of Internal Medicine, June 2026) will see a consistent theme: semaglutide is the only drug in the GLP-1 class with strong cardiovascular outcomes data, and the field is waiting on outcomes trials for tirzepatide and retatrutide to fill that gap.