# Is a GLP-1 Better Than Metformin? Nobody Has Run That Trial | This GLP Is a GLP-1 better than metformin? A 93-trial network puts metformin at OR 0.69 and GLP-1 agonists at 0.87, with overlapping intervals and no head-to-head trial. Publisher: This GLP Editorial Team Canonical: https://thisglp.com/research/is-a-glp1-better-than-metformin Updated: 2026-09-17 Published: 2026-09-16 [← Research](https://thisglp.com/research) Evidence # Is a GLP-1 Better Than Metformin? Nobody Has Run That Trial Across 93 trials, metformin had the largest reduction in cardiovascular events of any diabetes drug. It also had the least reliable evidence behind it. [This GLP Editorial Team](https://thisglp.com/about)September 20269 min readUpdated September 2026 Major cardiovascular events vs placebo · metformin · lower-quality evidence · SGLT2 inhibitors · tirzepatide · GLP-1 agonists · 1.0 · 93 studies — and four intervals that mostly overlap **Research, not medical advice.** This GLP is independent and educational. Nothing here is a substitute for individualized care from a licensed clinician, and reading it creates no doctor–patient relationship. Talk to your own provider before starting, stopping, or changing any medication, peptide, or therapy. See our [methodology](https://thisglp.com/methodology) and [terms](https://thisglp.com/terms). Nobody has run that trial. A network meta-analysis pooled 93 randomized trials of every approved type 2 diabetes class [\[1\]](https://thisglp.com/research/is-a-glp1-better-than-metformin#ref-1). Against placebo, metformin had the lowest odds ratio for major cardiovascular events. It was 0.69, 95% CI 0.53 to 0.89. GLP-1 agonists came in at 0.87, 95% CI 0.83 to 0.92. Tirzepatide and SGLT2 inhibitors were both 0.82. Those four intervals overlap. The authors grade the metformin evidence as lower quality. Every trial pooled here enrolled people with type 2 diabetes. That is also the population in [the kidney failure numbers needed to treat](https://thisglp.com/research/twenty-two-thirteen-seventeen). ## Key takeaways - A pairwise and network meta-analysis pooled 93 randomized trials of every approved class of type 2 diabetes drug. - Against placebo, metformin came in at OR 0.69 for major cardiovascular events, 95% CI 0.53 to 0.89. - SGLT2 inhibitors were 0.82, tirzepatide 0.82, and GLP-1 agonists 0.87. - The authors grade the metformin and pioglitazone evidence as lower quality, and the four intervals overlap heavily. - Sulfonylureas were the only class associated with more cardiovascular events. - A separate network of four trials found no difference in mortality or cardiovascular events between tirzepatide and dulaglutide. - The strongest single GLP-1 result, FLOW, was run against placebo at the 1.0 mg diabetes dose. ## What was pooled Ninety-three randomized trials of at least 40 weeks. [\[1\]](https://thisglp.com/research/is-a-glp1-better-than-metformin#ref-1) Each compared a diabetes medication against placebo or an active comparator. Cardiovascular events and deaths were formally adjudicated. Both pairwise and network methods were used. That lets drugs never tested against each other be compared indirectly. In the network against placebo, metformin came in at OR 0.69, 95% CI 0.53 to 0.89. SGLT2 inhibitors were 0.82, 95% CI 0.75 to 0.90. Tirzepatide was 0.82, 95% CI 0.72 to 0.93. GLP-1 agonists were 0.87, 95% CI 0.83 to 0.92. Insulin, DPP-4 inhibitors and sulfonylureas showed no significant effect on events. On all-cause mortality, tirzepatide came in at 0.72, 95% CI 0.64 to 0.82. SGLT2 inhibitors and GLP-1 agonists were both 0.85, 95% CI 0.80 to 0.91. In the pairwise analyses, sulfonylureas were associated with increased cardiovascular events. That was the only class moving the wrong way. Metformin is first and least certain, at once The authors attach lower quality of evidence to metformin and pioglitazone. It shows in the interval. Metformin runs 0.53 to 0.89; GLP-1 agonists run 0.83 to 0.92. Much of the metformin evidence comes from older trials run to different standards. A cheap generic has the largest point estimate and the least reliable one. Reporting either half alone misleads in opposite directions. ## Why this is not a ranking Read the four intervals, not the four point estimates. Metformin runs 0.53 to 0.89. SGLT2 inhibitors run 0.75 to 0.90. Tirzepatide runs 0.72 to 0.93. GLP-1 agonists run 0.83 to 0.92. Almost all of that overlaps. An analysis can produce an ordering it cannot defend. The ordering is the part that gets quoted. That is the same failure as [a pooled average that describes nobody](https://thisglp.com/research/glp1-weight-loss-pooled-average). These numbers support four classes reducing events and three reducing death. They do not support a first place. ## An indirect comparison is not a head-to-head The same limit shows up inside the GLP-1 class. A network of four randomized trials covering 14,348 participants compared tirzepatide with dulaglutide [\[2\]](https://thisglp.com/research/is-a-glp1-better-than-metformin#ref-2). One trial supplies 13,165 of them, or 91.8% of the evidence. Every published difference is measured against tirzepatide 5 mg, not against dulaglutide directly. No difference appeared in all-cause mortality or major cardiovascular events. The full reading is in [one trial that is 92% of a network](https://thisglp.com/research/is-tirzepatide-better-than-dulaglutide). ## Where the GLP-1 evidence is strongest It is strongest against placebo, not against metformin. FLOW randomized 3,533 people with type 2 diabetes and chronic kidney disease [\[3\]](https://thisglp.com/research/is-a-glp1-better-than-metformin#ref-3). The primary composite hazard ratio was 0.76, 95% CI 0.66 to 0.88. Major cardiovascular events were 0.82, 95% CI 0.68 to 0.98. All-cause death was 0.80, 95% CI 0.67 to 0.95. The dose was 1.0 mg weekly, which is the diabetes dose. The condition attached to all of it is set out in [the trial that stopped early](https://thisglp.com/research/semaglutide-and-kidney-disease). Several semaglutide trials in type 2 diabetes added it to metformin rather than replacing it. That pairing is covered in [taking metformin and Ozempic together](https://thisglp.com/research/can-you-take-metformin-and-ozempic-together). ## The population, and who is reading Everyone in these 93 trials had type 2 diabetes. A person buying a GLP-1 for weight loss without diabetes is not in this evidence. The cardiovascular case for that group rests on different trials in different populations. Metformin is not a weight-loss drug and is not sold as one. A table where it leads on cardiovascular events is a table about diabetes care. It is not a shopping list. The menu a seller does carry is counted in [the six obesity drugs on sale](https://thisglp.com/research/what-weight-loss-drugs-are-there-besides-ozempic). ## What a reader can use One rule. When a comparison puts an old generic near the top, read it as a statement about evidence. Old drugs have old trials. Old trials have wider intervals and looser methods. It cuts both ways. The generic’s apparent advantage should be discounted. The newer drug’s advantage over it has also not been demonstrated, because nobody ran that trial. And [an active comparator](https://thisglp.com/research/do-glp1-drugs-cause-gout) answers a narrower question than its sentence suggests. Almost nothing a seller publishes distinguishes the two, which [the disclosure scorecard](https://thisglp.com/tools/what-sellers-publish) counts. ## Frequently asked Is a GLP-1 better than metformin? No trial has compared them directly. In a 93-trial network against placebo, metformin's odds ratio for major cardiovascular events was 0.69 and the GLP-1 class was 0.87, with intervals that overlap and lower-quality evidence behind the metformin figure. Is metformin better than a GLP-1 for the heart? This analysis cannot show that. Metformin had the lowest point estimate, OR 0.69, with an interval from 0.53 to 0.89 that overlaps the others, and the authors grade its evidence as lower quality. Which drug reduced deaths most? Tirzepatide, at OR 0.72 with a 95% CI of 0.64 to 0.82, with SGLT2 inhibitors and GLP-1 agonists both at 0.85. Did anything make outcomes worse? Sulfonylureas were associated with increased cardiovascular events in the pairwise analyses — the only class that moved in that direction. Does this apply to someone without diabetes? No. Every trial pooled here enrolled people with type 2 diabetes, and the cardiovascular case for weight-loss buyers rests on separate trials. ## Sources 1. \[1\] Silverii GA, et al. (2026). Effect of Medications for Type 2 Diabetes on Cardiovascular Events and Mortality: A Comprehensive Pairwise and Network Meta-Analysis Diabetes, Obesity and Metabolism. [PMID 42530338](https://pubmed.ncbi.nlm.nih.gov/42530338/) 2. \[2\] Hageen AW, et al. (2026). Efficacy and Safety of Tirzepatide Versus Dulaglutide in Type 2 Diabetes With or Without Established Atherosclerotic Cardiovascular Disease: A Network Meta-Analysis of Randomized Clinical Trials Endocrinology, Diabetes & Metabolism. [PMID 42706739](https://pubmed.ncbi.nlm.nih.gov/42706739/) 3. \[3\] Perkovic V, et al. (2024). Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes New England Journal of Medicine. [PMID 38785209](https://pubmed.ncbi.nlm.nih.gov/38785209/) ## Where to get it ### Best GLP-1 injections Every injectable seller we can verify, with the price each one publishes and an honest read of what the trials measured. [Compare providers →](https://thisglp.com/best/compounded-semaglutide) ## More in Evidence - [ 150 minutes · Weekly activity goal · 2 days · Muscle strengthening · Adapt · Symptoms and ability ### Exercise on Ozempic: Building Strength Without Ignoring Symptoms ](https://thisglp.com/research/exercise-on-ozempic) - [ STEP 1, semaglutide 2.4 mg vs placebo, % change at 68 weeks · LDL cholesterol · −2.5% vs +1.3% · Total cholesterol · −3.3% vs +0.1% · HDL cholesterol · +5.2% vs +1.4% · Triglycerides · −21.9% vs −7.3% · Wegovy label, Table 13. Adults without diabetes. Ozempic doses are lower. ### Does Ozempic Lower Cholesterol? What the Lipid Results in the Trials Show ](https://thisglp.com/research/does-ozempic-lower-cholesterol) - [ Where the insulin reduction came from, units per day · week 4 · 13.4 total · week 26 · 21.9 · the drug itself · the weight loss · The drug’s own contribution barely moved: 11.1 then 11.4. · Everything added between weeks 4 and 26 came from weight. ### Does Semaglutide Help Type 1 Diabetes? What Two Small Trials Found ](https://thisglp.com/research/semaglutide-in-type-1-diabetes)