Research · Evidence roundup

2026 Semaglutide Trials: SELECT, FLOW, SOUL

By Erik Jones · Oct 20, 2026 · 6 min read

If you live with type 2 diabetes and take semaglutide (sold as Ozempic, Wegovy, or Rybelsus), you may have heard this drug now “protects your heart and kidneys.” Three big trials are behind that claim: SELECT, FLOW, and SOUL. Here is what each one actually tested, and what it did not.

FLOW: kidney protection, tested in people with type 2 diabetes

FLOW enrolled 3,533 people who had type 2 diabetes and chronic kidney disease, the kind marked by protein leaking into the urine (called albuminuria). Everyone in the trial was already on a standard kidney-protecting medicine. Half were then given semaglutide, 1 mg by injection once a week; the other half got a placebo (a shot with no drug in it).

The trial tracked a combined outcome: kidney failure, a large drop in kidney function (at least half), or death related to the kidneys or the heart. People on semaglutide reached that combined endpoint 24% less often than people on placebo. In the language researchers use, the hazard ratio was 0.76, with a 95% confidence interval of 0.66 to 0.88 — meaning the true effect is very likely somewhere in that range, not just a lucky result.

This is the clearest of the three results for someone with type 2 diabetes and existing kidney disease, because the trial was built around exactly that person.

SOUL: a daily pill, tested in people with type 2 diabetes

SOUL tested the pill form of semaglutide (oral semaglutide, up to 14 mg a day) in 9,650 people with type 2 diabetes who already had heart disease, kidney disease, or both. Half took the pill, half took a placebo pill, for an average of about four years.

The trial counted a combined heart outcome: death from a cardiovascular cause, a non-fatal heart attack, or a non-fatal stroke. That outcome happened to 12.0% of people on semaglutide versus 13.8% on placebo, a 14% relative reduction (hazard ratio 0.86, 95% CI 0.77 to 0.96). Looking at the pieces separately, non-fatal heart attacks dropped by roughly a quarter, but the drop in strokes and in cardiovascular deaths on their own was not large enough to rule out chance. The heart attack reduction is doing most of the work in this result.

SELECT: a different population — read this part carefully

SELECT is the trial most often quoted alongside the other two, and it is the one that needs the biggest caveat. SELECT enrolled 17,604 people with overweight or obesity and existing heart disease who did not have diabetes. Participants took semaglutide 2.4 mg by weekly injection (the dose sold as Wegovy) or a placebo, for an average of about three and a half years.

The combined heart outcome, measured the same way as in SOUL, happened 20% less often in the semaglutide group (hazard ratio 0.80, 95% CI 0.72 to 0.90).

That is a real, well-measured result. But SELECT does not show what semaglutide does for a person who actually has type 2 diabetes, because people with diabetes were excluded from the trial on purpose. It tells you what happens in people without diabetes who have obesity and heart disease, and that is a different group than the one reading this. A 2026 European Society of Cardiology guideline summary treats SELECT’s cardiovascular result and FLOW’s kidney result as established findings worth building guidance around, which tells you these are taken seriously, not that SELECT was run in people with diabetes.

Not medical advice. Educational summary of published research. Last reviewed Oct 20, 2026.