Semaglutide research in hearts and kidneys
A change in body size is visible. These trials counted events that a silhouette could never show.
SUSTAIN-6 heart outcomes
Semaglutide research extends well beyond a tissue scan. SUSTAIN-6 enrolled 3,297 people with type 2 diabetes at high cardiovascular risk. The primary combined outcome included cardiovascular death, nonfatal heart attack and nonfatal stroke. With weekly subcutaneous semaglutide, its hazard ratio was 0.74, with a 95% confidence interval of 0.58–0.95.
A hazard ratio compares the event rate over time between groups. The estimate and its interval give a more useful account than simply saying that a result passed a check against chance. The group and the events being counted still matter.
The same trial reported more diabetic-retinopathy complications, HR 1.76, 95% CI 1.11–2.78. That pair rules out an uncomplicated success story for me. Cardiovascular benefit and an eye complication signal were observed together in people whose diabetes and existing eye disease affected the clinical picture.
SELECT: established cardiovascular disease without diabetes
SELECT included 17,604 adults with established cardiovascular disease and overweight or obesity, without diabetes. Weekly subcutaneous semaglutide 2.4 mg reduced the combined outcome of cardiovascular death, nonfatal heart attack or nonfatal stroke: HR 0.80, 95% CI 0.72–0.90, P<0.001. That corresponds to the reported 20% relative reduction.
The absence of diabetes matters to the question. The earlier cardiovascular result came from a diabetes population; SELECT tested a different group. Counting serious events gives SELECT its force; the trial directly tests something that a change in body size only invites us to infer.
That judgment has boundaries. The participants already had cardiovascular disease. Generalizing their result to every person interested in weight reduction would move beyond the population studied. The molecule stayed the same, while the experiment changed.
FLOW: kidney events in diabetes
FLOW studied 3,533 people with type 2 diabetes and chronic kidney disease. Weekly subcutaneous semaglutide 1.0 mg reduced the primary kidney-disease composite: HR 0.76, 95% CI 0.66–0.88, a reported 24% lower risk versus placebo. The outcome included kidney failure, at least a 50% decline in eGFR, or death from kidney or cardiovascular causes. eGFR estimates how well the kidneys filter blood.
The components matter to me. A composite called a kidney outcome also included cardiovascular death. Naming its components lets the result remain impressive without making it simpler than the trial actually was.
The study joins the weight and composition findings as another kind of change. Neither the percentage of weight lost nor the proportion of lean tissue can substitute for a measured organ outcome. The converse also holds: a kidney benefit does not answer how strength changes during weight reduction.
Indications and formulations
The existing indication history records first FDA approval for type 2 diabetes in 2017, an oral daily formulation following in 2019–2020, and chronic weight management in 2021. Cardiovascular evidence from SELECT appeared in 2023 and kidney evidence from FLOW in 2024; related indication expansions followed in 2024–2025. A form was approved for MASH in 2025. These uses concern specific approved products and populations.
The named trials here used subcutaneous semaglutide. The oral formulation account explains a different delivery system with low bioavailability. Its existence cannot establish that every outcome is interchangeable across formulations. A compounded semaglutide preparation has no FDA approval.
Future work combining organ outcomes with physical function would bring the bodily and clinical questions together for me. The present evidence already gives substantial reasons to take semaglutide seriously, with adverse effects and tissue changes substantial enough to deserve the same attention.