For years, GLP-1 medications were thought of as weight-loss drugs—effective, yes, but narrowly focused on the number on the scale. The SELECT trial shattered that perception. Published in the New England Journal of Medicine in December 2023, SELECT proved that semaglutide 2.4mg reduced major cardiovascular events by 20% in patients who had never been diagnosed with diabetes.
That finding changed the entire conversation. GLP-1 medications are no longer “just” weight-loss drugs. They are cardiovascular protection tools—and the data behind that claim is among the strongest in modern medicine.
What Was the SELECT Trial?
SELECT (Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity) was a massive, multinational, randomized controlled trial led by Dr. A. Michael Lincoff at the Cleveland Clinic. It enrolled 17,604 patients across 41 countries and followed them for an average of 40 months.
The patients were 45 years or older, had a BMI of 27 or higher, and had established cardiovascular disease (a prior heart attack, stroke, or peripheral artery disease). Critically, none of them had diabetes—this was specifically designed to test whether semaglutide’s heart benefits extended beyond its glucose-lowering effects.
Half received weekly subcutaneous semaglutide at 2.4mg. Half received a placebo. Both groups continued their standard cardiovascular medications.
The Results: 20% Reduction in MACE
The primary endpoint was MACE—major adverse cardiovascular events, defined as a composite of cardiovascular death, nonfatal heart attack, or nonfatal stroke. The results were unambiguous:
| Outcome | Semaglutide | Placebo | Risk Reduction |
|---|---|---|---|
| MACE (primary endpoint) | 6.5% | 8.0% | 20% |
| All-cause death | 4.3% | 5.2% | 19% |
| Heart failure events | — | — | 18% |
| Cardiovascular death | 2.5% | 3.0% | 15% |
All three components of MACE contributed to the overall reduction. This wasn’t driven by one outlier endpoint—it was consistent protection across heart attacks, strokes, and cardiovascular death.
Why This Matters: It’s Not Just About Weight Loss
The most remarkable finding from SELECT wasn’t the 20% MACE reduction itself—it was when that protection appeared. Cardiovascular benefits emerged before patients lost substantial weight. A subsequent analysis published in The Lancet in October 2025 confirmed that only about one-third of the cardiovascular benefit was attributable to weight loss.
This means semaglutide is protecting the heart through mechanisms that go beyond shrinking waistlines. Researchers believe these include:
- Anti-inflammatory effects: GLP-1 receptors exist on immune cells and blood vessels. Semaglutide reduced C-reactive protein (CRP), a key marker of cardiovascular inflammation, significantly more than placebo.
- Improved endothelial function: The lining of blood vessels appears to function better on GLP-1 therapy, reducing plaque instability.
- Blood pressure reduction: Patients on semaglutide experienced meaningful decreases in systolic blood pressure.
- Lipid improvements: Triglycerides dropped, and inflammatory markers improved across the board.
Key Takeaway
The SELECT trial established that semaglutide is a cardiovascular drug that also causes weight loss—not the other way around. This distinction has major implications for insurance coverage and how physicians prescribe these medications.
Who Was Studied—and Who Benefits
SELECT enrolled patients with established cardiovascular disease and overweight or obesity (BMI ≥27), but without diabetes. The average age was about 62 years, and approximately 72% of participants were male.
Benefits were consistent across subgroups including men and women, different ethnicities, various baseline BMI levels, and patients with or without heart failure. A prespecified subanalysis published in The Lancet in August 2024 found that patients with heart failure (both preserved and reduced ejection fraction) benefited equally—with MACE reductions of approximately 28-35% in heart failure subgroups.
Importantly, results published in Diabetes Care in July 2024 showed that cardiovascular protection was consistent whether patients had normal blood sugar, prediabetes in the lower range, or prediabetes in the higher range. Even patients whose blood sugar did not improve on semaglutide still had cardiovascular protection. This confirms the benefits are independent of glucose changes.
Additional SELECT Benefits: Beyond the Heart
The SELECT dataset continues to yield important findings as researchers dig deeper:
- Kidney protection: A 22% reduction in a composite kidney endpoint was observed, laying groundwork for the dedicated FLOW kidney trial.
- Sustained weight loss: Patients maintained an average of 10.2% weight loss at 208 weeks (4 years)—one of the longest weight-loss maintenance datasets for any medication.
- Quality of life: Patients reported improved physical functioning and health-related quality of life scores.
Safety: What to Know
Semaglutide was generally well tolerated, though more patients in the semaglutide group discontinued treatment (16.6%) compared to placebo (8.2%). The primary reason was gastrointestinal side effects—nausea and diarrhea—which are common during the dose escalation phase and typically resolve.
There was a slightly higher rate of gallbladder disorders in the semaglutide group (2.8% vs. 2.3%), consistent with other GLP-1 trials. No unexpected safety signals emerged in this large, long-duration study.
What This Means for You
If you have a history of heart disease, stroke, or peripheral artery disease and are overweight or obese, the SELECT trial provides strong evidence that GLP-1 medications may help protect you from future cardiovascular events. This is true whether or not you have diabetes.
The trial also strengthens the case for insurance coverage. With FDA acknowledgment of cardiovascular benefits, more insurers and employers are covering GLP-1 medications for patients with established heart disease—even when the primary diagnosis is obesity rather than diabetes.
If you’re considering a GLP-1 medication and have cardiovascular risk factors, talk to your healthcare provider about whether semaglutide might be appropriate for you.
Sources
- Lincoff AM, et al. “Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes.” N Engl J Med. 2023;389:2221-2232. DOI: 10.1056/NEJMoa2307563
- Deanfield J, et al. “Semaglutide and cardiovascular outcomes in patients with obesity and prevalent heart failure.” The Lancet. 2024;404:773-86.
- Colhoun HM, et al. “Semaglutide and Cardiovascular Outcomes by Baseline HbA1c.” Diabetes Care. 2024;47(8):1360.
- American College of Cardiology. SELECT Trial Summary. acc.org.