Semaglutide and Heart Risk: What SELECT Showed
Every weight-loss medication is sold on weight. Only one of them has completed a large trial asking a harder question — whether it prevents heart attacks and strokes in people who do not have diabetes — and the answer was yes.
That trial is SELECT. It is the reason semaglutide has a cardiovascular indication that tirzepatide, for now, does not, and it changes the conversation for a specific kind of patient we see often: the one whose weight is a problem and whose ApoB or Lp(a) result has just told them why it matters.
Who was in the trial
SELECT enrolled 17,604 adults in 41 countries. Everyone was 45 or older, had a BMI of 27 or above, and had established cardiovascular disease — a prior heart attack, a prior stroke, or symptomatic peripheral artery disease. Nobody had diabetes; that was an exclusion, and it is the point. Semaglutide's heart benefit in people with diabetes was already known. SELECT asked whether it held up without diabetes in the picture.
Participants were randomized to weekly semaglutide or placebo on top of their usual cardiovascular care and followed for a mean of just under three and a half years, with follow-up running as long as five.
What it found
The primary endpoint was the composite most cardiology trials use: cardiovascular death, non-fatal heart attack or non-fatal stroke. It occurred in 6.5% of the semaglutide group and 8.0% of the placebo group — a hazard ratio of 0.80, a 20% relative reduction, with confidence intervals that did not approach zero.
Three things about that result are worth more attention than the headline.
It appeared early. The curves separated within the first months, before most participants had lost much weight. Later analyzes — including a prespecified 2025 analysis in The Lancet — found the cardiovascular benefit was largely independent of how much weight anyone lost or where they started. Whatever semaglutide is doing to the heart, it is not only doing it by making people lighter.
Weight loss was modest by STEP standards. Mean loss was around 9% against roughly 1% on placebo — less than in the pure weight-loss trials, because the population was older, sicker and not selected for obesity. The heart benefit did not need the dramatic numbers.
The benefit was broad. It held across age, sex, baseline BMI, and — in a separate analysis — across baseline blood sugar, including people whose HbA1c was entirely normal.
On the strength of SELECT, the FDA in March 2024 added reduction of major adverse cardiovascular events to Wegovy's label for adults with established cardiovascular disease and overweight or obesity.
What it did not show
Precision matters here more than on most pages, because the finding gets stretched.
SELECT was a secondary prevention trial. Everyone in it had already had a cardiovascular event or had diagnosed vascular disease. It does not tell you that semaglutide prevents a first heart attack in someone with high ApoB and no disease — that is a reasonable hypothesis, and it is not what was tested.
It does not tell you that semaglutide replaces a statin, blood-pressure control or anything else. Participants were on those already. Semaglutide was added, not substituted.
And it is a semaglutide result. Tirzepatide's cardiovascular outcomes trial — SURPASS-CVOT, in people with diabetes — reported non-inferiority against an older GLP-1; its dedicated trial in people without diabetes is still running. It would be surprising if tirzepatide turned out not to protect the heart. It would also be a claim without a finished trial behind it, which is not a claim we make.
What this means for the patient in front of us
The person this page is written for looks like this: mid-fifties, weight that has crept up over a decade, and a recent lipid result — often an ApoB or a Lp(a) drawn for the first time — that put a number on a risk they had suspected. Sometimes a stent already in place.
For that person the case for semaglutide is not "you will lose weight." It is that one intervention moves weight, blood pressure, glucose, inflammation and triglycerides at once, and has a completed trial showing fewer cardiac events on top of standard care. That is a different category of evidence from most of what is sold in this space, and it is fair to say so plainly.
It does not change who is a candidate. The exclusions on the main page still apply, and cardiovascular disease is managed by a cardiologist, not by us. What we do is measure — lipids, ApoB, Lp(a), glucose, inflammatory markers, body composition — and prescribe where it fits the picture, with the cardiologist in the loop.
Frequently asked questions
In SELECT, adults with established cardiovascular disease and overweight or obesity, without diabetes, had 20% fewer major cardiac events on semaglutide than on placebo over about three years. That result is now on the Wegovy label.
The trial only tested people who already had it. Benefit in people at risk but without disease is plausible and untested.
Apparently not. The benefit appeared early and was largely independent of the amount of weight lost.
Not yet in people without diabetes. Its trial in that population is ongoing.
No. SELECT participants stayed on their existing cardiac medications. Semaglutide was added to them.
Possibly, on the basis of weight and metabolic risk — not on the basis of SELECT, which did not study that situation. A conversation with a clinician who has your full panel is the next step.
Where this fits in your plan
Get the advanced lipid markers drawn if they have not been — ApoB, and Lp(a) at least once. Then the Semaglutide Injection page for how the medication is used here.
We measure first. Then we act.
References
- Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. NEJM 2023;389:2221–2232.
- Deanfield J et al. Semaglutide and cardiovascular outcomes by baseline and changes in adiposity measurements: a prespecified analysis of the SELECT trial. The Lancet 2025.
- Kosiborod MN et al. Semaglutide and Cardiovascular Outcomes by Baseline HbA1c and Change in HbA1c in People With Overweight or Obesity but Without Diabetes in SELECT. Diabetes Care 2024;47(8):1360–1369.
- FDA. Wegovy label update — reduction in risk of major adverse cardiovascular events, March 2024.
- American College of Cardiology. SELECT: Semaglutide Reduces Risk of MACE in Adults With Overweight or Obesity. August 2023.
- Back toSemaglutide Injection
- Semaglutide after 60The 65+ trial data is now in, and it is good. What it shows, what it leaves out, and why muscle, bone and medication lists change the plan for semaglutide in older adults.Read
- ApoB explainedApoB counts the particles that can lodge in an artery wall, rather than the cholesterol inside them. Why that distinction matters, and when LDL-C misleads.Read
- Lp(a) explainedLipoprotein(a) is largely genetic, barely responds to lifestyle, and is rarely measured — yet it independently raises cardiovascular risk. Why one test is worth doing.Read
How we write and review our content
ACT 2 Health provides clinician-led care. Treatments are available only to eligible patients following clinical evaluation and within applicable regulations. This content is educational and is not medical advice. Individual results vary.
All medical decisions are made solely by licensed healthcare professionals. Medications are prescribed only when medically necessary. GLP-1 medications are not suitable for everyone. Results may vary.
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