Does semaglutide actually reduce heart attacks, strokes, and cardiovascular death?
Yes, the evidence is strong and consistent. The largest and most definitive study, the SELECT trial, enrolled 17,604 people with overweight or obesity and established cardiovascular disease but no diabetes. Over a mean follow-up of nearly 40 months, those taking once-weekly semaglutide (2.4 mg) had a 20% lower risk of a combined outcome of cardiovascular death, nonfatal heart attack, or nonfatal stroke compared to placebo (6.5% vs. 8.0%) [2]. This benefit was seen across all subgroups, including those with and without heart failure [1].
These findings are reinforced by other major trials. In people with type 2 diabetes, the SOUL trial (9,650 participants) found that oral semaglutide reduced MACE by 14% (12.0% vs. 13.8%) [8]. A large meta-analysis of 50 trials involving nearly 55,000 participants confirmed that semaglutide reduces all-cause mortality by 15% and the risk of heart attack by 23% [5]. Another meta-analysis of four RCTs (27,617 participants) showed an 19% reduction in MACE [4]. The evidence is not limited to one study or one population; it is replicated across different formulations (injectable and oral) and patient groups (with and without diabetes).
Is the cardiovascular benefit just from weight loss, or does semaglutide do something else?
Weight loss is a major part of the story, but it is not the whole story. In the SELECT trial, participants lost an average of 9.4% of their body weight over two years with semaglutide, compared to 0.9% with placebo [6]. However, a post-hoc analysis of the SUSTAIN-6 trial (which studied semaglutide in type 2 diabetes) found that the degree of weight loss did not predict the reduction in cardiovascular events [3]. This suggests that semaglutide's heart benefits come partly from other mechanisms, such as improving blood pressure, cholesterol, and inflammation [7]. The drug also reduced the development of diabetes and prediabetes by over 70% [7], which itself lowers long-term cardiovascular risk.
In short, while weight loss is a welcome and important effect, semaglutide appears to have direct protective effects on the heart and blood vessels. This is a key point: the drug works even in people who lose only modest amounts of weight.
What are the downsides? Are the benefits worth the side effects?
The main downside is tolerability. In the SELECT trial, 16.6% of people taking semaglutide stopped the drug due to side effects, compared to 8.2% on placebo [2]. The most common side effects are gastrointestinal — nausea, vomiting, and diarrhea — which are usually temporary but can be severe enough to cause discontinuation [5]. A meta-analysis found that semaglutide triples the risk of nausea and quadruples the risk of vomiting [5]. These are non-serious but can be very unpleasant.
However, the trade-off is a clear reduction in serious adverse events overall. The same meta-analysis showed that semaglutide reduced the risk of any serious adverse event by 7% [5]. In the SELECT trial, serious adverse events were less frequent with semaglutide than placebo across all body mass index categories [6]. So, while gastrointestinal side effects are common, the drug reduces the risk of far more serious outcomes like heart attacks and strokes. The decision to use semaglutide should be made with a doctor, weighing the individual's cardiovascular risk against their tolerance for gastrointestinal side effects.
About These Sources
This answer is built on 8 peer-reviewed studies — published from 2023 to 2026, 7 from 2024 or later, 3 in Q1 journals, collectively cited 2,745 times — selected as the most relevant from 15 studies that passed quality screening, drawn from 56 papers retrieved from a database of over 500 million.
Sources used in this answer
Semaglutide and cardiovascular outcomes in patients with obesity and prevalent heart failure: a prespecified analysis of the SELECT trial
In a prespecified analysis of the SELECT trial (17,604 participants), semaglutide reduced MACE by 28% and the composite heart failure endpoint by 21% in patients with heart failure, regardless of ejection fraction subtype.
Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes
The landmark SELECT trial (17,604 participants) showed that semaglutide reduced MACE (cardiovascular death, nonfatal heart attack, or nonfatal stroke) by 20% compared to placebo in people with overweight/obesity and preexisting cardiovascular disease without diabetes.
Semaglutide and Cardiovascular Outcomes in People with Type 2 Diabetes: A SUSTAIN-6 Post Hoc Analysis by Weight Loss Category.
A post-hoc analysis of the SUSTAIN-6 trial found no association between the magnitude of weight loss with semaglutide and subsequent MACE risk, suggesting weight-independent cardioprotective mechanisms.
Cardiovascular benefits of semaglutide: a systematic review and meta-analysis of randomized controlled trials
A meta-analysis of 4 RCTs (27,617 participants) found that semaglutide reduced MACE risk by 19%, with significant reductions in cardiovascular death and nonfatal heart attack, but no significant effect on nonfatal stroke or heart failure hospitalizations.
The adverse effects associated with semaglutide use in patients at increased risk of cardiovascular events: a systematic review with meta-analysis and Trial Sequential Analysis
A systematic review of 50 trials (54,972 participants) found high-certainty evidence that semaglutide reduces all-cause mortality by 15% and myocardial infarction by 23%, but increases the risk of nausea, vomiting, and diarrhea.
Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial
A prespecified analysis of SELECT showed that semaglutide produced sustained weight loss (mean -10.2% at 208 weeks) and improvements in waist circumference, with fewer serious adverse events across all BMI categories.
Semaglutide: The First Anti-Obesity Agent Shown to Decrease Cardiovascular Events
A review of the SELECT trial highlights that semaglutide is the first anti-obesity agent shown to decrease cardiovascular events, with a 20% reduction in MACE and significant improvements in blood pressure, lipids, and inflammation.
Oral Semaglutide and Cardiovascular Outcomes in High-Risk Type 2 Diabetes.
The SOUL trial (9,650 participants) found that oral semaglutide reduced MACE by 14% (12.0% vs. 13.8%) in people with type 2 diabetes and high cardiovascular risk, without increasing serious adverse events.