Can Weight-Loss Injections Prevent a Heart Attack or Stroke?

Semaglutide belongs to a class of medications called GLP-1 receptor agonists. Originally developed to manage type 2 diabetes, they help control blood sugar, reduce appetite, and slow stomach emptying, which can lead to significant weight loss. But researchers have found that the cardiovascular benefits appear to go beyond weight loss alone.

Semaglutide is thought to reduce inflammation in blood vessels, lower blood pressure, and improve cholesterol levels. These effects may help stabilise fatty plaques in the arteries, making them less likely to rupture and cause a heart attack or stroke. Importantly, weight loss itself also eases the strain on the heart and improves many risk factors.

The National Institute for Health and Care Excellence (NICE) has recommended semaglutide as an option for people with established cardiovascular disease — such as those who have already had a heart attack, stroke, or peripheral arterial disease — and who have a body mass index (BMI) of 27 kg/m² or higher. Semaglutide is also available through a separate NICE route for weight management, which has its own, different eligibility criteria — the recommendation described here is specifically for reducing cardiovascular risk.

It is not a quick fix. NICE guidance emphasises that semaglutide should be used alongside a reduced-calorie diet and increased physical activity, and it is only one part of a broader cardiovascular risk management plan that includes controlling blood pressure, cholesterol, and blood sugar.

The recommendation follows key clinical trials, including the SELECT trial, which showed that semaglutide reduced the risk of major adverse cardiovascular events — such as heart attack, stroke, or cardiovascular death — by about 20% in people with pre-existing heart disease and excess weight. These findings were significant enough for NICE to approve its use specifically for cardiovascular prevention on the NHS.

While the results are promising, it is important to note that not everyone will respond the same way, and the medication does not eliminate all heart risk. It works best as part of a comprehensive approach to cardiovascular risk, overseen by the clinician who prescribes it.

As with any medication, weight-loss injections can cause side effects. The most common are gastrointestinal, including nausea, vomiting, diarrhoea, and constipation. These often improve over time. Less common but more serious risks can include pancreatitis and gallstones.

You should only start semaglutide under the supervision of the clinician who prescribes it, who can monitor your progress and manage any side effects. The Cardiology Clinic does not prescribe or supervise weight-loss injections — for cardiovascular prevention these are arranged through your GP or an NHS specialist service. What we do is assess your heart and your overall cardiovascular risk, which gives you and your GP a clearer picture when weighing up treatment.

This information draws on guidance from the National Institute for Health and Care Excellence (NICE), the British Heart Foundation and the NHS, together with the published SELECT trial results. For the most up-to-date recommendations and research, you can refer to their websites.