Mounjaro, Wegovy and Heart Health: Cardiovascular Benefits vs Risks
You may already be aware but if not, weight-loss medicines have been shown to offer cardiovascular benefits. Losing weight in general can help our cholesterol, blood pressure and general heart health. Growing research suggests GLP-1 medications can also boost these propertires alongside weight loss. How do those benefits compare with treatment risks, and what happens to protection after stopping? The answer depends on the medicine, the person and the outcome being measured.
Wegovy contains semaglutide, a GLP-1 receptor agonist. Mounjaro contains tirzepatide, which acts on both GIP and GLP-1 receptors. They should not be assumed to have identical cardiovascular evidence.
Evidence reviewed: 11 November 2026. Approximate reading time: 5 minutes.
How has the evidence changed?
Earlier studies largely investigated people with type 2 diabetes, many also living with excess weight. In LEADER (2016), liraglutide reduced a combined outcome of cardiovascular death, non-fatal heart attack or non-fatal stroke: 13.0% experienced an event versus 14.9% with placebo over a median 3.8 years. This established benefit for that treatment and population, rather than proving that every weight-loss medicine protects the heart. [1]
SELECT (2023) addressed a different question: could semaglutide help people with overweight or obesity and established cardiovascular disease who did not have diabetes? Newer research has also examined obesity-related heart failure and compared tirzepatide with another medicine already known to offer cardiovascular protection. [2–4]
Wegovy: what did SELECT show?
SELECT enrolled 17,604 adults aged 45 or older, with BMI of at least 27 and existing cardiovascular disease. Weekly semaglutide 2.4 mg reduced the combined risk of cardiovascular death, non-fatal heart attack or non-fatal stroke by 20% relative to placebo, alongside usual care. [2]
The absolute figures matter: events occurred in 6.5% versus 8.0% over approximately 40 months. That is a difference of 1.5 percentage points, or around 15 fewer people having an event per 1,000 treated during follow-up. It does not mean everyone’s personal risk falls by 20 percentage points.
These results underpin the UK cardiovascular indication for Wegovy in adults with established cardiovascular disease and BMI of at least 27. They do not establish the same event reduction in younger, otherwise healthy people taking treatment solely for weight management, or automatically apply to every dose or formulation. [5]
Mounjaro: encouraging results, with different questions
In SURPASS-CVOT, published in 2025, tirzepatide was compared with dulaglutide in people with type 2 diabetes and established atherosclerotic cardiovascular disease. Average BMI was 32.6, although not every participant necessarily had overweight or obesity. [3]
Major cardiovascular events occurred in 12.2% with tirzepatide versus 13.1% with dulaglutide. Tirzepatide met the trial’s criterion for non-inferiority, meaning it was not unacceptably worse than an already protective comparator. It did not demonstrate statistically significant superiority for the primary outcome. These percentages cannot be compared directly with SELECT to decide which medicine is better.
SUMMIT studied 731 people with obesity and heart failure with preserved ejection fraction (HFpEF), where the heart’s pumping percentage can remain normal despite impaired filling. Cardiovascular death or worsening heart failure occurred in 9.9% with tirzepatide versus 15.3% with placebo over a median two years. The benefit was mainly fewer worsening heart failure events; reduced cardiovascular mortality alone was not established. [4]
An October 2026 SURPASS-CVOT analysis also found no clear difference between tirzepatide and dulaglutide in heart failure hospitalisations or urgent visits, whether participants had previous heart failure or not. This subgroup analysis should not override SUMMIT: the populations and comparators differed. [12]
Do men, women and different age groups benefit equally?
In SELECT, the relative cardiovascular effect was consistent between men and women, with no convincing evidence of a treatment difference by sex. Women lost more weight, but this did not translate into clearly greater cardiovascular protection. Only about 28% of participants were women, making their separate estimates less precise. [6]
SELECT’s average age was around 62, and nobody was under 45. Its findings therefore cannot simply be extended to younger adults. Available subgroup findings do not establish a clear age group that uniquely benefits; evidence is less certain for very frail older people. Age, muscle strength, nutrition, kidney function and other medicines still matter when assessing suitability. [2,6,9]
What about diabetes, heart failure and other conditions?
Diabetes is not essential for benefit: SELECT specifically excluded it. However, people with diabetes, previous cardiovascular events or kidney disease can have different baseline risks, so an apparently similar relative effect may produce a different absolute benefit.
For obesity-related HFpEF, the STEP-HFpEF programme found semaglutide improved symptoms, physical limitations and walking performance, including in studies with and without diabetes. These symptom findings complement SUMMIT, but neither programme proves these medicines suit every form or severity of heart failure. Severe or unstable disease needs specialist assessment. [7]
Which risks need monitoring?
Both medicines can increase resting heart rate. Nausea, vomiting or diarrhoea may cause dehydration, kidney problems and dizziness; low blood pressure can also occur. This deserves particular attention if you take blood-pressure tablets or diuretics. Persistent palpitations, fainting or difficulty keeping fluids down require prompt clinical advice. Do not adjust heart medicines yourself. [8,9]
Low blood sugar is more likely when treatment is combined with insulin or sulfonylureas, so prescriptions may need review. Pancreatitis and gallbladder problems are other relevant risks. In SELECT, adverse events led to permanent treatment discontinuation in 16.6% with semaglutide versus 8.2% with placebo, showing that benefit and tolerability must both be considered. [2,8,9]
Call 999 for suspected heart attack or stroke, collapse or severe sudden breathlessness. Do not assume these symptoms are ordinary treatment side effects.
Is the benefit simply down to losing weight?
Weight loss can improve blood pressure, glucose control, mobility and several cardiovascular risk factors. But improving risk factors does not always prove fewer heart attacks: Look AHEAD (2013) improved weight and fitness in adults with overweight or obesity and diabetes without significantly reducing its primary cardiovascular outcome. [10]
A 2025 SELECT analysis found semaglutide’s cardiovascular benefit was not explained simply by the amount of weight lost, suggesting additional mechanisms. This analysis does not prove exactly how protection occurs or mean that weight management is unimportant. [11]
What happens to cardiovascular health after stopping treatment with mounjaro or wegovy?
Recent headlines describe a loss of cardiovascular protection after stopping GLP-1 medicines, sometimes called ‘metabolic whiplash’. Two different findings need separating.
The tirzepatide withdrawal analysis highlighted by the BHF found that weight regain after stopping was associated with reversal of improvements in blood pressure, cholesterol and blood glucose. It did not establish more heart attacks, strokes or deaths. [13,14]
A 2026 observational study of US veterans with type 2 diabetes found that stopping GLP-1 treatment for one or two years was associated with approximately 14% and 22% higher relative risk, respectively, of a combined outcome of heart attack, stroke or death from any cause, compared with continuous treatment. These are not percentage-point increases or separate estimates for each outcome. [15]
Only 0.03% of GLP-1 users received tirzepatide, limiting Mounjaro-specific conclusions. The study cannot prove that stopping caused harm, or that risk exceeded what it would have been without ever starting treatment. Illness and other differences between people stopping and continuing may influence the findings. ‘Metabolic whiplash’ is a descriptive term, not an established withdrawal syndrome. [15]
What does this mean for you?
For people with an appropriate clinical indication, cardiovascular benefits can outweigh treatment risks, particularly when baseline cardiovascular risk is high and treatment is tolerated. Semaglutide has demonstrated fewer major cardiovascular events in the SELECT population; tirzepatide has demonstrated benefit in obesity-related HFpEF and cardiovascular non-inferiority to dulaglutide in high-risk type 2 diabetes. The evidence is specific to the medicine and population studied. [2–4]
Evidence that protection may diminish after stopping strengthens the case for long-term treatment planning, regular review and support if treatment ends. It does not mean everyone must remain on medication indefinitely, or that stopping inevitably causes a heart attack or stroke. Discontinuation findings do not justify continuing despite a serious adverse reaction. If stopping is needed, agree follow-up for weight, blood pressure and, where relevant, glucose and other medicines with your prescriber. [8,9,13–15]
Sustainable weight loss can support heart health, but the best choice depends on your history, medicines and treatment goals. Continue prescribed cardiovascular treatment, balanced nutrition, suitable activity and smoking cessation. A confidential, individual assessment can help explore weight-management options to see if you could benefit.
This article provides general education and does not replace an individual assessment. Images are illustrative and do not depict trial participants.
