WHAT THE HEART STUDIES MEASURED
A 17,604-person study linked Semaglutide with 20% fewer serious heart problems.
Heart results come first; then you’ll see weight, side effects, and questions the studies haven’t answered.
The largest study found fewer serious heart problems
A large study followed 17,604 adults; each had heart disease, none had diabetes, and all carried extra weight. Death caused by heart trouble, stroke, or heart attack occurred 20% less often with Semaglutide [3]. Another study found that average weight fell 14.9% over 68 weeks [1].
Doctors use Semaglutide to treat type 2 diabetes and help with weight over time. It also has uses for some heart risks. In 2025, use widened to a serious liver disease caused by fat buildup and scarring. The medicine copies GLP-1, a gut hormone that guides hunger and blood sugar. Because stomach trouble is common, ask your doctor how the risk could affect you.
The heart study gives the clearest result
The largest heart study enrolled 17,604 adults who did not have diabetes; each already had heart disease. Everyone had a body mass index of 27 or more, meaning weight was high for height. Researchers compared a weekly 2.4 mg shot with placebo, a look-alike shot holding no medicine.
Stroke, heart attack, or death caused by heart trouble occurred 20% less often with Semaglutide [3]. The report’s 95% range pointed the same way, while another check made chance a poor fit for the result. A 2024 review found the benefit across many starting weights and blood sugar levels [13].
A smaller heart study called SUSTAIN-6 included 3,297 people with type 2 diabetes and a serious risk of heart trouble. At 0.5 or 1.0 mg, Semaglutide cut the same three problems by 26% [2]. A separate 95% range also favored the medicine. Eye trouble happened more often, and a third 95% range backed that warning [2]. If you have eye disease, tell your doctor before discussing this medicine.
Semaglutide copies a hormone made in your gut
Semaglutide is a 31-amino-acid protein; amino acids are small units used to build proteins. It copies GLP-1, a gut hormone that helps the body handle food [12]. Your own GLP-1 soon fades, but Semaglutide copies GLP-1 and outlasts GLP-1 by far.
One small part, listed as number 8 in the lab, was changed for a practical reason. That part resists DPP-4, a body substance that would otherwise remove the medicine too quickly [12]. A different part gives Semaglutide a 1-week stay in your blood [12].
You can receive a weekly injection beneath the skin or take a tablet each day. The tablet has an added ingredient that helps medicine pass the stomach [12]. The page how does semaglutide work shows how those changes make the long stay possible.
Weight fell with treatment, then some returned
STEP 1 was a weight study of 1,961 adults without diabetes who were followed for 68 weeks. All carried extra weight. Average weight fell 14.9% with Semaglutide 2.4 mg, compared with 2.4% on placebo [1]. The gap was about 12 percentage points, and blood pressure and blood sugar improved too [10].
The change didn’t last on its own. After people stopped Semaglutide in the STEP 1 follow-up, they regained about 11.6 percentage points within a year [19]. For you, the study supports care over time rather than one brief treatment.
Choose the study that matches your question
No page here can examine you, prescribe medicine, or sell it. Notes beside the numbers lead to the study reports. You can open those reports from the references page.
The Semaglutide research page covers the main heart, kidney, and weight findings. The dose page lists amounts used in studies, but it can’t choose one for you. When a study didn’t test a claim, we say that the answer is still unknown.