# Semaglutide: The Cardiovascular-Outcomes Record, Read Straight > Semaglutide cut major adverse cardiovascular events by 20% in 17,604 adults with heart disease and obesity (SELECT). A plain-spoken digest of the trials, cited line by line. Most of what is online about semaglutide is weight-loss noise. This is the heart-and-vessel evidence first, the side effects in full, and every number tied to the study that measured it. ## The short version Here is the honest one-paragraph take. Semaglutide is a GLP-1 receptor agonist (a lab-made copy of a gut hormone your body releases after you eat) that is an FDA-approved prescription medicine for type 2 diabetes, long-term weight management, lowering the risk of heart attack and stroke in people with heart disease and excess weight, and, since 2025, a serious form of fatty liver disease. The headline most people miss: in a trial of 17,604 adults with established heart disease and obesity but no diabetes, it cut major cardiovascular events by 20% [3]. It also drove a mean 14.9% body-weight drop over 68 weeks in a separate weight study [1]. The catch is the stomach: nausea, burping, and changed bowel habits are common, especially early. What people report — including the unglamorous downsides — is collected on [the effects page](/effects). The trials, the mechanism, and the numbers are below. ## Lead with the heart, not the scale The cardiovascular result is the one that should run first, because it is the hardest endpoint and the largest trial. In SELECT, 17,604 adults with prior heart disease and a body-mass index of 27 or higher — and no diabetes — were randomized to once-weekly semaglutide 2.4 mg or placebo. The composite of cardiovascular death, nonfatal heart attack, and nonfatal stroke fell by 20% (hazard ratio 0.80; 95% CI 0.72-0.90; P<0.001) [3]. A 2024 follow-up analysis confirmed the benefit held across baseline weight and blood-sugar categories [13]. That is a cardiovascular drug that also happens to lower weight, not the other way around — and it is the reason the [semaglutide heart failure](/heart-failure) and broader CV story carries this site. The diabetes cardiovascular signal came years earlier. In SUSTAIN-6, once-weekly semaglutide (0.5 or 1.0 mg) cut the same three-part endpoint by 26% in 3,297 people with type 2 diabetes at high cardiovascular risk (HR 0.74; 95% CI 0.58-0.95) [2]. One caveat lands honestly here: diabetic-retinopathy complications were more frequent in that trial (HR 1.76; 95% CI 1.11-2.78) [2], a point covered plainly on [the effects page](/effects). ## What semaglutide is, in plain terms Semaglutide is a 31-amino-acid peptide — a short protein — engineered as a long-acting analogue of human GLP-1 (glucagon-like peptide-1, the gut hormone that tells your pancreas to release insulin and tells your brain you are full) [12]. Native GLP-1 lasts about two minutes in the blood. Two chemistry tricks stretch semaglutide to roughly a week: a swapped amino acid at position 8 blocks the enzyme DPP-4 (the protease that normally chews up GLP-1), and a fatty-acid chain lets it grip onto albumin (the most abundant protein in blood) so the kidneys clear it slowly [12]. That ~1-week half-life is why the injection is once weekly [12]. It comes two ways: a once-weekly shot under the skin, and a once-daily tablet co-formulated with an absorption helper called SNAC [12]. The deeper mechanism — how it reaches the brain's appetite circuits — gets its own page: [how does semaglutide work](/how-it-works). ## The weight-loss number everyone quotes In STEP 1, once-weekly semaglutide 2.4 mg produced a mean body-weight change of -14.9% from baseline to week 68, versus -2.4% with placebo, in 1,961 adults with overweight or obesity and no diabetes [1] — a gap of about 12 percentage points. Body-composition and risk-factor analyses from the STEP program showed improvements in waist circumference, blood pressure, lipids, blood sugar, and inflammatory markers alongside the weight loss [10]. It is real, it is large, and it is not permanent on its own. After people stopped semaglutide in the STEP 1 extension, they regained a mean of roughly 11.6 percentage points of body weight within a year, and the metabolic gains drifted back toward baseline [19]. Translation: this behaves like a chronic medication for a chronic condition, not a one-time fix. The full safety picture lives on [the effects page](/effects). ## How to read this site This is an editorial digest, not a clinic and not a store. Every quantitative claim here points to a numbered citation, and the [references](/references) page lists each one with its DOI and PubMed link. The [Semaglutide research](/research) page walks the mechanism and the major trials in depth. The dosing page describes what was given to whom in the trials and on the label — third person, never as advice. And because the internet's worst semaglutide content is the unsourced kind, the rule here is simple: if a study did not measure it, this site does not claim it. --- A plain-spoken audit of the semaglutide trial record with the cardiovascular outcomes read first and the hype read last — an editorial digest, not a clinic, a prescriber, or a vendor.