STEP 1 found Semaglutide users lost 14.9% of starting weight in 68 weeks.
The help was real. So were stomach trouble and weight regain.
The main weight study found a large loss
Over about 16 months, the largest weight study found close to 15% average loss [1]. Your own loss won’t always match that average.
A heart study found fewer strokes and heart attacks [3]. Everyone in that study already had heart disease.
The choices are one weekly shot and one daily pill. It’s FDA-approved for type 2 diabetes and long-term weight care.
When you eat, your gut puts out a hormone called GLP-1. Semaglutide copies that hormone, helping insulin work and easing hunger.
Here’s the main catch: nausea. It often starts as the amount goes up.
On Semaglutide effects, you’ll also see what patients themselves say. Their stories aren’t the same as a study made to compare groups.
We read the published work, but we don’t run a clinic. We can’t choose your treatment or dose.
Study averages won’t say what happens to you. Your doctor can weigh time, cost, other medicines, and your health.
People kept the weight off only by staying on treatment
In STEP 1, 1,961 adults received a weekly shot. They had obesity or extra weight and didn’t have diabetes.
At 68 weeks, the 2.4 mg Semaglutide group had lost 14.9% of starting weight. The placebo group, given a shot without Semaglutide, lost 2.4% [1].
People on Semaglutide lost an added 12.4 percent of their starting weight compared with the placebo group. STEP 5 found the 2.4 mg weekly shot kept weight down for two years [8].
STEP 4 switched treatment after a 20-week start. People who stayed with Semaglutide kept losing weight.
Those people lost another 7.9%. People moved to placebo gained 6.9% [9].
The semaglutide weight loss page gives the full results. Your result won’t match either group’s average exactly.
In mice, the drug cut eating without changing how much energy their bodies burned [4]. A mouse study can’t forecast your result.
These figures can’t tell whether years of treatment, changing amounts, stomach trouble, food costs, doctor visits, and your other medicines fit your health and budget at home over time. Your doctor can help you weigh that long-term load.
Large studies found less heart, kidney, and liver harm
The first heart study followed 17,604 adults who had heart disease plus extra weight. They didn’t have diabetes.
The 2.4 mg shot cut heart attacks, strokes, or heart deaths by 20% [3]. A 95% check asks whether luck could explain a result.
Even after that check, the lower number of heart problems held. An older study called SUSTAIN-6 tested people with type 2 diabetes.
Fewer Semaglutide users had a heart attack, stroke, or heart death [2]. That finding also passed the study’s 95% check against luck.
Next, 3,533 people with type 2 diabetes and kidney disease joined a kidney study. The 1.0 mg shot cut major kidney trouble by 24% [6].
Here’s what major trouble meant: kidney failure, far worse kidney work, or death. The 95% check still favored Semaglutide.
In 2025, a phase 3 study was a large late test in people with fatty, swollen livers. Swelling cleared in 62.9% on Semaglutide and 34.3% on placebo [12].
Full results appear on Semaglutide research. A study result still can’t promise what happens to you.
These gains don’t erase the risks. Your doctor can weigh your health, other pills, cost, and long-term effort.
The main catches were nausea, gallstones, lost muscle, and regain
The safety review wasn’t all good. Nausea affected roughly one-third of patients, though it often passed soon [5].
Gallstones also happened more often. The review couldn’t settle the risk of pancreas or thyroid cancer.
The FDA’s strongest thyroid warning came from tests in mice and rats. In 2024, a review couldn’t find a rise in thyroid cancer among people [15].
The weight didn’t all stay off when treatment ended. In STEP 1, people regained weight equal to 11.6 percent of their starting weight within a year [17].
The lost pounds included both muscle and fat. People didn’t all lose the same amount [16].
The Semaglutide effects page weighs the help against the harm. Those facts can guide your next talk with a doctor.
Reviews can’t rule out every rare harm. Before deciding, ask about warning signs and any thyroid cancer in your family.