Semaglutide

What it is

GLP-1 is a hormone the gut releases after eating that slows digestion, helps the pancreas release insulin, and signals the brain that the body has had enough food. Semaglutide copies this hormone's structure closely enough to activate the same receptor, but with chemical changes that let it resist the rapid breakdown the natural hormone normally undergoes.

Because of that extended activity, semaglutide can be given as little as once a week by injection, or, in a newer form, as a daily tablet. Researchers describe its effects as working through the gut-hormone system to reduce appetite and slow stomach emptying, rather than through a stimulant-like mechanism.

How it is studied

Semaglutide has been studied in large randomized, placebo-controlled human trials, some following participants for two years or more, covering weight management, type 2 diabetes, and cardiovascular outcomes in people who already have heart disease.

What studies report

• In a 64-week trial of a daily oral tablet, participants lost about 14 percent of their body weight on average compared with about 2.4 percent on placebo, and 76 percent of the treatment group lost at least 5 percent of their body weight compared with 31 percent on placebo. [1]
• In a large cardiovascular outcomes trial in overweight or obese adults who already had heart disease, weekly semaglutide was linked to a 20 percent reduction in major adverse cardiovascular events over about five years. [2]
• In a two-year trial, participants who continued weekly semaglutide maintained an average weight loss of about 15 percent at the 104-week mark, showing the effect held up with continued treatment rather than fading. [3]

What is not known

Most of the long-term outcome data available comes from trials of two years or less, so effects and safety beyond that window are less well established. Because semaglutide requires ongoing treatment to maintain its effect, what happens to weight and metabolic markers many years after stopping, beyond the trial periods studied, is not addressed in the sources reviewed here.

Reported adverse findings

• Trials reported gastrointestinal side effects such as nausea as the most common issue, alongside a rare risk of a thyroid tumor type seen in animal studies, leading to a warning against use in anyone who has had that cancer themselves or has a relative who has, or who carries a related genetic syndrome. [1]

Regulatory status

Semaglutide is FDA-approved under several brand names for different uses: as Ozempic for type 2 diabetes, as Wegovy for chronic weight management, and as Rybelsus, an oral tablet, for type 2 diabetes; an oral form of Wegovy for weight management also gained approval. It is approved only for these specific, labeled uses and is available by prescription; it is not approved as a general-purpose weight-loss product outside these indications.