Semaglutide

Semaglutide is the active ingredient, not a brand. It is a GLP-1 receptor agonist that mimics a natural gut hormone released after eating, and it is the molecule inside Ozempic, Wegovy and Rybelsus. When people compare “Wegovy versus Ozempic,” they are really comparing two dose ceilings and two labels wrapped around the same compound.

Its defining property is how long it lasts. The labels put semaglutide’s elimination half-life at roughly one week, and state that after a final 2.4 mg injection the drug remains in circulation for about five to seven weeks. That is what makes once-weekly dosing possible, and it is also why stopping is not instant: side effects, appetite suppression and drug interactions all taper over more than a month rather than ending on the last injection day. Our washout calculator works the timing out.

The evidence base is unusually deep for a weight medication. STEP 1 showed 14.9% average weight loss at 68 weeks against 2.4% on placebo. SELECT, with 17,604 participants who had heart disease and excess weight but no diabetes, found a 20% relative reduction in cardiovascular death, heart attack or stroke (hazard ratio 0.80) over a mean 39.8 months. ESSENCE, published in 2025, reported resolution of steatohepatitis without worsening fibrosis in 62.9% of treated patients versus 34.3% on placebo.

A frequent confusion is equating the ingredient with a specific dose. Semaglutide exists at 0.25 mg through 2.4 mg weekly by injection and at several oral strengths, and a prescription for “semaglutide” means nothing without the dose, the route and the product. This matters most with compounded vials, which are dosed in units rather than milligrams.

Ask your clinician which branded or compounded product the prescription points to, what maintenance dose is the target, and — if you are considering stopping — how the multi-week tail affects surgery, pregnancy planning or a switch. The semaglutide drug page and dosage chart have the specifics.