Semaglutide

What the evidence says

Semaglutide is a GLP-1 receptor agonist used as a prescription treatment for chronic weight management in eligible patients. In STEP 1, 1,961 adults with overweight or obesity and without diabetes were randomized to weekly semaglutide 2.4 mg or placebo, both alongside lifestyle intervention, for 68 weeks.^[1]

Participants assigned semaglutide lost substantially more weight and were much more likely to reach thresholds of 5%, 10%, and 15% weight loss. The trial also reported improvements in several cardiometabolic risk factors and participant-reported physical functioning.^[1]

STEP 5 extended the randomized evidence to 104 weeks and found mean weight change of -15.2% with semaglutide versus -2.6% with placebo. A STEP 1 extension also showed that participants regained about two-thirds of their prior loss within a year after treatment stopped, supporting obesity treatment as ongoing care rather than a short course.^[3][4]

SELECT tested a harder clinical outcome in 17,604 adults with established cardiovascular disease and overweight or obesity but no diabetes. Semaglutide reduced the composite of cardiovascular death, nonfatal heart attack, or nonfatal stroke, but this secondary-prevention population should not be generalized to every person seeking weight loss.^[5]

This is strong evidence for obesity treatment, not direct evidence that semaglutide slows biological aging in otherwise healthy people. Benefits depend on appropriate patient selection, dose escalation, long-term planning, and management of adverse effects with a prescriber.^[2]