GLP-1 receptor agonistsGLP-1 agonists · Incretin medicines

GLP-1 receptor agonists are prescription-only medicines that activate the GLP-1 receptor, mimicking the natural gut hormone but lasting long enough to act over days. Some newer agents are dual agonists, also acting at the GIP receptor.

They matter because the trial results are large by the standards of weight-management research: in a 68-week randomised trial of once-weekly semaglutide, mean body weight fell by about 14.9% versus 2.4% on placebo, and in a 72-week trial of tirzepatide the highest-dose group lost about 20.9% versus 3.1%. Both were run alongside lifestyle support, and both report gastrointestinal side effects as the most common problem.

In practice, these are medicines prescribed and monitored by a clinician for specific clinical criteria — not supplements, and nothing to source privately. This page is background information, not medical advice or a recommendation to take them; dosing and suitability are decisions for the prescriber.

Sources

• Efficacy and Safety of Once-Weekly Subcutaneous Semaglutide 2.4 mg in Adults With Overweight or Obesity (STEP 1, 68 weeks; ~14.9% vs 2.4% mean weight change); PMC8089593
• Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1, 72 weeks; ~20.9% at the highest dose vs 3.1% placebo). N Engl J Med 2022;387:205-216