Fact-check: Stanford Health Care's hour on GLP-1 receptor agonists, the truth behind the trend

What the video covers

Michael Blumen, an ambulatory care clinical pharmacist and diabetes educator at Stanford Health Care, gives a patient webinar in four parts: how glucose and insulin go wrong in type 2 diabetes and what GLP-1 does; each GLP-1 product with its route, frequency and dose steps; the benefits and risks, walking through A1c and weight results trial by trial and then the cardiovascular and kidney outcome trials; and how the drugs fit into diabetes management. Questions follow.

What it gets right

The physiology section is careful and correct, including the glucose-dependence of GLP-1's insulin effect and the separate roles in glucagon suppression, gastric emptying and satiety. The product tour is accurate on dose steps: Mounjaro and Zepbound at 2.5, 5, 7.5, 10, 12.5 and 15 mg; Ozempic at 0.25, 0.5, 1 and 2 mg. The trial results are in the right direction and mostly the right size. SUSTAIN 1's A1c reduction of about 1.5 points on 1 mg against near zero on placebo over 30 weeks; SUSTAIN FORTE's 2.2-point fall on 2 mg over 40 weeks in 961 patients (PubMed 34293304); SURPASS-2's 2.3-point fall on tirzepatide 15 mg against semaglutide 1 mg over 40 weeks in about 1,880 patients (PubMed 34170647); SUSTAIN-6's 26 percent relative reduction in major cardiovascular events (PubMed 27633186); FLOW's 24 percent reduction in the kidney composite (PubMed 38785209). His aspirin comparison, that primary-prevention aspirin gives about an 11 percent relative reduction for a similar composite, is a fair benchmark. The retinopathy caution, that rapid glucose lowering can worsen existing diabetic retinopathy, is in the Ozempic label.

What it leaves out or overstates

Several figures are quoted from memory and drift. The tirzepatide-versus-semaglutide obesity trial (SURMOUNT-5) is described as lasting 12 months with "almost 18,000 patients"; it ran 72 weeks and randomised 751 people, with mean losses of 20.2 percent on tirzepatide and 13.7 percent on semaglutide 2.4 mg. The talk's rounding of SURPASS-2 to "about 20 percent of body weight" for tirzepatide is also high; SURPASS-2 was a diabetes trial and the 15 mg arm lost 11.2 kg, about 12 percent. The bigger obesity numbers belong to SURMOUNT-1.

Because the audience is a diabetes program, the obesity indications get less time than the glycaemic ones, and the SELECT trial in people without diabetes is not covered. Adverse events are described qualitatively; the label tables give the rates.

Where to go next

The UCSF grand rounds next in this playlist is the obesity-side counterpart, with one-year and two-year figures for every approved agent. The trial explorer on FormBlends Research charts every arm with its PubMed id. For every agent's label doses in one table, see GLP-1s Explained. FormBlends' compounded semaglutide and tirzepatide (formblends.com) are not FDA approved and were not the products in any trial named here.