To the Editor: Jastreboff et al. (July 21 issue)1 report a placebo-adjusted weight reduction of 11.9 to 17.8 percentage points among patients with obesity who received tirzepatide, as assessed in the SURMOUNT-1 trial. All the patients were also offered lifestyle interventions. After 72 weeks, weight loss in the placebo group amounted to a mere 3.1% of body mass. The findings in the placebo group were similar to those in the STEP 1 trial of once-weekly semaglutide,2 which showed a 2.4% weight reduction at 68 weeks. However, the placebo-group results in these two trials were strikingly lower than those in previously . . .