Two compounds, searched together

Retatrutide now has published phase 3 obesity results, but setting them beside tirzepatide’s results is not a head-to-head comparison. The studies enrolled different people, followed them for different periods and used their own analysis methods. Tirzepatide has approved prescription products; retatrutide remains investigational. The direct-comparison TRIUMPH-5 registry had no posted results when checked October 13, 2026.

Semaglutide and tirzepatide are the one pair on this site that has genuinely been randomized against each other. SURMOUNT-5 put 751 adults with obesity and without diabetes on the maximum tolerated dose of one drug or the other for 72 weeks, and tirzepatide came out ahead: a 20.2% average weight reduction against 13.7%. A second trial, SURPASS-2, compared them in type 2 diabetes and also favored tirzepatide, on blood sugar. That is the whole of the direct evidence, and it is narrower than the conclusion usually drawn from it — both trials were open-label, and both capped semaglutide below the highest dose its label now describes. Every other figure on this page is not a head-to-head result at all: it comes from a separate trial with its own placebo arm, its own population and its own duration. Here is what each trial actually reported.

Both stimulate the growth hormone pathway, but their evidence applies to different preparations and populations. Tesamorelin has an approved product for excess abdominal fat in adults with HIV-associated lipodystrophy. Sermorelin has historical diagnostic and pediatric research, with additional adult research involving related GHRH analogs. Geref is no longer marketed; FDA found its withdrawal was not for safety or effectiveness reasons. This is not a head-to-head comparison, and these records do not establish a winner for general wellness.