Side-by-side compound comparison Receptor targets Tirzepatide GLP-1 + GIP (dual) Semaglutide GLP-1 only Retatrutide GLP-1 + GIP + Glucagon (triple) Half-life Tirzepatide ~5 days Semaglutide ~7 days Retatrutide ~6 days Dosing frequency Tirzepatide Once weekly Semaglutide Once weekly Retatrutide Once weekly Max studied dose Tirzepatide 15 mg / week Semaglutide 2.4 mg / week (Wegovy) Retatrutide 12 mg / week Peak weight loss Tirzepatide 22.5% (SURMOUNT-1, 72 wk) Semaglutide 15.8% (STEP-1, 68 wk) Retatrutide 24.2% (Phase 2, 48 wk) FDA status (June 2026) Tirzepatide Approved (T2D, obesity, OSA) Semaglutide Approved (T2D, obesity, CV risk) Retatrutide Investigational Phase 3 Head-to-head Tirzepatide 20.2% vs semaglutide 13.7% (SURMOUNT-5) Semaglutide Retatrutide Not yet head-to-head vs tirzepatide HFpEF benefit Tirzepatide Yes (SUMMIT, HR 0.62) Semaglutide Yes (STEP-HFpEF) Retatrutide Not yet studied Unique advantage Tirzepatide Best-in-class FDA-approved efficacy
Brand-name tirzepatide (Mounjaro for diabetes, Zepbound for weight management) comes in pre-filled, single-dose injection pens at specific strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg
Several mechanisms have been suggested [5,17,33,34]: (1) reduced intrinsic factor secretion, (2) decreased vitamin B12 release from protein complexes, (3) microbial overgrowth due to slowed intestinal transit, and (4) decreased vitamin B12-intrinsic factor complex receptors
A common pattern is a 50 mg vial reconstituted with 2.0 mL bacteriostatic water, producing 25 mg/mL
In both valleys, the subsurface geology indicates the rivers early history, at times in somewhat surprising fashion
