It reduces shelf life from 28 days to under 72 hours and increases contamination risk with repeated needle entry
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
Use the reconstitution calculator to find the right amount for your setup Step-by-Step Reconstitution Protocol What You Need Lyophilized peptide vial Bacteriostatic water (30 mL multi-dose vial) 13 mL syringe with needle (1823 gauge works well for drawing BAC water) Alcohol swabs Permanent marker for labeling The Protocol Wash your hands thoroughly before handling any vials or syringes
For doses requiring volumes below 0.1mL (10 units), 0.5mL insulin syringes offer finer measurement precision
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
