Retatrutide Research Guide
Everything you need to know about retatrutide: mechanism, dosing schedules, reconstitution math and how it compares with tirzepatide and semaglutide.
What retatrutide is
Retatrutide is an investigational triple agonist targeting GLP-1, GIP and glucagon receptors. The added glucagon activity raises energy expenditure alongside the appetite suppression seen with GLP-1 and dual agonists, which is why Phase 2 weight-loss results exceeded tirzepatide comparators.
Dosing and titration
Trial designs used weekly subcutaneous dosing with slow escalation — commonly 1–2 mg for four weeks, then stepping toward 4, 8 and 12 mg at multi-week intervals. Slower escalation markedly reduces nausea and GI events.
Reconstitution
A 10 mg vial with 1 mL BAC water yields 10 mg/mL, so a 2 mg dose is 20 units on a U-100 syringe. Store reconstituted vials at 2–8 °C and use within about 30 days.
Frequently asked questions
Is retatrutide stronger than tirzepatide?
Phase 2 data showed greater mean weight loss for retatrutide than tirzepatide comparators, attributed to added glucagon-receptor activity, but head-to-head Phase 3 data is still pending.
How often is retatrutide dosed?
Once weekly, subcutaneously, with dose escalation every four weeks in trial protocols.
What are the main side effects?
Dose-dependent nausea, vomiting, diarrhoea and reduced appetite, most common during escalation and usually easing at a stable dose.