Retatrutide is an investigational once-weekly "triple agonist" that targets GIP, GLP-1, and glucagon receptors at once. In Phase 2 trials it produced the highest average weight loss ever recorded for a medication. Use our free calculator to explore your projected trajectory based on the published Phase 2 data.
The headline data comes from a Phase 2 randomized controlled trial published in the New England Journal of Medicine in 2023, studying adults with obesity over 48 weeks.
Source: Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. PMID: 37366315
At 24.2%, a 250 lb person would lose about 60 lbs in under a year — exceeding the averages seen with tirzepatide and semaglutide. These are early-phase results in a relatively small trial, so Phase 3 data will be needed to confirm them.
Slows stomach emptying and reduces appetite — the mechanism shared with Ozempic and Wegovy.
Adds appetite and metabolic effects — the second receptor that tirzepatide (Mounjaro/Zepbound) also hits.
Increases energy expenditure (calories burned) and supports fat metabolism — the receptor unique to retatrutide.
No. As of 2026 retatrutide is investigational — it is not FDA-approved and cannot be legally prescribed or sold as a finished medication. It is being studied in the Phase 3 TRIUMPH program. Products marketed online as 'retatrutide' are not FDA-approved and carry significant safety and quality risks. This calculator is for educational interest based on published trial data.
In a Phase 2 trial published in the New England Journal of Medicine, adults on retatrutide 12 mg weekly lost an average of 24.2% of their body weight over 48 weeks — the largest average weight loss reported for a pharmaceutical agent at that point. Lower doses produced proportionally less, and weight had not clearly plateaued by week 48.
Retatrutide is a 'triple agonist' — it activates three receptors: GLP-1, GIP, and glucagon. Semaglutide (Ozempic/Wegovy) targets GLP-1 only, and tirzepatide (Mounjaro/Zepbound) targets GLP-1 and GIP. The added glucagon activity is thought to increase energy expenditure, which may explain retatrutide's larger weight loss in early trials.
Phase 3 trials (the TRIUMPH program) are underway. If results confirm the Phase 2 data and the safety profile holds, an FDA decision could follow once those trials report. Timelines depend on trial completion and regulatory review, so any specific approval date is speculative.
Our free calculator uses the published Phase 2 data to model a week-by-week trajectory for educational comparison.
Try Our Full GLP-1 Weight Loss CalculatorRetatrutide is an investigational drug that is not approved by the FDA and is not available by prescription. This page presents published Phase 2 clinical trial data for educational purposes only and is not medical advice, an endorsement, or a recommendation to obtain retatrutide from any source. Unapproved products sold as "retatrutide" are not quality-controlled and may be dangerous. Always consult a qualified healthcare provider about approved treatment options.