Retatrutide delivered 28.7% average weight loss in its first Phase 3 trial, nearly double the 14.9% that semaglutide achieved at the Wegovy dose, but Ozempic is the drug patients can actually get today.
Both are injected once a week. Both cause nausea. Beyond that, they are different molecules from rival companies at very different stages of regulation.
Retatrutide is Eli Lilly’s investigational triple agonist. Ozempic is Novo Nordisk’s semaglutide, on the market since 2017. The gap in the data is real. So is the gap in availability.
Key Facts
- Retatrutide 12 mg produced 28.7% average weight loss at 68 weeks in the Phase 3 TRIUMPH-4 trial, topline results announced in December 2025.
- Semaglutide 2.4 mg, sold as Wegovy, produced 14.9% at 68 weeks in the STEP 1 trial.
- Eli Lilly plans to file retatrutide with the US Food and Drug Administration in the first quarter of 2027, putting approval in late 2027 at the earliest.
- Ozempic has been FDA-approved for type 2 diabetes since December 2017. Wegovy was approved for weight management in 2021.
- Ozempic lists at about $1,028 a month, with NovoCare self-pay pricing of $349 to $499 as of October 2026.
How do retatrutide and Ozempic differ?
Ozempic is semaglutide, a single-target GLP-1 receptor agonist. Retatrutide, coded LY3437943, is a triple agonist that activates GLP-1, GIP and glucagon receptors at the same time.
A GLP-1 receptor agonist is a drug that mimics glucagon-like peptide-1, a gut hormone that suppresses appetite in the brain and slows stomach emptying.
The glucagon arm is what separates retatrutide from everything already approved. According to Middle Way Nutrition’s 2026 comparison, glucagon receptor agonism can raise energy expenditure and influence fat metabolism in the liver, so the drug works on calories burned as well as calories eaten. GIP, the second receptor, is the same pathway used by Eli Lilly’s tirzepatide, sold as Mounjaro and Zepbound.
Dosing follows the same pattern but not the same numbers. Ozempic steps from 0.25 mg to 2 mg weekly. Retatrutide was studied at 1, 4, 8 and 12 mg weekly in trials. One comparison page, from Phoenix Weight Loss, describes retatrutide as a once-daily injection; the trial protocols and other sources describe once-weekly dosing.
Retatrutide vs Ozempic weight loss: what the trials show
Retatrutide has lost more weight than semaglutide in every trial that has reported, but the studies enrolled different patients and were never run head to head at matched doses.
| Measure |
|---|
