Eli Lilly has announced promising results from clinical trials of retatrutide, an experimental injectable drug for obesity and type 2 diabetes, demonstrating significantly greater weight loss than the widely used Ozempic.
In a head-to-head trial, patients taking the highest dose of retatrutide (12 mg) lost an average of 47 pounds over 18 months, compared to 21 pounds for those on the highest dose of Ozempic (2 mg). The drug also led to steeper reductions in A1C levels, a key marker of blood sugar control (2.2% vs. 1.8%). Eli Lilly has described retatrutide as a potential “King Kong” of weight-loss drugs due to its mechanism of mimicking three hormones—GLP-1, GIP, and glucagon—compared to Ozempic’s single-hormone approach and Mounjaro’s dual-hormone model.
Retatrutide’s Impact on Sleep Apnea
Separate clinical trials published in The New England Journal of Medicine found that retatrutide also significantly improved symptoms of obstructive sleep apnea (OSA) in overweight and obese adults. In two phase 3 trials involving 691 participants, those receiving retatrutide experienced:
- 12% to 20% body weight loss
- Up to 75% reduction in hypoxic burden (severity and duration of oxygen deprivation during sleep)
- 68% of participants saw over 50% improvement in OSA symptoms, regardless of diabetes status
The trials followed participants for 80 weeks, with doses ranging from 4 mg to 12 mg. The FDA has not yet approved retatrutide, though Eli Lilly plans to submit it for approval in early 2027.
How Retatrutide Works
Retatrutide is classified as a triple agonist, targeting GLP-1, GIP, and glucagon receptors. This mechanism is designed to:
- Reduce appetite by acting on GLP-1 and GIP pathways
- Enhance fat metabolism via glucagon, which helps break down stored fat into energy
- Improve blood sugar control through combined hormonal effects
Eli Lilly has suggested that retatrutide could rival bariatric surgery in clinical weight-loss outcomes, though long-term safety and efficacy data are still pending.
Safety and Side Effects
In the trials, side effects were generally comparable between retatrutide and Ozempic, with gastrointestinal issues (nausea, vomiting, diarrhea) being the most commonly reported. The FDA has warned against illegal online sales of unauthorized retatrutide formulations.
Potential Approval Timeline
If approved, retatrutide could be available for treating obesity, type 2 diabetes, sleep apnea, and knee osteoarthritis. Eli Lilly’s Kenneth Custer, president of Lilly Cardiometabolic, stated in a release: “We believe retatrutide, if approved, could shift the treatment paradigm for people living with type 2 diabetes, obesity and related cardiometabolic conditions."
While retatrutide is not yet FDA-approved, its early results have generated significant interest in the medical and pharmaceutical communities as a potential next-generation obesity treatment.