A new experimental weight loss drug from Eli Lilly could produce greater weight loss results than popular medications that have made headlines in recent years, according to recent clinical trial results.
The drug, retatrutide, is still being tested and has not yet been approved by the Food and Drug Administration (FDA).
However, researchers say it could become one of the most powerful obesity treatments available if ongoing studies continue to show positive results.
A New Generation
The effectiveness of GLP-1 medications have transformed obesity treatment lately—Ozempic and Wegovy, both of which are based on semaglutide, and Lilly’s Zepbound have become some of the most popular drugs in the world.
Retatrutide is part of a new generation of treatments that researchers hope can deliver even greater weight loss while also helping patients manage diabetes and other obesity-related conditions.
Unlike Ozempic and Wegovy, which primarily target the GLP-1 hormone pathway, retatrutide targets three different hormone receptors: GLP-1, GIP and glucagon.
“These hormones help regulate appetite, blood sugar, fat metabolism, and energy expenditure, which may allow retatrutide to produce greater weight loss than GLP-1s,” Kevin Gendreau, an obesity medicine physician at Signature Healthcare in Massachusetts, told Health.
Stock image: A woman uses a measuring tape to measure weight loss.
Big Losses
Results from a Phase III diabetes trial showed that participants lost between 11.5 percent and 15.3 percent of their body weight over 40 weeks while also seeing significant improvements in blood sugar control.
Health reported that separate obesity trials have produced even larger results. Patients receiving the highest dose of retatrutide lost an average of 28 percent of their body weight over 80 weeks, while nearly half lost 30 percent or more.
Extended to 104 weeks, participants on high doses lost an average of 85.0 lbs of body weight.
Researchers are also studying the drug’s potential use in conditions linked to obesity, including sleep apnea, liver disease and osteoarthritis.
A spokesperson for Lilly told Newsweek in an email that retatrutide’s results thus far, “show what may be possible when we treat obesity comprehensively, and what that could mean for people living with obesity and its related complications.”
A separate study published in the International Journal of Obesity examined semaglutide, tirzepatide and retatrutide in a mouse model of genetic obesity.
Researchers found all three drugs produced significant weight loss and improved markers linked to metabolism and liver health.
What’s Next
Retatrutide remains an investigational drug and is not available to patients outside clinical trials—as noted by Drugs.com, any substance purporting to be retatrutide at this stage is illegitimate and could be dangerous.
However, retatrutide is currently in Phase 3 clinical trials, after which Eli Lilly can formally apply for approval with the FDA—a process that can take up to 10-12 months.
The Lilly spokesperson told Newsweek the company plans to submit retatrutide by the end of 2026 based on the trials.
If the trials and approval process are successful, retatrutide could be available by 2027 or 2028.
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