Eli Lilly Drug Shows Significant Weight Loss in New Studies
Retatrutide, which targets three weight-related hormones, led to substantial reductions in body weight in individuals with and without Type 2 diabetes.
Two recent studies indicate that Eli Lilly's experimental drug, retatrutide, can achieve significant weight loss in overweight and obese individuals. The findings were published in separate medical journals and presented at the European Association for the Study of Diabetes meeting.
In one study featured in The Lancet, retatrutide was evaluated in individuals with Type 2 diabetes who were overweight or obese. Participants taking the highest dose of the drug lost an average of 18.8% of their starting body weight over 1.5 years. In comparison, those who received a placebo lost 5.1%. Approximately one-third of participants on the highest dose achieved a weight loss of at least 25%, a result seen in only 3% of the placebo group.
This study also demonstrated improvements in diabetes control. Among those receiving the highest retatrutide dose, 63% achieved an A1C level below 6.5%—the threshold for diabetes—while also losing at least 10% of their body weight.
"This is the most potent drug, showing the greatest percent weight loss in people with Type 2 diabetes with a pharmacological agent, shown to date," said Dr. Juan Pablo Frias, medical director at the Los Angeles Institute for Metabolic Research and a co-author of the study.
A second study, published in the New England Journal of Medicine, focused on individuals who were overweight or obese but did not have diabetes. In this group, the highest dose of retatrutide resulted in an average weight loss of about 25%, compared to 3.9% in the placebo group. The study also noted potential benefits for conditions associated with obesity, including reduced knee pain in participants with osteoarthritis and fewer apnea episodes in those with obstructive sleep apnea.
Retatrutide's mechanism involves targeting three hormones linked to weight regulation: GLP-1, GIP, and glucagon. By acting on these three pathways, the drug may offer more potent weight-loss effects than medications targeting fewer hormones, such as semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound).
Reported side effects for retatrutide were consistent with those seen with other GLP-1 based medications, primarily gastrointestinal issues like nausea, vomiting, diarrhea, and abdominal cramps.
Eli Lilly has announced plans to seek U.S. Food and Drug Administration approval for retatrutide in early 2027, based on these promising study outcomes.