Two recent studies published in separate medical journals indicate that an experimental weight-loss medication developed by Eli Lilly, known as retatrutide, produces substantial weight reduction. The findings were presented at the European Association for the Study of Diabetes and published in The Lancet and the New England Journal of Medicine.
In the study appearing in The Lancet, researchers examined retatrutide’s effectiveness in individuals who were overweight or obese and also had Type 2 diabetes—a demographic where weight-loss pharmaceuticals have historically yielded lower results. Over a 1.5-year period, participants receiving the highest dose of the drug lost approximately 18.8% of their initial body weight, whereas those on a placebo lost 5.1%. Notably, roughly one-third of the highest-dose group achieved a weight loss of at least 25%.
“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,” stated Dr. Juan Pablo Frias, medical director at the Los Angeles Institute for Metabolic Research and a co-author of the Lancet paper.
Beyond weight reduction, the study found improvements in diabetes management. Among those taking the highest dose, 63% reduced their A1C levels to below 6.5%, the clinical threshold for diabetes diagnosis, while also shedding at least 10% of their body weight.
A second study, published in the New England Journal of Medicine, focused on overweight or obese individuals without diabetes and reported comparable outcomes. Participants on the highest dose of retatrutide lost about 25% of their starting weight, compared to just 3.9% in the placebo group. Additionally, secondary benefits were observed: patients with knee osteoarthritis reported reduced pain scores, and those with obstructive sleep apnea experienced fewer apnea episodes.
Retatrutide operates by targeting three distinct hormones involved in weight regulation: GLP-1, GIP, and glucagon. While existing approved drugs such as Ozempic and Wegovy (semaglutide) target only GLP-1, and Mounjaro and Zepbound (tirzepatide) target both GLP-1 and GIP, retatrutide’s triple-action approach may account for its enhanced efficacy.
The safety profile of retatrutide mirrors that of other GLP-1-based medications, with common side effects including gastrointestinal issues such as nausea, vomiting, abdominal cramps, and diarrhea.
Eli Lilly has announced plans to submit a regulatory request to the U.S. Food and Drug Administration in early 2027 seeking approval for retatrutide based on these clinical results.
Three hormones instead of one or two finally makes sense. The knee pain improvement for arthritis patients is a huge, unexpected bonus.
Twenty-five percent weight loss is staggering. I wonder how many insurance companies will actually cover this? It feels like a luxury treatment.