Drug Steps Up Obesity Reduction

By the Editorial Team · Wednesday, September 30, 2026

Eli Lilly's weight-loss drug retatrutide significantly reduced body weight and improved blood sugar control in a large trial involving adults with Type 2 diabetes, with the highest dose leading to nearly 19% average weight loss over 80 weeks. Its triple hormone receptor targeting may offer advantages over existing treatments, but the drug still requires regulatory approval and further research to confirm long-term benefits.

A new weight-loss drug, retatrutide, has demonstrated significant potential in reducing body weight and improving blood sugar control in people with Type 2 diabetes, according to results from a large clinical trial. The drug, developed by Eli Lilly, mimics three gut hormones—GLP-1, GIP, and glucagon—to regulate appetite, blood sugar levels, and metabolism.

The randomized, double-blind, placebo-controlled trial, known as TRIUMPH-2, included 2,047 adults with a body mass index (BMI) of 27 or higher and Type 2 diabetes. Participants were enrolled across eight countries: Argentina, Australia, Brazil, India, Mexico, Romania, Spain, and the United States. Over the course of 80 weeks, subjects received weekly injections of either placebo or varying doses of retatrutide (4 mg, 9 mg, or 12 mg), in addition to guidance on diet and physical activity.

At the end of the study period, those on retatrutide experienced substantial weight loss compared to the placebo group. Individuals receiving the highest dose, 12 mg, lost an average of 18.8% of their body weight, while those on 4 mg and 9 mg doses lost 11.9% and 16.8%, respectively. In contrast, participants in the placebo group lost an average of 5.1%. Nearly half (47%) of those taking the 12 mg dose shed at least 20% of their initial weight, and 31% lost at least a quarter of their body weight. By comparison, only 6% and 3% of the placebo group achieved similar reductions.

In addition to weight loss, retatrutide was associated with improvements in glycemic control and reductions in cardiometabolic risk factors. About 72% of participants on retatrutide reached a standard blood sugar threshold used for diagnosing Type 2 diabetes remission, compared to 29% in the placebo cohort. The drug also showed reductions in levels of C-reactive protein, an inflammatory marker linked to cardiovascular risk.

The safety profile of retatrutide was generally similar to that of other GLP-1 receptor agonists currently approved for use. The most commonly reported side effects were gastrointestinal in nature, including diarrhea in 27-34% of treated patients, compared with 13% in the placebo group, and nausea affecting 14-28% versus 8%, respectively.

Researchers noted that retatrutide's ability to engage three different hormone receptors, including glucagon receptors that increase energy expenditure, may offer advantages over existing drugs that target only one or two pathways. They emphasized the need for additional studies to assess whether these benefits translate into long-term improvements in obesity-related complications.

The study findings will be presented at the European Association for the Study of Diabetes meeting in Milan and have been published in The Lancet medical journal. Retatrutide has not yet received approval from regulatory agencies.

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