A Next-Generation Drug Triggers Significant Weight Loss, Eli Lilly Reports

(SeaPRwire) –   Eli Lilly has announced promising findings for the first weight-loss drug that targets three relevant hormones, unlike existing GLP-1 medications which only act on one or two. In an official press release, the firm stated that its investigational injectable treatment retatrutide enabled overweight or obese individuals to shed as much as 28% of their body weight across an 18-month period, when compared to participants given a placebo.

This level of weight loss is comparable to the results typically seen with bariatric surgery, according to Kenneth Custer, Lilly’s executive vice president and president of the company’s cardiometabolic health division.

These latest findings build on earlier data for retatrutide from trials involving people living with both obesity and diabetes, which demonstrated the medication helped participants lose 16.8% of their body weight relative to the placebo group, alongside reducing their blood glucose levels. The recently concluded trial excluded participants with diabetes, in order to specifically measure the drug’s efficacy for treating obesity on its own.

The new trial evaluated three different doses of the once-weekly injectable drug. Participants randomly allocated to the lowest 4 mg dose lost roughly 19% of their body weight over the study timeline when compared to the placebo cohort. That weight loss level is comparable to what people achieve after roughly one year on the highest available dose of Zepbound (tirzepatide), another weight loss drug from Lilly. Zepbound acts on two weight-regulating hormones, GLP-1 and GIP, while retatrutide targets both of those plus an additional hormone, glucagon.

The data surrounding retatrutide, which has not yet received approval from the U.S. Food and Drug Administration (FDA), prompts questions about what role each of the expanding number of medications in this class will play in obesity care, and if some may eventually become obsolete. These treatments are available both as injectables (including Wegovy and Zepbound) and oral formulations (such as the oral Wegovy pill and Foundayo). Side effects are a key consideration for people selecting a weight loss medication, and while all drugs in this class carry gastrointestinal side effects including nausea, vomiting and diarrhea, some users experience more intense symptoms on specific treatments than others. In the recent trial, roughly 11% of participants on the highest retatrutide dose discontinued use due to side effects, a rate nearly identical to the dropout rate seen in Lilly’s prior tirzepatide trials. Real-world research indicates the actual discontinuation rate may be marginally higher, at around 15%.

Another critical consideration is the extra health advantages patients may get from these medications. For instance, Novo Nordisk’s Wegovy is approved not only for weight management, but also to reduce risk of cardiovascular events and liver disease, while Zepbound has approval for lowering sleep apnea risk. Both pharmaceutical firms are continuing to investigate their products for other possible health benefits, including for kidney health, arthritis, and substance use disorders. Custer noted that Lilly is carrying out additional trials on retatrutide to gain a clearer picture of whether this triple-action drug offers other health benefits as well.

He added that Lilly is also running a head-to-head comparison of tirzepatide and retatrutide, with results expected in late 2026 or early 2027. Those findings will help clinicians and patients determine which treatment option is the best fit for their needs. “At this point, both medications look set to be core treatments for obesity going forward,” he stated. “We have no issue with competing against our own products.”