An experimental medicine appears to offer greater weight loss benefits than any obesity drugs already on the market, including the blockbusters Ozempic and Wegovy.

The injectable drug, retatrutide, helped people with obesity shed an average of up to 24 percent of their body weight, or almost 60 pounds, after 48 weeks of treatment, according to the results of a mid-stage clinical trial presented at the American Diabetes Association’s annual meeting in San Diego and published in the New England Journal of Medicine (NEJM) on June 26.

“It is striking that on average, participants with obesity taking the highest dose of retatrutide lost nearly a quarter of their body weight,” said the lead study author, Ania Jastreboff, MD, PhD, an associate professor and the director of the center for weight management at Yale School of Medicine in New Haven, Connecticut, in a statement.

Because participants in the mid-stage retatrutide trial had not yet reached a weight plateau by the time the study ended, it’s possible they might ultimately achieve even more dramatic weight loss results with longer treatment, according to a statement from the drug’s developer, Eli Lilly. The company said it will continue to assess retatrutide for obesity in late-stage trials.

Even People With Both Obesity and Type 2 Diabetes Saw Remarkable Weight Loss on Retatrutide

For the mid-stage retatrutide trial published in NEJM, scientists randomly assigned 338 adults with obesity to take a placebo or one of four different doses of retatrutide: 1 milligram (mg), 4 mg, 8 mg, or 12 mg. Every single patient on the highest retatrutide dose lost at least 5 percent of their body weight after 48 weeks of treatment; about 1 in 4 of them lost at least 30 percent of their weight.

In a separate study of 281 adults with type 2 diabetes, people on the highest dose of retatrutide lost roughly 17 percent of their weight after nine months of treatment, according to results published in the Lancet also on June 26. People with obesity often have a harder time losing weight when they also have type 2 diabetes.

Side effects seen with retatrutide included gastrointestinal issues like nausea, diarrhea, and constipation — similar to the side effects of Ozempic and Mounjaro.

Retatrutide Has the Potential to Work Faster and More Effectively Than Its Competitors

Judging by the results of the mid-stage NEJM trial, retatrutide appears to produce faster and more dramatic weight loss results than other obesity medications.

A study published in NEJM in March 2021 found that Wegovy shots helped people with overweight and obesity lose an average of about 15 percent of their weight over 68 weeks. A study published in NEJM in July 2022 found Mounjaro injections helped people with obesity lose an average of about 21 percent of their weight over 72 weeks.

How Does Retatrutide Work?

All these relatively new weight loss medications work by mimicking hormones in the body that regulate hunger and feelings of satiety. Ozempic is designed to act like one of these hormones, known as glucagon-like peptide 1 (GLP-1). Mounjaro acts like both GLP-1 and another hormone called GIP.

Retatrutide works like GLP-1, GIP, and a third hormone known as glucagon that’s also involved in hunger regulation.