People treated with injections of retatrutide—an agonist of glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and glucagon receptors—lost substantially more weight than those who received a placebo, according to results from a phase 2 trial involving 338 adults with obesity or who were overweight with at least 1 weight-related condition.

By 24 weeks, participants who had received the highest dose, 12 mg, experienced about an 18% decrease from their original body weight compared with a 1.6% decrease in participants who received a placebo. At 48 weeks, the average percentage weight loss was about 24% in the 12-mg dose retatrutide group.

SAN DIEGO — An experimental drug from Eli Lilly has the potential to provide greater weight loss benefits than any drug currently on the market.

The experimental drug, retatrutide, helped people lose, on average, about 24% of their body weight, the equivalent of about 58 pounds, in a mid-stage clinical trial, the company said Monday from the American Diabetes Association's annual meeting in San Diego. The findings were simultaneously published in The New England Journal of Medicine.

If the results are confirmed in a larger, phase 3 clinical trial — which is expected to run until late 2025 — retatrutide could leapfrog another Lilly weight loss drug, tirzepatide, which experts estimated earlier this year could become the best-selling drug of all time. Tirzepatide is currently approved for Type 2 diabetes under the name Mounjaro; FDA approval of the drug for weight loss is expected this year or early next year.

The new findings, according to Dr. Shauna Levy, a specialist in obesity medicine and the medical director of the Tulane Bariatric Center in New Orleans, are “mind-blowing.”