Eli Lilly's next-generation weight loss drug posted record results in a obesity trial

Snitzer who started his clinical trial of the new GLP1 drug said he expected within 50 days to fit his entire body inside of a standard US Post Office mail shot.

Eli Lilly's next-generation weight loss drug posted record results in a obesity trial

The triple-hormone injection outpaced existing weight loss drugs and approached bariatric surgery outcomes in an 80-week study

By Cris Tolomia, Quartz Media

May 22, 2026

Eli Lilly said Thursday that patients taking the maximum dose of its new drug retatrutide shed an average of 70.3 pounds over 80 weeks, representing a 28.3% reduction in body weight. Close to half of those patients reached the 30% weight loss mark, the pharma giant said.

The TRIUMPH-1 trial enrolled 2,339 adults with obesity or overweight and tested three doses of retatrutide against placebo. By the 80-week mark, roughly 65.3% of those on the 12 mg dose had crossed below a BMI of 30, the cutoff used to define obesity, Lilly said. In a study extension running to 104 weeks, a subset of patients whose BMI was at least 35 — a level associated with elevated cardiovascular and metabolic risk — dropped an average of 85 pounds, equal to 30.3% of their starting weight.

Lilly also tested a lower 4 mg dose not previously used in other trials. Over the same 80-week period, people assigned to that dose dropped an average of 47.2 pounds, a reduction of 19% from their baseline weight. Lilly noted that discontinuations driven by adverse events were actually lower among 4 mg participants — at roughly 4% — than among those receiving placebo, where the figure was close to 5%.

Lilly's chief scientific and product officer Dan Skovronsky described the 30% figure as extraordinary, saying such outcomes had until now been the exclusive territory of bariatric surgery. "We haven't seen that level of weight loss before with these kinds of medicines," Dan Skovronsky told CNBC.

Side effects were consistent with other incretin-based therapies. Among those on the 12 mg dose, nausea was reported by 42.4% of patients, while diarrhea and constipation affected 32% and 26.1%, respectively, according to Lilly. Dysesthesia — a distressing sensory condition involving abnormal skin or nerve feelings — turned up in over 12% of patients assigned to the highest dose, a finding consistent with earlier retatrutide studies. The discontinuation rate due to adverse events at the 12 mg dose was 11.3%.

Unlike existing injectable obesity treatments, retatrutide engages three distinct hormonal pathways simultaneously — GLP-1, GIP, and glucagon. Zepbound, Lilly's current market leader, covers only the first two, and Novo Nordisk's Wegovy is limited to GLP-1 alone. In prior Quartz coverage, Lilly reported Phase 3 results showing retatrutide helped patients with Type 2 diabetes lose up to 16.8% of their body weight over 40 weeks, outpacing existing diabetes drugs.

A regulatory submission to the FDA has not yet been made, though Lilly has indicated that an application could come before the end of the year, NBC News reported. More detailed results from TRIUMPH-1 will be presented at the American Diabetes Association Scientific Sessions, Lilly said. Additional Phase 3 trial results, including data from studies in patients with type 2 diabetes and cardiovascular disease, are expected later this year.