retatrutide clears – Eli Lilly says its next-generation weekly obesity injection retatrutide cleared a crucial late-stage trial, with the highest dose producing average 28.3% weight loss over 80 weeks and about 45% of patients reaching at least 30% loss. The company also tested a
On a Thursday that sounded routine in the pharmaceutical calendar, Eli Lilly placed a louder piece on the board: its next-generation weight loss drug retatrutide has cleared a crucial late-stage obesity trial.
The company said the results show significant weight loss across doses in patients with obesity. bringing Lilly one step closer to filing for approval of the weekly injection. called retatrutide. Lilly positioned the drug as different from existing shots and pills—both from Lilly and Novo Nordisk—and suggested it may be more effective.
In the late-stage Phase 3 trial, Lilly reported that the highest dose of retatrutide helped patients lose 28.3% of their weight—about 70.3 pounds—on average over 80 weeks. By contrast, the placebo group lost 2.2% over the same period when evaluating only patients who stayed on the drug.
Lilly said roughly 45% of the 2,500 patients in the Phase 3 trial achieved 30% or more weight loss. For patients with a BMI of 35 or above—Lilly said those participants are at higher risk of cardiovascular complications or diabetes—an extension of the study showed an average weight loss of 30.3% over 104 weeks using the highest dose.
That kind of number is exactly what is reverberating inside and outside the weight-loss market: Dan Skovronsky. Lilly’s chief scientific and product officer. described the 30% weight loss benchmark as an “incredible number to see. ” saying it has previously only been associated with bariatric surgery.
“We haven’t seen that level of weight loss before with these kinds of medicines,” Skovronsky told CNBC in an interview.
For Lilly. the trial results also offered an answer to a key question patients and doctors are still asking as GLP-1-based treatments spread: how many people will actually get below the obesity line. Lilly said around 65% of people taking the highest dose also achieved a BMI of less than 30—the threshold for obesity—at 80 weeks.
Lilly’s timing also matters because expectations were high. Ahead of the results, some analysts said they were expecting weight loss higher than what Lilly’s blockbuster weight loss drug Zepbound delivers, which is around 20% to 22%.
Side effects showed up in the data too, and not gently at the top dose. Lilly said retatrutide appeared to have higher rates of certain gastrointestinal side effects—such as nausea and diarrhea—especially at the highest dose. Still. the company said those rates were generally consistent with a previous Phase 3 trial on retatrutide in patients with obesity and a type of knee arthritis pain.
A lower dose in the new study was a counterweight: Lilly tested a 4-milligram dose not used in other trials, and said it was associated with fewer discontinuations due to side effects.
Skovronsky said the weight loss with the 4-milligram dose—19% on average, or 47.2 pounds, over 80 weeks—was similar to Zepbound at high doses. He also said it came with “a really excellent tolerability profile” that exceeded Lilly’s expectations.
Lilly added that about 4% of patients on the 4-milligram dose stopped the drug due to side effects, compared to nearly 5% with placebo. For the highest dose, Lilly said the discontinuation rate due to side effects was 11.3%.
Still, the company framed the dosing as a matter of matching outcomes to patients’ goals. Skovronsky said, “I think we’re making history here, both on the high end with the high dose and on the low dose for what we can offer patients.”
“For some patients, 30% weight loss may be more than what they’re seeking,” he added. “For other patients, that may be what they need to get healthy. So not everyone will go up to the highest dose level and stay on it for two years.”
Safety data, Lilly said, was consistent with other GLP-1-containing medications, with gastrointestinal effects leading the list. The highest dose was associated with nausea in around 42% of patients, diarrhea in roughly 32%, and constipation in 26.1%.
The company reported that more than 13% of patients on the highest dose experienced an upper respiratory tract infection. a contagious illness affecting the nose. sinuses. and throat. More than 12% also experienced dysesthesia, described by Lilly as an unpleasant nerve sensation observed in previous trials on retatrutide.
Cardiac and liver issues were also a focus before the results. Analysts had been watching to see whether retatrutide would cause cardiac issues such as arrhythmia. an irregular heartbeat—partly because Lilly said the drug works by targeting three gut hormones. including glucagon. which increases energy expenditure.
Lilly said it did not observe any cardiac or liver issues. The company did notice a slightly higher rate of urinary tract infections compared to placebo. and Skovronsky said most were mild and resolved while patients stayed on treatment. Lilly reported that more than 8% of patients at the highest dose had a UTI. Skovronsky said it was unclear why UTIs were higher. but that the side effect is also seen with bariatric surgery. so it may be the result of “the velocity of weight loss” people experience.
Retatrutide has been described by Lilly as a “triple G” drug because it targets GLP-1, GIP, and glucagon rather than just one or two like existing treatments. Lilly said this approach appears to have more potent effects on appetite and satisfaction with food than other treatments.
Beyond the trial itself, the results land in the middle of a fierce competition. Tirzepatide—the active ingredient in Zepbound—mimics GLP-1 and GIP, while Novo Nordisk’s semaglutide—the active ingredient in Wegovy—mimics only GLP-1.
Lilly said the trial data is the third late-stage result to date on retatrutide. The drug earlier this year succeeded in a diabetes trial and cleared a smaller study on patients with obesity and a type of knee arthritis in December.
Lilly is betting big on retatrutide as the next pillar of its obesity portfolio after Zepbound and newly launched pill, Foundayo. In a January note, TD Cowen analysts estimated retatrutide could rake in sales of $3.8 billion in 2030.
And it is not only about growth—it is about defending a lead. Lilly said retatrutide is critical to its plan to maintain its market share majority over Novo in the booming market for weight loss and diabetes drugs, which some analysts estimate could be worth about $100 billion by the 2030s.
At the same time, Novo is trying to close the gap. Lilly said it held a 60.1% share of the U.S. obesity and diabetes drug market in the first quarter, while Novo’s market share was 39.4%, based on an earnings presentation.
In March 2025. Novo said it agreed to pay up to $2 billion for the rights to an early experimental drug from the Chinese pharmaceutical company United Laboratories International. Lilly said Novo’s newly acquired drug could be a clear potential competitor to retatrutide because it similarly uses a three-pronged approach to promoting weight loss and regulating blood sugar. though Lilly said it is much earlier in development and will take several years before it reaches patients.
For now. the clearest immediate shift is on the trial scoreboard: retatrutide has passed a crucial late-stage test in obesity. with Lilly presenting results that show strong weight loss at both the highest dose and a new. lower 4-milligram dose—alongside side effects that appear heavier at the top end. but that Lilly says are generally consistent with what GLP-1 medicines already bring.
Eli Lilly retatrutide obesity trial Phase 3 weight loss weekly injection GLP-1 GIP glucagon Zepbound Foundayo Novo Nordisk semaglutide tirzepatide