Retatrutide may cut weight and offer other health benefits
Retatrutide, dubbed the 'Godzilla' of weight-loss drugs, cut body weight by roughly a quarter in late-stage trials while also improving blood sugar, inflammation markers, and other cardiometabolic risks, researchers reported. The experimental Eli Lilly triple-hormone drug is not yet approved by any regulator.
Key Takeaways
- In an 80-week diabetes trial, weekly retatrutide cut average body weight by up to about 19%, with nearly a third on the highest dose losing at least 25%.
- A separate obesity trial found average losses of about 25% at 80 weeks and 30% at 104 weeks on the top dose.
- The drug also improved blood sugar, blood pressure, lipids, and inflammation markers, with mostly gastrointestinal side effects.
- Eli Lilly has not yet sought regulatory approval; it says it plans to file early next year.
What did the latest retatrutide trials find?
According to The Guardian, the largest study of its kind found retatrutide could improve blood sugar, reduce inflammation, and cut body weight by a quarter. Findings from an Eli Lilly-funded phase 3 trial in people with obesity and type 2 diabetes were published in The Lancet and presented at the European Association for the Study of Diabetes meeting in Milan.
The randomised, double-blind, placebo-controlled study enrolled 2,047 adults across eight countries. Participants had a BMI of 27 or above and type 2 diabetes; about half were women, and the average age was 55. After 80 weeks, average weight loss was 11.9% on 4 mg, 16.8% on 9 mg, and 18.8% on 12 mg, versus 5.1% on placebo.
On the 12 mg dose, 47% lost at least 20% of starting weight and 31% lost at least 25%, compared with 6% and 3% on placebo. NBC News reported people with type 2 diabetes lost up to about 60 pounds, described as the largest weight loss yet seen in a diabetes drug trial. A separate New England Journal of Medicine obesity trial found average losses of about 25% after 80 weeks and 30% after 104 weeks on the highest dose.
How does retatrutide work differently from other drugs?
Retatrutide mimics three gut hormones—GLP-1, GIP, and glucagon—that help control appetite, blood sugar, and metabolism. Unlike Wegovy, which mainly targets GLP-1, or Mounjaro, which pairs GLP-1 with GIP, retatrutide also engages the glucagon receptor, which researchers say helps increase energy expenditure.
Beyond weight, 72% of diabetes-trial participants on retatrutide reached an HbA1c of 6.5% or lower, versus 29% on placebo. NBC News said A1C fell by up to 1.6%, and up to 40% reached levels below 5.7%. Researchers also reported improvements in blood pressure, lipid profiles, and high-sensitivity C-reactive protein. Ars Technica reported knee pain reductions of up to 62% and sleep apnea event drops of up to 57% in trial subsets.
What are the side effects, and is it approved?
The most common adverse events were gastrointestinal. Diarrhoea occurred in 27–34% of retatrutide patients versus 13% on placebo, and nausea in 14–28% versus 8%. About 8% on the highest dose stopped treatment, versus about 5% on placebo. Seven deaths in the diabetes trial were judged unrelated to the drug.
Retatrutide is not approved by any regulatory agency. Lilly plans to seek approval early next year, NBC News reported. For more BlasterPost investigations into contested claims and unresolved public questions, see our True Crime & Unsolved Mysteries hub.