What is retatrutide? The experimental drug transforming weight loss

By now, very few people haven’t heard of Ozempic. Originally developed to treat type 2 diabetes by mimicking hormones that regulate blood sugar, the medication quickly became better known for its powerful impact on weight loss due to the way the same mimicking hormones affect appetite.

But while Ozempic is arguably the most recognizable drug in its class, it isn’t the only medication approved for weight management. Others include Wegovy and Saxenda, while newer drugs like tirzepatide (sold as Mounjaro and Zepbound) work through related hormonal pathways.

Now, additional drugs are generating even greater attention, with retatrutide dominating conversations and clinical trials alike, despite the medication not yet approved by the U.S. Food and Drug Administration (FDA). “Retatrutide is still under investigation, and long-term safety, dosing and side-effect profiles are still being evaluated,” says Dr. John Burns, a board-certified plastic surgeon and the president at Dallas Plastic Surgery Institute.

Here’s what researchers currently know about the drug, how it works and how it differs from existing weight management medications.

Retatrutide is an experimental injectable weight-loss medication being developed by the pharmaceutical company Eli Lilly. “It is sometimes referred to as a ‘triple-agonist’ medication because it targets three key metabolic hormone receptors involved in appetite control and energy balance,” explains Burns.

Dr. Alison Mitzner, a board-certified physician based in New York City, says it has advanced through early- and mid-stage clinical trials and is currently being evaluated in large Phase 3 studies. This is typically the final stage of testing before a drug can be submitted for regulatory approval.

Interest in the drug surged after a 2023 clinical trial reported substantial weight loss among adults with obesity.

But researchers are also studying the drug’s effects on broader metabolic health, including blood sugar regulation, cholesterol levels and cardiovascular risk markers. That’s because obesity is closely linked to conditions such as type 2 diabetes, heart disease and fatty liver disease, so treatments that produce significant weight loss may also improve these related health risks.