A Study of Retatrutide (LY3437943) Compared to Tirzepatide (LY3298176) in Adults Who Have Obesity

What Was Tested

In this phase 3 trial, researchers set out to test Retatrutide and Tirzepatide.

The study will last about 89 weeks.

It had two arms (groups): Retatrutide (experimental) and Tirzepatide (active comparator).

Participants will receive retatrutide administered subcutaneously (SC).

Participants will receive tirzepatide administered SC.

The registry classes the interventions as drug.

Who Took Part

The registry lists 800 planned participants were the target.

It was open to people of any sex aged from 18 years with no upper age limit.

Healthy volunteers were not accepted; participants needed the condition being studied.

The full record lists 1 inclusion and 13 exclusion criteria; among the exclusions: have a self-reported change in body weight \>5 kilograms (kg) (11 pounds) within 90 days before screening; have a prior or planned surgical treatment for obesity; have a prior or planned endoscopic procedure and/or device-based therapy for obesity.

How the Study Was Run

It was run as a randomized, parallel-group and double-blind study.

The participants were allocated by chance, so the Retatrutide group and the comparison group should start out alike.

The Retatrutide group and the comparison group ran side by side rather than switching.

Neither the participants nor the staff measuring them knew who was on Retatrutide, so expectations could not easily colour the readings.

Those kept unaware of assignments: participant and investigator.

It started in 2024-11-01 with completion listed for 2026-11.

It ran at 65 sites in United States (40), Poland (10), Germany (9), Argentina (5) and Puerto Rico (1).

Its stated primary purpose is treatment.

What Was Measured

Primary outcome: Percent Change from Baseline in Body Weight (time frame: Baseline, Week 80).

It also tracked 9 secondary outcomes, for example Change from Baseline in Body Mass Index (BMI), Change from Baseline in Waist Circumference, Percent Change from Baseline in Total Cholesterol, Percent Change from Baseline in Triglycerides, Change from Baseline in Systolic Blood Pressure (SBP) and Change from Baseline in Diastolic Blood Pressure (DBP).

What This Means in Plain Language

Put simply, this is a phase 3, randomized trial of Retatrutide and Tirzepatide in 800 people.

With 800 participants it is a large trial for this field.

Its status is active not recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Retatrutide compound page and the Tirzepatide compound page, all human trials.