A study testing whether a new weekly shot from Lilly, retatrutide, can help with weight.

Who can join

Adults 18+, have obesity, BMI 27+.

What you take

retatrutide, given as part of the study at no cost to you. Some participants may receive a placebo (an inactive version) instead, decided at random.

How long it lasts

The full study runs about 2.8 years; your own time in it is usually shorter.

What you get

The study medication and study-related care at no cost. Compensation varies by study site; many cover travel and provide the study medication at no cost. The trial coordinator will explain what that site offers before you join.

What this study is for

Full study title: A Study of Retatrutide (LY3437943) in Participants Without Type 2 Diabetes Who Have Obesity or Overweight.

Primary condition: Obesity. Also studied in: Overweight.

Who can join, in detail

Key inclusion criteria

• Have a Body Mass Index (BMI) at screening
• >= 30 kilogram per square meter (kg/m2) OR
• >= 27 kg/m2 with presence of at least one of the following weight-related conditions at screening: high blood pressure, abnormal levels of lipid, obstructive sleep apnea, heart disease
• Have at least one unsuccessful attempt to lose weight by dieting

Key exclusion criteria

• 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 type 1 diabetes or type 2 diabetes
• Have a family or personal history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN-2)
• Have had within the past 90 days before screening:

Where this study is enrolling

This trial has 20 US sites across 14 states. Contact the site coordinator directly to start the screening process.

Timeline

Started enrolling: 2026-01-24. Expected completion: 2028-11. Last updated on ClinicalTrials.gov: 2026-05-22.

Official source

We sync this data quarterly from ClinicalTrials.gov, the federal registry for clinical research. Before contacting a site, verify the trial is still recruiting on the official page:

View on ClinicalTrials.gov →

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