Retatrutide

What is Retatrutide

Retatrutide (LY3437943) is an investigational synthetic peptide being developed by Eli Lilly. It is designed as a triple hormone-receptor agonist, activating the receptors for glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon. Unlike approved GLP-1-based medicines, retatrutide is designed to engage all three pathways in a single molecule.

Retatrutide has a reported half-life of approximately six days, supporting its investigation as a once-weekly treatment.

What it is researched for

Research has primarily focused on retatrutide’s potential role in:

• Obesity and overweight with weight-related conditions
• Type 2 diabetes and metabolic health
• Knee osteoarthritis associated with obesity
• Moderate-to-severe obstructive sleep apnea
• Cardiovascular and renal outcomes
• Metabolic dysfunction-associated steatotic liver disease (MASLD)
• Chronic low back pain

These areas remain under clinical investigation, and research findings should not be interpreted as proof of safety or effectiveness for individual use.

Available public research and general information

Retatrutide has been evaluated in multiple clinical studies. In a 48-week Phase 2 obesity trial published in the New England Journal of Medicine, participants receiving the highest studied dose had a mean body-weight reduction of 24.2%, compared with 2.1% with placebo. Gastrointestinal adverse events were among the most commonly reported effects and were generally mild to moderate.

A separate Phase 2 study in people with type 2 diabetes evaluated retatrutide against placebo and active treatment and reported improvements in body weight and several metabolic measures.

As of 2026, retatrutide remains investigational and has not been approved for public use by a regulatory agency. Lilly continues to evaluate it in Phase 3 clinical trials.

Reconstitution information

Retatrutide used in clinical research is supplied and administered according to the study protocol. Because retatrutide is not an approved medicine, there is no universally established public reconstitution standard for products sold outside legitimate clinical research.

For research materials, users should follow the applicable laboratory protocol, supplier documentation, validated handling procedures, and institutional requirements. Avoid presenting an unofficial dilution, mixing volume, concentration, or injection protocol as an established medical instruction.

Other relevant product details

• Compound name: Retatrutide
• Development code: LY3437943
• Classification: Investigational peptide / triple hormone-receptor agonist
• Primary targets: GIP, GLP-1, and glucagon receptors
• Developer: Eli Lilly and Company
• Investigational route: Subcutaneous administration in clinical trials
• Research status: Phase 3 development
• Regulatory status: Not approved for public use as of 2026
• Research considerations: Authenticity, purity, identity, sterility, and appropriate analytical documentation are important when evaluating research materials.

Products represented as retatrutide outside authorized clinical research may have uncertain identity, purity, potency, sterility, or contamination risk. Lilly specifically warns that unapproved products claiming to contain retatrutide may contain incorrect or unknown ingredients.

Research-use disclaimer: This information is provided for educational and research-information purposes only. Retatrutide is investigational and should not be represented as an approved treatment or as a recommendation for human use.