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Retatrutide

Triple GIP / GLP-1 / glucagon agonist · often called GLP-3
What it is

Retatrutide is a lab-made triple agonist at the GIP, GLP-1 and glucagon receptors, often called GLP-3.[1][2] That nickname is not a real hormone; there is no GLP-3 hormone, and the real GLP-2 is a separate gut peptide.[3]

Origin: First described in 2022 by Coskun and colleagues at Eli Lilly in Indianapolis as LY3437943, a triple agonist at the glucagon, GIP and GLP-1 receptors.[1]

What researchers study it for

Research areas

Human trials and animal work have focused on metabolic outcomes.

  • Body-weight reduction in adults with obesity, including a phase 2 trial and the phase 3 TRIUMPH-1 trial[2][4][5]
  • Blood sugar and metabolic effects in early clinical work and animal studies[1]
  • Energy use in obese mice, where glucagon-receptor activity added to GIP- and GLP-1-driven effects on intake[1]
  • Knee osteoarthritis pain and obstructive sleep apnea measures as co-primary outcomes in TRIUMPH-1 subgroups[4]

Evidence level

Level 4 of 4: Large human trialsTRIUMPH-1 randomized 2,339 adults with obesity without diabetes in a phase 3 trial, after a 338-person phase 2 obesity trial.[2][4][5][6]

Why so few human trials?

Cautions

Studies and regulators point to several reasons for care.

  • Retatrutide is investigational and is not FDA approved for any use[7]
  • FDA states that retatrutide has not been found safe and effective for any condition[7]
  • Gastrointestinal side effects were among the main tolerability findings in the phase 2 obesity trial[2]

Retatrutide is not FDA approved.[7]

Also called

Retatrutide goes by several names.

  • LY3437943, its lab code[1][2]
  • Triple GIP, GLP-1 and glucagon receptor agonist[1][4]
  • Often called GLP-3 (nickname only; there is no GLP-3 hormone)[3]

Good to know

In obese mice, adding glucagon-receptor activity increased energy expenditure on top of the calorie-intake effects from GIP and GLP-1 receptor activity.[1]

Handling

Storage basics General

These general basics apply to most freeze-dried research peptides.

Most research peptides come as a freeze-dried powder in a sealed vial
Unmixed vials are generally kept cold, dry, and away from light
Mixed solutions are generally refrigerated, since they are less stable than the dry powder
Peptides 101For mixing basicsNPL Dose CalculatorTo work out concentration after mixing
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Sources and studies

These studies and official pages are the research behind this profile.