What Is Retatrutide?
What Is Retatrutide?
Retatrutide (development code LY3437943) is an investigational once-weekly injection being developed by Eli Lilly for obesity, type 2 diabetes, and related metabolic conditions. It is not yet approved by the FDA or any other regulator (FDA).
It is sometimes called "reta" or "Triple G" in online communities. Note: "retaglutide" is not a separate drug — it's a misspelling/synonym of retatrutide that appears in some chemical-supplier catalogs. The official generic name is retatrutide.
How it works: a "triple agonist"
Retatrutide is a triple hormone receptor agonist — it activates three receptors at once:
- GLP-1 (glucagon-like peptide-1) — the same target as Ozempic/Wegovy (semaglutide)
- GIP (glucose-dependent insulinotropic polypeptide) — the second target of Mounjaro/Zepbound (tirzepatide)
- Glucagon — the third receptor, which is what makes retatrutide unique
The glucagon arm is the new piece. It's thought to increase energy expenditure and fat oxidation, which is why retatrutide's weight-loss numbers in trials have come in higher than the currently approved GLP-1 drugs (Lilly).
The trial results so far
Retatrutide is in Phase 3 clinical trials (the TRIUMPH program). In TRIUMPH-1 (a trial of 2,339 adults with obesity but not diabetes), participants on the 12 mg dose lost an average of 28.3% of body weight at 80 weeks, compared to 2.2% on placebo. In people with more severe obesity who completed the trial, weight loss reached roughly 30% (about 85 lbs) at 104 weeks (Lilly; GLP-3 Wiki).
For comparison, currently approved GLP-1 drugs typically produce around 15–20% weight loss — so retatrutide's results rival bariatric surgery outcomes.
Who makes it and when is it available?
Retatrutide is being developed by Eli Lilly. It is not available by prescription anywhere and cannot legally be compounded. The FDA states it is "legally available only to participants in [Lilly's] clinical trials" (FDA). See our article on the approval timeline and on legality for more.
Retawiz provides educational information only and is not medical advice. Retatrutide is investigational and not FDA-approved. Retawiz does not sell, source, or recommend any medication. Consult a licensed clinician for any medical decision.