What Is Retatrutide?
Retatrutide is a triple receptor agonist developed by Eli Lilly that targets three hormone receptors simultaneously:
- GLP-1 (glucagon-like peptide-1) — reduces appetite and slows gastric emptying
- GIP (glucose-dependent insulinotropic polypeptide) — enhances insulin sensitivity and fat metabolism
- Glucagon — actively increases energy expenditure and fat oxidation
This triple mechanism goes beyond what current medications offer. While semaglutide targets GLP-1 alone and tirzepatide targets GLP-1 plus GIP, retatrutide adds the glucagon component — and that addition is significant.
Why the Glucagon Receptor Matters
The glucagon receptor activation is what sets retatrutide apart. The GLP-1 and GIP components primarily work by reducing calorie intake (appetite suppression, slower digestion). The glucagon component adds something entirely new: it actively increases calorie burning.
Glucagon receptor activation:
- Stimulates energy expenditure (your body burns more calories at rest)
- Promotes fat oxidation (preferentially burning stored fat for fuel)
- May help preserve lean muscle mass relative to fat loss
This dual approach — eat less AND burn more — is why retatrutide has produced the highest weight loss numbers ever seen in clinical trials.
Clinical Results
Phase 2 Trial (NEJM, 2023)
The Phase 2 trial published in the New England Journal of Medicine demonstrated 24.2% total body weight loss at 48 weeks at the highest dose — results that generated enormous excitement in the medical community.
TRIUMPH-4 (Phase 3, December 2025)
The Phase 3 TRIUMPH-4 trial confirmed and exceeded the Phase 2 results:
| Dose | Weight Loss at 68 Weeks |
|---|---|
| 9 mg | 26.4% |
| 12 mg | 28.7% |
At the 12 mg dose, 28.7% weight loss makes retatrutide potentially the most effective weight loss medication ever studied in a Phase 3 clinical trial. For a 250-pound patient, that would translate to approximately 72 pounds.
Dosing
Retatrutide is administered as a once-weekly subcutaneous injection, similar to tirzepatide and semaglutide. The exact dose escalation schedule for the commercial product will be determined pending FDA review, but clinical trials used a gradual titration to minimize side effects.
Side Effects
The side effect profile is similar to other GLP-1 medications:
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Decreased appetite
At higher doses, GI side effects may be slightly more frequent, but the gradual dose escalation helps most patients tolerate the medication.
FDA Status
Retatrutide is currently in Phase 3 clinical trials. Eli Lilly has not confirmed a specific NDA filing timeline, but the program is progressing. Approval is likely still at least 1-2 years away.
Important: Retatrutide Is NOT Currently Available
Retatrutide is not available through any legitimate channel today. It cannot be obtained from:
- Any retail or specialty pharmacy
- Any compounding pharmacy
- Any telehealth provider
- Any online source
Any product being sold as "retatrutide" is not an FDA-approved medication and has not been verified for safety, purity, or potency. Patients should wait for FDA approval before seeking this medication.
Valitide and Retatrutide
Valitide is closely monitoring the clinical development of retatrutide and will offer it as a treatment option once it receives FDA approval. In the meantime, our providers can prescribe currently approved GLP-1 and dual-agonist medications that are available today.