Short answer: Retatrutide (LY3437943) is a triple hormone receptor agonist (GIP + GLP-1 + glucagon) developed by Eli Lilly for the treatment of obesity and type 2 diabetes. In a Phase 2 clinical trial published in NEJM, it produced an average weight loss of 24.2% over 48 weeks. However, retatrutide has NOT yet been approved by the FDA or the EMA. The drug is still in Phase 3 (TRIUMPH) trials. No retatrutide product sold on the market or online is legal or safe; buying or using it is strongly advised against.
What Is Retatrutide and How Does It Work?
Conventional GLP-1 medications generally work through a single or dual hormone mechanism:
- Wegovy and Ozempic (semaglutide): Stimulate only the GLP-1 receptors.
- Mounjaro and Zepbound (tirzepatide): Stimulate two receptors, GIP and GLP-1.
- Retatrutide ("Reta"): Has a triple (triple agonist) mechanism: GIP + GLP-1 + glucagon.
What Does Adding a Third Hormone (Glucagon) Change?
Stimulating the glucagon receptor speeds up fat burning in the liver and raises the basal metabolic rate (energy expenditure). As a result, it does not just suppress appetite; it also increases the number of calories the body burns.
Clinical Research Data: The NEJM Phase 2 Trial
Phase 2 results published in 2023 in the respected medical journal The New England Journal of Medicine (NEJM):
- Patient group: 338 adult participants with a body mass index (BMI) of 30 or above.
- 48-week result: In the highest-dose group, 12 mg, average body weight loss was 24.2% (about 26 kg, or 57 lb).
- Fatty liver: In participants who had fatty liver at the start, liver fat fell to the normal range (below 5%) at 24 weeks in 86% of those on the 12 mg dose (Sanyal et al., Nature Medicine 2024).
Retatrutide FDA Approval Process and Timeline
For a drug to move from clinical trials to prescription sales in pharmacies, it must fully complete all 3 phases and obtain regulatory approval:
| Stage | Status | Date |
|---|---|---|
| Phase 1 (Safety & dosing) | Completed | 2021 |
| Phase 2 (Efficacy & dose range) | Completed (published in NEJM) | 2023 |
| Phase 3 (TRIUMPH program) | Ongoing, results being reported | Ongoing |
| FDA & EMA marketing application | No approval anywhere yet | Check Eli Lilly and FDA announcements |
| Launch & prescription sales | Not approved | No confirmed date |
Retatrutide has not been approved anywhere yet. For its current status, check announcements from Eli Lilly and the FDA.
Critical Medical and Legal Warning: Why You Should Not Buy It
Products in vial or powder form have recently been seen for sale on websites, on social media and through illegal channels under names such as "Retatrutide Peptide" or "Research Chemical".
Health professionals and medical authorities give these vital warnings about such products:
- No license and no legal sale: No approved commercial retatrutide drug exists yet in any country in the world.
- Sterility and purity risk: Heavy metal residues, bacterial contamination and incorrect dosing have been found in these substances made in unregulated labs.
- Heart rate and arrhythmia risk: Glucagon receptor activation can cause temporary increases in heart rate. The long-term safety of this has not yet been established in Phase 3 trials. Using it without medical supervision can pose a life-threatening cardiac risk.
- Legal liability: Importing and selling unauthorized molecules is illegal.
Recommendation: During your weight-loss journey, choose only official medications that your doctor has prescribed and that are approved by the FDA or the EMA (Mounjaro, Wegovy, Ozempic, Saxenda and others).
Frequently asked questions
When will retatrutide be available in pharmacies?
Eli Lilly's Phase 3 TRIUMPH trials are ongoing and their results are being reported. Retatrutide has not been approved anywhere yet and there is no confirmed launch date; for its current status, check announcements from Eli Lilly and the FDA.
Is retatrutide more effective than Mounjaro?
According to Phase 2 data, retatrutide produced an average weight loss of 24.2%, while Mounjaro (tirzepatide) produced an average weight loss of 20.9% over 72 weeks. However, these results can only be confirmed once Phase 3 trials involving thousands of patients are completed.
Is it safe to take retatrutide right now?
No, it is definitely not safe. The drug has not been approved and cannot be sold legally. Forms sold online are unregulated and carry serious health risks.
Sources:
- Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial. N Engl J Med 2023; 389:514-526. DOI: 10.1056/NEJMoa2301972
- U.S. National Library of Medicine. TRIUMPH-1 ClinicalTrials.gov Identifier: NCT05929066
- Sanyal AJ, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med 2024
