Frequently Asked Questions
This has been medically reviewed. Last updated: June 2026.
1. What is retatrutide?
Retatrutide is an investigational once-weekly triple hormone receptor agonist. Retatrutide is a single molecule that activates the body's receptors for glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon.
In clinical trials, retatrutide is taken as a once-weekly subcutaneous injection.
2. Where can you get retatrutide?
Retatrutide is not yet available for public use. Lilly is currently studying retatrutide in Phase 3 clinical trials for obesity, type 2 diabetes, knee osteoarthritis pain, moderate-to-severe obstructive sleep apnea (OSA), chronic low back pain, cardiovascular and renal outcomes, and metabolic dysfunction-associated steatotic liver disease (MASLD).
3. Is it safe to take retatrutide?
Retatrutide is an investigational molecule available only to participants in Lilly's clinical trials, where its safety and efficacy are still being evaluated. It has not been approved by any regulatory agency, and no one should take anything claiming to be retatrutide outside of a Lilly-sponsored clinical trial. Illicit retatrutide products may contain unknown ingredients, harmful contaminants and impurities. These products may also have too much or too little active ingredient, or the wrong ingredient entirely. Lilly continues to warn the public about the dangers of unapproved drugs.
4. Has retatrutide been studied in obesity and other conditions?
In May 2026, Lilly announced TRIUMPH-1 (Phase 3) topline results for retatrutide in adults with obesity or overweight and at least one weight-related comorbidity and without diabetes. The study also included subsets of adults who had knee osteoarthritis pain or moderate-to-severe OSA, allowing retatrutide to be studied simultaneously across all three conditions under a master protocol with two separate basket studies.1,2 These data were presented at the 2026 American Diabetes Association’s (ADA) annual meeting.
Phase 2 trial results for retatrutide and obesity were presented at the 2023 ADA annual meeting and were published in the New England Journal of Medicine.3 TRIUMPH-4 (Phase 3) topline results that evaluated retatrutide for the treatment of obesity and knee osteoarthritis pain were released in December 2025.4
5. When was data on retatrutide and type 2 diabetes announced?
Lilly announced Phase 3 topline results for retatrutide in adults with type 2 diabetes in March 2026.5
In June 2026, Lilly announced full Phase 3 results from TRANSCEND-T2D-1 in adults with type 2 diabetes, with findings also presented at the American Diabetes Association (ADA) 86th Scientific Sessions and simultaneously published in The Lancet.2
6. What is a GLP-3?
The term “GLP-3” is a scientifically inaccurate label used informally in the media to describe triple hormone receptor agonists, such as Lilly’s retatrutide. This nickname emerged because the medication simultaneously targets three receptors, GLP-1, GIP, and glucagon, rather than representing an actual scientific classification.
A more suitable term to describe retatrutide is “triple agonist,” which accurately reflects the mechanism of action.
7. What company is developing retatrutide?
Lilly is developing retatrutide.
8. Is retatrutide approved by the FDA?
No. Retatrutide is not currently approved by the FDA and is considered an investigational medication. Lilly is currently evaluating its safety and efficacy in clinical trials.
9. When will retatrutide be available to the public?
Retatrutide is currently in Phase 3 clinical trials, and launch will depend on the completion of these trials and the regulatory approval process.
Retatrutide has not been approved by any regulatory agency and is legally available only through Lilly's clinical trials. Anything sold to consumers outside of those trials is illegal, with no way to verify its safety, purity, or dosing. Taking unregulated substances poses serious health risks, and Lilly continues to work with law enforcement and regulatory authorities to combat black market drugs.
10. How much will retatrutide cost?
Upon completion of clinical trials and the regulatory review process, we plan to ensure retatrutide is priced to reflect the overall value to the healthcare system. Our goal is to make our medicines available and accessible to people who need them.
11. Which phase is retatrutide in?
Retatrutide has successfully completed three Phase 3 clinical trials:
- TRIUMPH-4 in adults with obesity or overweight and knee osteoarthritis pain, and without diabetes.4
- TRIUMPH-1 in adults with obesity or overweight and at least one weight-related comorbidity and without diabetes.1,2
- TRIUMPH-1 included two basket sub-studies, 1) in patients with knee osteoarthritis pain and 2) in patients with moderate to severe obstructive sleep apnea
- TRANSCEND-T2D-1 in adults with type 2 diabetes and inadequate glycemic control with diet and exercise alone.2,5
Additional trials in the TRIUMPH and TRANSCEND-T2D program are underway to evaluate retatrutide’s efficacy and safety in obesity and overweight with at least one weight-related co-morbidity, type 2 diabetes, moderate-to-severe obstructive sleep apnea, chronic low back pain, established cardiovascular disease, existing chronic kidney disease, and metabolic dysfunction-associated steatotic liver disease.
References:
- Eli Lilly & Company. (May 21, 2026). Lilly’s triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial. PR Newswire. https://www.prnewswire.com/news-releases/lillys-triple-agonist-retatrutide-delivered-powerful-weight-loss-in-pivotal-phase-3-obesity-trial-302778859.html
- Eli Lilly & Company. (June 6, 2026). Lilly’s triple agonist, retatrutide, drove substantial improvements in weight, A1C, knee osteoarthritis pain, and obstructive sleep apnea, demonstrating its remarkable potential to treat obesity and its complications. PR Newswire. https://www.prnewswire.com/news-releases/lillys-triple-agonist-retatrutide-drove-substantial-improvements-in-weight-a1c-knee-osteoarthritis-pain-and-obstructive-sleep-apnea-demonstrating-its-remarkable-potential-to-treat-obesity-and-its-complications-302793169.html
- Eli Lilly & Company. (June 26, 2023). Lilly’s phase 2 retatrutide results published in The New England Journal of Medicine show the investigational molecule achieved up to 17.5% mean weight reduction at 24 weeks in adults with obesity and overweight. PR Newswire. https://www.prnewswire.com/news-releases/lillys-phase-2-retatrutide-results-published-in-the-new-england-journal-of-medicine-show-the-investigational-molecule-achieved-up-to-17-5-mean-weight-reduction-at-24-weeks-in-adults-with-obesity-and-overweight-301863690.html
- Eli Lilly & Company. (December 11, 2025). Lilly's triple agonist, retatrutide, delivered weight loss of up to an average of 71.2 lbs along with substantial relief from osteoarthritis pain in first successful Phase 3 trial. PR Newswire. https://www.prnewswire.com/news-releases/lillys-triple-agonist-retatrutide-delivered-weight-loss-of-up-to-an-average-of-71-2-lbs-along-with-substantial-relief-from-osteoarthritis-pain-in-first-successful-phase-3-trial-302638804.html
- Eli Lilly & Company. (March 19, 2026). Lilly’s triple agonist, retatrutide, demonstrated significant reductions in A1C and weight in first Phase 3 trial for treatment of type 2 diabetes. PR Newswire. https://www.prnewswire.com/news-releases/lillys-triple-agonist-retatrutide-demonstrated-significant-reductions-in-a1c-and-weight-in-first-phase-3-trial-for-treatment-of-type-2-diabetes-302718589.html