Retatrutide is still investigational in October 2026. What the published phase 3 trials (TRIUMPH-2, TRANSCEND-T2D-1) and the phase 2 obesity trial found, including side effects.
Last checked 6 min read · 4 sources No paid links in this article Education, not medical advice
No. As of October 9, 2026, retatrutide is an investigational drug from Eli Lilly with no FDA approval. Published phase 3 trials report average weight loss of up to 18.8% at 80 weeks in adults with obesity and type 2 diabetes (versus 5.1% with placebo), with more stomach side effects than placebo.
No. As of October 9, 2026, retatrutide has no FDA approval; it remains under investigation by Eli Lilly for obesity, type 2 diabetes, knee osteoarthritis and obstructive sleep apnea (TRIUMPH design paper). We found no retatrutide entry in FDA’s approved-drug data.
It works on three hormone receptors (GIP, GLP-1 and glucagon). Two phase 3 trials have been published, both in people with type 2 diabetes. Evidence: A for weight and blood-sugar change in trials; long-term safety is not yet known.
| Trial | Who | Length | Weight change | Placebo |
|---|---|---|---|---|
| Phase 2 obesity (NEJM 2023) | 338 adults with obesity | 48 weeks | −8.7% (1 mg) to −24.2% (12 mg) | −2.1% |
| TRIUMPH-2 (Lancet 2026) | 1,152 adults with obesity and type 2 diabetes | 80 weeks | −11.9% (4 mg), −16.8% (9 mg), −18.8% (12 mg) | −5.1% |
| TRANSCEND-T2D-1 (Lancet 2026) | 537 adults with type 2 diabetes on diet and exercise | 40 weeks | −11.5% (4 mg) to −15.3% (12 mg); HbA1c −1.69% to −1.94% | −2.6%; HbA1c −0.81% |
Sources: Jastreboff 2023, TRIUMPH-2, TRANSCEND-T2D-1. For how this compares with approved drugs, see retatrutide vs tirzepatide.
Recruiting now: 2 open registrations for retatrutide in the Trial Finder.
In TRIUMPH-2, diarrhea affected 27–34% of people on retatrutide versus 13% on placebo, and nausea 14–28% versus 8%. Low blood pressure and dysesthesia (abnormal skin sensations) were more common with retatrutide, and stopping treatment because of adverse events or death was more frequent at 9 mg (12%) and 12 mg (8%) than with placebo (5%) (TRIUMPH-2).
The phase 2 trial reported dose-related stomach side effects and heart-rate increases that peaked at 24 weeks (Jastreboff 2023). More on the drug: retatrutide reference page. Approved drugs in the same family include tirzepatide and semaglutide.
No. As of October 9, 2026 it is an investigational drug with no FDA approval.
In TRIUMPH-2, adults with obesity and type 2 diabetes lost 11.9% to 18.8% of body weight at 80 weeks depending on the dose, versus 5.1% with placebo. In the phase 2 obesity trial, the 12 mg group lost 24.2% at 48 weeks.
Mostly stomach effects such as diarrhea and nausea. TRIUMPH-2 also reported more low blood pressure and dysesthesia than placebo, and the phase 2 trial reported heart-rate increases that peaked at 24 weeks.
Not necessarily. Products sold online are not FDA-approved and are not the drug supplied in Lilly’s trials, so their identity and purity are unknown.
Medical Disclaimer: This is general education, not medical advice. Researched and written by Kymata Health Editorial; sources cited inline. Retatrutide is an investigational drug. Doses are described only as what a trial gave. Products sold online as retatrutide are not the drug tested in these trials. Evidence grades: A = several randomized trials or a meta-analysis; B = at least one randomized trial; C = small or pilot human data, expert consensus, or mechanism only; D = animal or cell data, or anecdote.