Retatrutide has positive phase 3 results, but it is not approved. Lilly has reported topline results from four pivotal TRIUMPH trials and says it intends to submit a U.S. application in the first quarter of 2027. As of 20 September 2026, there is no FDA approval, no approved product and no approved retatrutide dosage schedule.
Retatrutide phase 3 results at a glance
The highest-dose efficacy estimate ranged from 20.8% to 28.7% mean weight reduction across the four announced TRIUMPH trials. The populations, durations and endpoints differ, so the rows are a status summary—not a head-to-head ranking.
Efficacy-estimand figures reported by the sponsor. A treatment-regimen estimate, adverse-event analysis and complete protocol context are needed to interpret each trial fully.
What did TRIUMPH-1 show?
TRIUMPH-1 enrolled 2,335 adults with obesity or overweight and at least one weight-related condition, without type 2 diabetes. ClinicalTrials.gov records it as completed in April 2026. Lilly reported mean weight changes at week 80 of 19.0%, 25.9% and 28.3% at 4, 9 and 12 mg, respectively, compared with 2.2% on placebo under the efficacy estimand.
The 4 mg arm matters because it prevents the result from collapsing into one maximum-dose headline: it used only one escalation step and had a lower reported discontinuation rate due to adverse events than placebo. The 12 mg arm produced the largest mean change, while 45.3% of participants reached at least 30% weight loss in the sponsor's analysis.
What did TRIUMPH-2 and TRIUMPH-3 add?
TRIUMPH-2 tested adults with type 2 diabetes, a population that generally loses less weight in incretin trials. Lilly reported mean losses of 12.7%, 19.1% and 20.8% at 4, 9 and 12 mg over 80 weeks, alongside mean A1C reductions of up to 1.6 percentage points.
TRIUMPH-3 enrolled adults with severe obesity and established cardiovascular disease, with or without type 2 diabetes. The reported 80-week means were 21.6% at 9 mg and 22.6% at 12 mg, against 3.2% for placebo. A trial in a higher-risk population answers a different question from a general obesity study; it does not make either percentage more directly transferable to an individual.
What did TRIUMPH-4 show?
TRIUMPH-4 studied obesity or overweight with knee osteoarthritis and had two co-primary outcomes: body weight and knee pain. At week 68, Lilly reported mean weight changes of 26.4% at 9 mg and 28.7% at 12 mg, compared with 2.1% on placebo. WOMAC pain scores improved by 4.5 and 4.4 points in the two retatrutide groups, versus 2.4 points on placebo.
That unusually large placebo pain response is part of the result, not noise to omit. It also shows why the weight figure cannot stand in for the whole trial: TRIUMPH-4 was designed to test a complication of obesity as well as weight change.
Does phase 3 success mean FDA approval is next?
It means an application may be supportable; it does not mean approval has happened. Lilly says the data package supports global submissions and that it plans a U.S. Biologics License Application in the first quarter of 2027. The FDA would then review manufacturing, effectiveness, safety, labelling and the proposed benefit-risk balance. A company timeline is not an FDA decision or an approval date.
Outcome research also continues. Large cardiovascular and kidney outcome trials answer questions that a weight-loss endpoint cannot. Until a regulator approves a product, there is no label, no retail presentation and no approved prescribing schedule.
What is the phase 3 retatrutide dosing schedule?
The announced trials studied once-weekly target doses under protocol-controlled escalation. Those numbers describe how screened participants were treated and monitored; they are not a public dosing chart. The distinction matters because the phase 2 trial linked faster escalation with more gastrointestinal adverse events, and phase 3 protocols allowed specific management steps that a retail vial does not reproduce.
The retatrutide dosage calculator therefore keeps two jobs separate: it can calculate concentration and syringe volume for a number entered by the user, while its dosage chart labels every figure as a study amount. It does not select a dose.
Can phase 3 retatrutide be bought now?
No approved phase 3 product is on sale. A vial advertised as “retatrutide,” “reta” or “GLP-3R” is not a compounded version of an approved medicine because there is no approved medicine to compound. In an August 2026 warning letter, the FDA treated retail retatrutide as an unapproved new drug and rejected “research use only” wording when the surrounding marketing showed intended human use.
The practical status is therefore simple: investigational, even after successful phase 3 readouts. Results, submission and approval are three separate milestones, and retatrutide has reached only the first.