Retatrutide is not FDA approved as of September 2026. Five Phase 3 TRIUMPH trials have reported positive results and Lilly plans to file a Biologics License Application in Q1 2027, which puts an FDA decision no earlier than late 2027 and more likely in 2028. Here is the timeline, what the trials showed, and what approval would change.
Retatrutide is not FDA approved for any indication and is not available on prescription. Phase 3 results are in for TRIUMPH-1 (−28.3% body weight at 80 weeks on 12mg), TRIUMPH-2 (−20.8%), TRIUMPH-3 (−22.6%), TRIUMPH-4 (−28.7% at 68 weeks) and TRANSCEND-T2D-1. Lilly has said it will submit a Biologics License Application in the first quarter of 2027; the FDA has set no date. Research-grade retatrutide is sold by suppliers such as Purgo Labs for laboratory research only.
Safety, tolerability, and PK/PD in healthy volunteers. Dose-ranging established.
NCT04881760: ~24% weight loss at 48 weeks (n=338). Highest Phase 2 obesity result ever recorded.
Five positive readouts so far: TRIUMPH-4 (Dec 2025, −28.7% at 68 wks), TRIUMPH-1 (May 2026, −28.3% at 80 wks), TRIUMPH-2 (−20.8%), TRIUMPH-3 (−22.6%), TRANSCEND-T2D-1. Sleep-apnoea, MASLD and cardiovascular-outcomes trials still reading out.
Lilly said on 23 July 2026, and again on 5 August, that it will file a Biologics License Application in the first quarter of 2027 once manufacturing (CMC) data is complete. An earlier 2026 filing target was pushed back.
Standard review: about 10–12 months from acceptance. Priority review: about 6 months. No designation announced.
Earliest realistic decision on the obesity indication. Sleep apnoea and knee-osteoarthritis pain are in the same package per Lilly; T2D and cardiovascular indications would follow.
Research use only. Compound Review scores vendors on documentation — laboratory certificates, lot records, pricing and company identity. Nothing on this page is guidance on human or veterinary use, dosing or health outcomes.
The Phase 3 TRIUMPH (TRIple hormone receptor agonist for Unmet Medical need in Patients with Obesity and Metabolic conditions with High cardiovascular risk) program is Eli Lilly's pivotal trial program for retatrutide. Phase 3 is the final stage before a marketing application — Lilly intends a BLA — and the trials must demonstrate both efficacy and long-term safety in large, diverse populations.
For the obesity indication the FDA's efficacy bar is at least 5% greater weight loss than placebo and at least 35% of participants losing 5% or more. The TRIUMPH readouts clear that by a wide margin: TRIUMPH-1 (May 2026) reported −28.3% at 80 weeks on 12mg, −25.9% on 9mg and −19.0% on 4mg, with 45% of 12mg participants losing 30% or more; TRIUMPH-4 (December 2025) reported −28.7% at 68 weeks in adults with knee osteoarthritis; TRIUMPH-2 and -3 reported −20.8% and −22.6%. The open questions are tolerability at the top dose (dysesthesia in up to a fifth of 12mg participants in TRIUMPH-4, alongside the usual GI effects) and the cardiovascular-outcomes trial, which has not read out.
Chronic weight management in adults with BMI ≥30 or ≥27 with comorbidity. Primary endpoint: % weight loss vs placebo at 72 weeks.
Glycemic control and weight loss in T2D patients. Primary endpoint: HbA1c reduction and % weight loss.
MACE reduction in high-CV-risk patients. Modeled on SUSTAIN-6 (semaglutide) and SURPASS-CVOT (tirzepatide).
If Phase 3 data confirms Phase 2 efficacy, retatrutide would become the most effective FDA-approved anti-obesity medication by a significant margin. Semaglutide (Wegovy) achieves ~15% weight loss and tirzepatide (Zepbound) achieves ~20–22% — retatrutide's ~24% would represent a meaningful step-change in the drug administration options available to physicians treating obesity.
The cardiovascular outcomes data from Phase 3 will be particularly important. Semaglutide's FLOW trial demonstrated kidney protection benefits that expanded its clinical use significantly. If retatrutide shows similar or superior cardiovascular benefits, it could become the preferred first-line option for patients with obesity and high cardiovascular risk — a very large patient population.
| Drug | Approval Status | Weight Loss | Mechanism |
|---|---|---|---|
| Semaglutide (Wegovy) | FDA Approved (2021) | ~15% | GLP-1 agonist |
| Tirzepatide (Zepbound) | FDA Approved (2023) | ~20–22% | GLP-1 + GIP dual agonist |
| Retatrutide | Not approved — BLA Q1 2027 | 28.3% at 80 wks (Phase 3, 12mg) | GLP-1 + GIP + Glucagon triple agonist |
No. As of September 2026, retatrutide is not FDA approved for any indication and cannot be prescribed. Five Phase 3 TRIUMPH trials have reported positive topline results (TRIUMPH-4 in December 2025; TRIUMPH-1, -2 and -3 and TRANSCEND-T2D-1 in 2026), and Eli Lilly said on 23 July 2026 — and again on its 5 August earnings call — that it plans to submit a Biologics License Application (BLA) in the first quarter of 2027. Approval, if it comes, follows that review.
The earliest realistic window is late 2027, and 2028 is more likely. Lilly has targeted a BLA submission in Q1 2027 (it had earlier guided to a 2026 filing, then pushed it back to complete manufacturing data). A standard FDA review runs about ten to twelve months from acceptance; a priority review runs about six. Counting from a Q1 2027 filing, that puts a decision between roughly late 2027 and mid-2028. No approval date has been set by the FDA.
Retatrutide is at the end of Phase 3. Phase 2 (NCT04881760) completed in 2023 with ~24% mean weight loss at 48 weeks. In Phase 3, TRIUMPH-4 (obesity with knee osteoarthritis) reported −28.7% at 68 weeks in December 2025; TRIUMPH-1 reported −28.3% at 80 weeks on the 12mg dose in May 2026, with 45% of participants losing 30% or more; TRIUMPH-2 and -3 reported −20.8% and −22.6%; TRANSCEND-T2D-1 was positive in type 2 diabetes. Further readouts (sleep apnoea, MASLD, cardiovascular outcomes) are due through 2026–2027.
Lilly has not announced a Breakthrough Therapy designation for retatrutide as of September 2026. The regulatory question that has been reported is a different one: whether retatrutide is filed as a biologic (BLA) or a drug (NDA). Lilly's position, stated by its CEO, is that it is a biologic under the amino-acid-count rule, and the company is preparing a BLA. Priority review, if granted, would shorten the review to about six months.
Retatrutide is being developed for chronic weight management (obesity) and type 2 diabetes as primary indications, consistent with the GLP-class precedent set by semaglutide and tirzepatide. Additional indications under investigation include cardiovascular outcomes (heart disease risk reduction), non-alcoholic fatty liver disease (NAFLD/NASH), and potentially chronic kidney disease. The obesity indication is expected to be the first approved.
Research-grade retatrutide is available from verified suppliers like Purgo Labs for research purposes only. It is not available as a prescription medication in the US prior to FDA approval. Purgo Labs provides research-grade retatrutide with third-party COAs confirming ≥99% purity. All compounds are sold strictly for research purposes.
On the Phase 3 numbers now public, retatrutide's −28.3% at 80 weeks (TRIUMPH-1, 12mg) sits above semaglutide (Wegovy, ~15%) and tirzepatide (Zepbound, ~20–22%) in their pivotal trials. Cross-trial comparisons are imperfect — different populations, durations and estimands — but the gap is large. What is still open is the tolerability profile at the top dose (dysesthesia was reported in about a fifth of 12mg participants in TRIUMPH-4) and the cardiovascular-outcomes data, which has not read out.
While awaiting FDA approval, research-grade retatrutide is available from Purgo Labs with third-party COAs confirming ≥99% purity. All compounds are sold for research purposes only. Code HEALTH is 20% off every order at Purgo Labs (verified recurring).
Shop Purgo LabsUse code HEALTH for 20% off · Research use only