Retatrutide FDA Approval Tracker: Every Trial, Every Date

Where Retatrutide Stands on the Road to Approval

This retatrutide approval tracker records every Phase 3 readout, the regulatory filing plan, and the realistic approval window — updated as Lilly reports. As of late September 2026, three of the four pivotal obesity trials have reported, the BLA filing is planned for Q1 2027, and the earliest plausible FDA decision is the second half of 2027.

Retatrutide (LY3437943) is Eli Lilly’s investigational triple agonist — it activates GIP, GLP-1, and glucagon receptors. It is not approved anywhere. Everything below is trial data and company guidance, not label information.

Trial Results to Date

Trial	Population	Reported	12 mg result	N	Notes
Phase 2 (NEJM)	Obesity, no diabetes	Jun 2023	−24.2% at 48 wk	338	Jastreboff et al.; the only peer-reviewed publication
TRIUMPH-4	Obesity + knee osteoarthritis	Dec 2025	−28.7% at 68 wk	445	First Phase 3 readout; dysesthesia 20.9% at 12 mg
TRANSCEND-T2D-1	Type 2 diabetes	Mar 2026	−16.8% at 40 wk	—	Diabetes-focused; A1C primary
TRIUMPH-1	Obesity/overweight, no diabetes	May 21, 2026	−28.3% at 80 wk; −30.3% at 104 wk (BMI ≥35 extension)	2,339	Pivotal; 45.3% lost ≥30%; placebo −2.2%
TRIUMPH-2	Obesity + type 2 diabetes	Jul 23, 2026	−20.8% at 80 wk; A1C −1.6%	—	Detailed data at EASD Sep 30
TRIUMPH-3	Severe obesity + cardiovascular disease	Jul 23, 2026	−22.6% at 80 wk	—	Highest-risk population
TRIUMPH-5	Head-to-head vs tirzepatide	2027+	—	—	Active, not recruiting (NCT06662383)
TRIUMPH-Outcomes	Cardiovascular/kidney outcomes	2028+	—	~10,000	CVOT; multi-year (NCT06383390)

Sources: Eli Lilly press releases (Dec 2025, May 21 2026, Jul 23 2026, Sep 15 2026); Jastreboff AM et al., N Engl J Med 2023;389:514–526; ClinicalTrials.gov. Figures are efficacy-estimand topline results unless noted.

The Regulatory Timeline

Lilly confirmed on July 23, 2026 that it plans to submit a Biologics License Application to FDA in the first quarter of 2027. This is a BLA rather than an NDA because retatrutide is regulated as a biologic — a detail that corrected earlier third-party estimates pointing to a Q4 2026 NDA (Lilly, July 23, 2026).

From filing, FDA has 60 days to accept the application and set a PDUFA date. Standard review is 10–12 months; priority review is approximately 6 months. Whether priority review is granted is not yet known. Wegovy (2021) and Zepbound (2023) both received it, but the argument for priority is weaker now that multiple effective obesity drugs are on the market — including Lilly’s own Foundayo (orforglipron), approved earlier in 2026.

Milestone	Timing	Status
TRIUMPH-1 pivotal readout	May 21, 2026	✅ Done
TRIUMPH-2 and -3 readouts	Jul 23, 2026	✅ Done
EASD symposium (TRIUMPH-2 detail)	Sep 30, 2026	Scheduled
Peer-reviewed publication of TRIUMPH-1	Late 2026 (expected)	Pending
BLA submission	Q1 2027	Planned
FDA filing acceptance + PDUFA date	~Q2 2027	—
FDA decision — priority review	~Q3–Q4 2027	—
FDA decision — standard review	~Q1–Q2 2028	—
Commercial launch	1–3 months after approval	—

What TRIUMPH-1 Established

TRIUMPH-1 is the trial the BLA will anchor on — the broad obesity population without diabetes that retatrutide will be prescribed to after approval. Its 2,339 participants had an average baseline weight of 112.7 kg and BMI of 40. At 80 weeks, the 12 mg arm lost 28.3% (70.3 lbs), the 9 mg arm 25.9%, and the 4 mg arm 19.0%, against 2.2% on placebo. All three doses met the primary and key secondary endpoints (Lilly, May 21, 2026).

The 30.3% figure that circulates comes from a pre-specified blinded extension: participants with baseline BMI of 35 or higher who completed 80 weeks and tolerated their dose continued to 104 weeks, and the 12 mg group reached an average 30.3% (85.0 lbs). That is a subgroup, not the headline result, and it suggests weight loss had not plateaued at 80 weeks in the heaviest participants.

Escalation in the trial was 2 → 4 → 6 → 9 → 12 mg in four-week steps. The 4 mg dose is notable because it required only one escalation step from the starting dose and still produced 19% loss with a lower discontinuation rate — Lilly has flagged it as a potential maintenance dose.

The Safety Signal to Watch

Dysesthesia — abnormal skin sensations including tingling, burning, or heightened sensitivity — is the side effect that distinguishes retatrutide from earlier GLP-1 drugs. In TRIUMPH-4 it occurred in 8.8% of the 9 mg arm and 20.9% of the 12 mg arm against 0.7% on placebo. It is thought to relate to the glucagon-receptor component and is generally described as mild to moderate and transient, but it is dose-dependent and will be part of FDA’s review.

Adverse-event discontinuation in TRIUMPH-1 ran 4.1% (4 mg), 6.9% (9 mg), and 11.3% (12 mg). Gastrointestinal effects — nausea, vomiting, constipation — follow the class pattern and are managed by the four-week escalation schedule. The TRIUMPH-Outcomes cardiovascular trial, expected to read out in 2028 or later, will be required for any cardiovascular label claim but is not a gate for the obesity approval.

What Is Still Unknown

Three things will shape the label and the launch. First, the comorbidity criteria — whether FDA restricts the indication to BMI ≥30 or BMI ≥27 with a weight-related condition, as it did for Wegovy and Zepbound. Second, the head-to-head against tirzepatide in TRIUMPH-5, which will not report before 2027 and will determine whether retatrutide is positioned as a step up from Zepbound or an alternative to it. Third, price — Lilly has not guided, but the $675 list price Novo set for Wegovy and Ozempic from January 2027 and Lilly’s own pricing for Foundayo will frame it.

Nothing published so far suggests a regulatory obstacle to approval. The trial program has met its endpoints across four populations, the safety profile is characterized, and the filing plan is public. The open question is timing — priority or standard review — and that decision sits with FDA after the BLA is accepted (GLP-3 Wiki trial tracker).

Frequently Asked Questions

When will retatrutide be FDA approved?

Lilly plans to file the BLA in Q1 2027. If FDA grants priority review, a decision is plausible in the second half of 2027. Under standard review, the window is the first half of 2028. Commercial availability typically follows approval by one to three months. No date has been confirmed by FDA.

Is retatrutide available anywhere now?

Not as an approved medication. It is investigational and not approved by FDA, EMA, or MHRA. There is no compounded retatrutide — compounding requires an approved reference drug or a listed bulk substance, and retatrutide is neither. Anything sold as retatrutide outside a clinical trial is a research chemical, and FDA’s August 2026 warning letters named it specifically.

How does retatrutide compare to tirzepatide and semaglutide?

By trial results at similar timepoints: retatrutide 28.3% at 80 weeks (TRIUMPH-1), tirzepatide 22.5% at 72 weeks (SURMOUNT-1), semaglutide 14.9% at 68 weeks (STEP 1). These are different trials with different populations, not head-to-head comparisons. The direct comparison against tirzepatide is TRIUMPH-5, which will not report until 2027 or later.

What is the dysesthesia side effect?

Abnormal skin sensations — tingling, burning, or heightened touch sensitivity — reported in 20.9% of participants at the 12 mg dose in TRIUMPH-4 versus 0.7% on placebo. It appears to be dose-dependent and is not seen with GLP-1 or GLP-1/GIP drugs, which points to the glucagon-receptor component. Lilly describes it as generally mild to moderate and transient.

PeptideQuill covers the research peptide industry. This tracker is updated as Lilly reports. Last updated September 24, 2026. This content is informational and does not constitute medical advice.