Regulatory tracker
Retatrutide: FDA status and trial tracker
Last updated: · Reviewed at each phase 3 readout
Written by Frank Muscarello
Citations independently verified against PubMed, ClinicalTrials.gov, and FDA sources on . Independent clinical review pending.
Frank is not a clinician; this page reports regulatory and trial status and does not offer clinical guidance.
Retatrutide is not an FDA-approved drug. It is an investigational once-weekly triple hormone receptor agonist (GIP, GLP-1 and glucagon) developed by Eli Lilly as LY3437943. Four phase 3 trials have reported topline results; seven more readouts are expected through 2026. Eli Lilly has not filed for approval, and no lawful supply exists outside a registered clinical trial.
An investigational drug. Not approved by the FDA for any indication and not lawfully available outside a registered clinical trial.
Elevate Chicago does not prescribe, compound, or sell this compound. This page exists because it is one of the most-asked-about molecules in metabolic medicine and most of what is published about it is wrong in a specific, checkable way. We record what the trials found, including the parts that are less flattering.
Why the numbers you have seen are probably the higher ones
The headline figure circulating for retatrutide's first phase 3 readout is 28.7% body weight loss. That number is real. It is also the efficacy estimand — the analysis restricted to participants who stayed on treatment.
Lilly reported the same trial under a second analysis, the treatment-regimen estimand, which includes everyone randomised regardless of whether they discontinued. Under that analysis the same dose produced 23.7%. Both are legitimate and both were published. Regulators weight the second more heavily, because it reflects what happens to everyone who starts the drug rather than everyone who finishes it.
Every trial on this page shows both figures where both were reported. That is the entire reason this page exists.
Phase 3 readouts to date
TRIUMPH-4 — obesity or overweight with knee osteoarthritis
68 weeks, 445 participants randomised 1:1:1 to retatrutide 9 mg, 12 mg or placebo. Mean baseline weight 112.7 kg, mean baseline BMI 40.4 kg/m²; 84% entered with BMI ≥35. Reported December 11, 2025. Co-primary endpoints were percent change in body weight and WOMAC pain subscale score at week 68; both were met.
| Endpoint | Efficacy estimand | Treatment-regimen estimand |
|---|---|---|
| Weight, 12 mg | −28.7% | −23.7% |
| Weight, 9 mg | −26.4% | −20.0% |
| Weight, placebo | −2.1% | −4.6% |
| WOMAC pain, 12 mg | −4.5 pts (−75.8%) | −3.7 pts (−62.6%) |
| WOMAC pain, 9 mg | — | −4.0 pts (−67.2%) |
| WOMAC pain, placebo | −2.4 pts (−40.3%) | −2.1 pts (−35.1%) |
Both estimands as reported by Eli Lilly. Detailed results have not yet been published in a peer-reviewed journal.
In a post-hoc analysis, roughly one in eight retatrutide-treated participants reported being completely free of knee pain at week 68, against just over 4% on placebo.
Tolerability — the part usually left out
| 9 mg | 12 mg | Placebo | |
|---|---|---|---|
| Discontinued for adverse events | 12.2% | 18.2% | 4% |
| Nausea | 38.1% | 43.2% | 10.7% |
| Diarrhoea | 34.7% | 33.1% | ~13% |
TRIUMPH-4 adverse events, as reported by Eli Lilly.
Roughly one in five participants on the highest dose stopped the drug for an adverse event. Lilly noted that discontinuation rates correlated with baseline BMI and that some discontinuations were driven by perceived excessive weight loss.
Other phase 3 readouts
| Trial | Population | Weight, 12 mg | Reported |
|---|---|---|---|
| TRIUMPH-1 | Obesity or overweight (master trial, 2,339 randomised) | −28.3% at 80 wk −30.3% at 104 wk* | May 21, 2026 |
| TRIUMPH-2 | Obesity with type 2 diabetes | −20.8% | Jul 23, 2026 |
| TRIUMPH-3 | Obesity with established cardiovascular disease | −22.6% at 80 wk | Jul 23, 2026 |
| TRANSCEND-T2D-1 | Type 2 diabetes | — | Mar 2026 |
*The 104-week figure comes from a pre-specified blinded extension in 532 participants who had baseline BMI ≥35 and tolerated their assigned dose — a selected subgroup, not the full randomised cohort.
A number worth retiring. A 24.2% weight-loss figure circulated for years attributed to phase 3 results. It was never a phase 3 result — it came from the 2023 phase 2 obesity study at 48 weeks. This is how a number drifts loose from its trial and becomes folklore, and it is worth knowing when you read anything about this compound.
Cardiovascular outcomes: not yet answered
TRIUMPH-3 reported in-study cardiovascular event rates with a hazard ratio of 0.82 (95% CI 0.55–1.22) for a five-component MACE composite and 1.12 (95% CI 0.64–1.96) for three-component MACE. Both confidence intervals cross 1.0.
That trial was not designed or powered to measure cardiovascular outcomes. Read those hazard ratios as reassurance that nothing alarming appeared — not as evidence of cardiovascular benefit. The event-driven TRIUMPH-Outcomes trial (NCT06383390) is the study designed to answer that question, and it has not reported.
Why this matters for the word "disease-modifying." Disease modification is a claim about outcomes — fewer events, less progression, longer life. Establishing it requires outcome trials. For retatrutide those trials are ongoing and none has read out. Weight loss, liver fat reduction and pain scores are all meaningful findings, and none of them is an outcome.
Liver fat: the strongest signal in the dataset
A substudy of the phase 2 obesity trial (NCT04881760) enrolled 98 participants with metabolic dysfunction-associated steatotic liver disease and at least 10% liver fat by MRI, randomised to retatrutide 1, 4, 8 or 12 mg or placebo for 48 weeks. Published in Nature Medicine, 2024.
| Dose | Liver fat change | Reached normal liver fat (<5%) |
|---|---|---|
| 1 mg | −42.9% | 27% |
| 4 mg | −57.0% | 52% |
| 8 mg | −81.4% | 79% |
| 12 mg | −82.4% | 86% |
| Placebo | +0.3% | 0% |
Mean relative change in liver fat at 24 weeks. All doses p<0.001 versus placebo.
These are the largest hepatic fat reductions reported for any agent in this class, and the 86% figure is the published, abstract-level number at the primary timepoint.
On the 93% figure. A higher normalisation rate is sometimes quoted for this trial. It does not appear in the published abstract, and week-48 MRI sample sizes were in the single digits per arm. Use 86% at 24 weeks — it rests on the full randomised cohort at the primary endpoint, and it is remarkable enough without inflation.
What this data does not establish
These limits are not caveats appended for form. They are the difference between what the trials showed and what the compound is being sold as online.
The liver endpoint was imaging, not histology
Liver fat by MRI is a legitimate early marker. It is not fibrosis regression and it is not a clinical outcome. Fibrosis stage is what predicts mortality in steatotic liver disease, and this substudy does not speak to it. The dedicated phase 3 MASLD programme has not reported.
MASLD is defined by the absence of significant alcohol use
The diagnostic criteria exclude alcohol-associated liver disease by construction, and the mechanism under study was insulin resistance driving hepatic fat accumulation. There is no data on retatrutide in alcohol-related liver injury, and the two conditions do not share a driver.
No data in cirrhosis
Trials in this class routinely exclude significant hepatic impairment. There is no efficacy or safety data in compensated or decompensated cirrhosis. This matters because lean mass predicts mortality in cirrhosis independent of MELD, and weight loss of 20–30% raises questions about muscle that these trials were not designed to answer.
Populations were severely obese
TRIUMPH-4 had a mean baseline BMI of 40.4, with 84% at BMI ≥35. The MASLD substudy required ≥10% liver fat to enter. Results in a severely obese, high-liver-fat population do not transfer automatically to someone outside it.
Preprints are not peer-reviewed evidence
Emerging neuroprotection and cognition work on this compound has appeared on preprint servers. Preprints are not peer-reviewed or editorially screened. They belong in a different tier from registrational phase 3 data, and presenting them together flattens a distinction that matters.
What would have to happen for this to become available
| Step | Status |
|---|---|
| Phase 3 programme completes | Four trials reported; seven further readouts expected through 2026, including TRIUMPH-5 (head-to-head against tirzepatide), TRIUMPH-6 (weight maintenance) and the MASLD readouts |
| FDA submission | Not yet filed. Publicly estimated for Q4 2026 or Q1 2027 — an estimate, not a commitment |
| FDA review | Has not begun |
| Approval | No approval exists in any jurisdiction |
| TRIUMPH-Outcomes (cardiovascular) | Ongoing, event-driven, not reported |
Until an approval issues, there is no lawful pathway to obtain retatrutide outside a registered clinical trial. Material sold online under this name has no enforceable standard for identity, potency, sterility or endotoxin content, and no clinical evaluation changes that.
Frequently asked questions.
- Is retatrutide FDA-approved?
- No. It is investigational. Eli Lilly has not filed a marketing application, and no regulator anywhere has approved it. Positive phase 3 results are not approval — they are the evidence a company submits when it applies.
- How is it different from semaglutide and tirzepatide?
- Semaglutide activates the GLP-1 receptor. Tirzepatide activates GIP and GLP-1. Retatrutide adds a third: the glucagon receptor. Glucagon receptor agonism increases energy expenditure and acts directly on hepatic lipid metabolism, which is the mechanistic argument for the liver fat findings above. Both semaglutide and tirzepatide are FDA-approved and lawfully prescribable. Retatrutide is neither.
- When might it be approved?
- Submission has been publicly estimated for Q4 2026 or Q1 2027. FDA review then typically runs months, not weeks. Any date given today is an estimate about a filing that has not happened, and we will update this page when the docket moves rather than speculating.
- Can I get it from a compounding pharmacy?
- No. Compounding under section 503A requires a bulk drug substance that is either an FDA-approved drug component, the subject of a USP monograph, or on the 503A bulks list. Retatrutide is none of these. A licensed pharmacy cannot lawfully compound it, and one offering to is not operating within that pathway.
- What about the material sold online as "research use only"?
- Research-use-only is not a category that permits human use. It is an exemption from the manufacturing and approval standards that would otherwise apply, and it holds only while the product genuinely is not intended for human consumption. RUO material carries no enforceable identity, potency, sterility or endotoxin standard. We do not sell research compounds to patients, and we do not refer patients elsewhere to buy them.
- Does Elevate Chicago prescribe retatrutide?
- No, and we will not until it is approved and lawfully available through a licensed pharmacy. Where an FDA-approved incretin therapy is clinically appropriate, we prescribe the approved product by name and a licensed pharmacy dispenses it. Where a therapy is not available, we say so and tell you what would have to change.
We will tell you the day this changes
This page is updated whenever a phase 3 trial reports, a filing is made, or the FDA acts. If you want to know when retatrutide becomes lawfully available — or when it does not — write to us and we will note it.
This is a notification request, not a purchase path. Asking to be notified does not create a clinical relationship and nothing is sold from this page.
Ask to be notifiedSources
- 1.TRIUMPH-4 topline results, December 11, 2025— Eli Lilly
- 2.TRIUMPH-1 topline results, May 21, 2026— Eli Lilly
- 3.Sanyal et al. — Triple hormone receptor agonist retatrutide for MASLD: a randomized phase 2a trial (NCT04881760)— Nature Medicine, 2024
- 4.Rationale and design of the TRIUMPH registrational trials, 2026;28(1):83–93— Diabetes, Obesity and Metabolism
- 5.TRIUMPH-4 estimand and discontinuation detail— Healio
- 6.TRIUMPH-4 treatment-regimen estimand results— Rheumatology Live
Related
- 503A peptide compounding tracker — the July 2026 PCAC votes and what listing would and would not mean
- Metabolic and weight therapy — the approved incretin therapies we do prescribe
- Peptide therapy · Hormone therapy
About this page
Citations independently verified against PubMed, ClinicalTrials.gov, and FDA sources on . Independent clinical review pending. Educational content only — not medical advice, not a diagnosis, and not an offer to sell any prescription product.
This page is educational and is not medical advice. It does not recommend, offer, or facilitate access to any investigational compound. Speak with a licensed clinician before beginning any therapy.