Status checked September 28, 2026: Retatrutide is still investigational and is not available as an FDA-approved prescription. Lilly has now reported five positive Phase 3 studies and says it plans to submit a Biologics License Application (BLA) in Q1 2027. A planned submission is not an approval or launch date.
Retatrutide is one of the most talked-about weight-loss drugs that is not on the market yet. People hear about it online and assume it is another version of Ozempic or Mounjaro. It is not. Retatrutide is a different drug that remains investigational, even after five positive Phase 3 studies.
What retatrutide is
Retatrutide is a next-generation drug being studied for obesity and metabolic health. It is made by Eli Lilly. It works on three pathways:
- GLP-1 — signals fullness, slows digestion
- GIP — works with GLP-1 to boost the effect
- glucagon — increases energy expenditure (burns more calories)
That is why people call it a triple agonist. It is the first drug in this category to target all three receptors at once.
Does retatrutide have a brand name?
No approved retail brand name at this time. That is one of the easiest ways to tell retatrutide apart from semaglutide and tirzepatide.
Semaglutide brand names
- Ozempic
- Wegovy
- Rybelsus
Tirzepatide brand names
- Mounjaro
- Zepbound
Retatrutide brand names
- none approved yet
TRIUMPH-1 results: the general obesity Phase 3 trial
On May 21, 2026, Lilly announced top-line results from TRIUMPH-1, the Phase 3 trial for general obesity. Full data, plus new nested-substudy results, were presented at the ADA 2026 Scientific Sessions (June 5-8, New Orleans). The trial tested retatrutide in a broad obesity population without diabetes.
TRIUMPH-1 primary results at 80 weeks
The trial ran for 80 weeks in adults with obesity who did not have diabetes.
| Retatrutide 4 mg | Retatrutide 9 mg | Retatrutide 12 mg | Placebo | |
|---|---|---|---|---|
| Weight loss (efficacy estimand) | −19.0% (47.2 lbs) | −25.9% (64.4 lbs) | −28.3% (70.3 lbs) | −2.2% (5.5 lbs) |
| Weight loss (treatment-regimen estimand) | −17.6% | −23.7% | −25.0% | −3.9% |
What those terms mean:
- Efficacy estimand estimates the effect if all randomized participants remained on the assigned study treatment, allowing dose interruptions or changes, and did not begin prohibited weight-management treatments.
- Treatment-regimen estimand estimates the average effect regardless of whether participants adhered to the assigned treatment or began prohibited weight-management treatments.
The larger efficacy-estimand values and the treatment-regimen values answer different questions. They should not be mixed or reported without their labels.
Key secondary endpoints at 80 weeks
| Retatrutide 4 mg | Retatrutide 9 mg | Retatrutide 12 mg | Placebo | |
|---|---|---|---|---|
| Reached ≥25% weight loss | 27.8% | 52.9% | 62.5% | 2.2% |
| Reached ≥30% weight loss | 15.3% | 37.9% | 45.3% | 0.5% |
| Reached ≥35% weight loss | 5.9% | 20.8% | 27.2% | 0.3% |
| Waist circumference reduction | −6.4 in | −8.6 in | −9.5 in | −1.4 in |
The 12 mg dose moved 65.3% of participants below a BMI of 30 — including 37.5% of those who started with class 3 obesity (BMI ≥40).
Extension to 104 weeks in a selected 532-person cohort
The pre-specified extension selected 532 participants with baseline BMI ≥35 who completed week 80 on study drug without discontinuation or permanent dose reduction. Participants then continued for 24 weeks with blinded escalation to a maximum tolerated dose (MTD) of 9 mg or 12 mg.
| 4 mg to MTD | 9 mg to MTD | 12 mg to MTD | Placebo to retatrutide MTD | |
|---|---|---|---|---|
| Weight loss at 104 weeks | −27.9% (73.3 lbs) | −29.5% (80.7 lbs) | −30.3% (85.0 lbs) | −19.2% (49.9 lbs) |
Within this selected 532-person extension cohort, participants originally assigned to 12 mg and then escalated as tolerated to MTD averaged 30.3% weight loss at week 104. Separately, at the main 80-week endpoint, 45.3% of participants assigned to 12 mg reached at least 30% weight loss.
Cardiometabolic improvements
TRIUMPH-1 also showed improvements in cardiovascular risk factors:
- Reductions in non-HDL cholesterol
- Reductions in triglycerides
- Reductions in systolic blood pressure
- Reductions in hsCRP (a marker of inflammation)
TRIUMPH-1 also reported improvements in several measured cardiovascular risk factors. These findings do not establish that retatrutide prevents cardiovascular events.
Safety and tolerability in TRIUMPH-1
Discontinuation due to adverse events by dose:
| Retatrutide 4 mg | Retatrutide 9 mg | Retatrutide 12 mg | Placebo | |
|---|---|---|---|---|
| Discontinued due to side effects | 4.1% | 6.9% | 11.3% | 4.9% |
Fewer people stopped treatment for adverse events at 4 mg than at 9 mg or 12 mg. At 12 mg, 11.3% stopped because of adverse events, compared with 4.9% with placebo.
New at ADA 2026: sleep apnea and knee osteoarthritis substudies
Nested substudies within TRIUMPH-1, presented at the ADA 2026 Scientific Sessions and reported in Lilly's June 6 primary results release, looked at participants who also had obstructive sleep apnea or knee osteoarthritis:
- Obstructive sleep apnea: a 60.6% reduction in the apnea-hypopnea index (AHI), down from a severe-OSA baseline of 58.6 events per hour, at the 12 mg dose
- Knee osteoarthritis: a 73.1% reduction in knee pain (a 4.3-point improvement) at the 12 mg dose
These are in addition to — not a replacement for — the dedicated TRIUMPH-4 trial (below), which specifically enrolled people with obesity and knee osteoarthritis.
Retatrutide vs Zepbound vs Wegovy vs CagriSema: direct comparison table
The table below compares Phase 3 obesity trial results across these four drugs. Important caveat: these are cross-trial comparisons, not head-to-head studies. Each trial enrolled different populations, used different durations, and measured endpoints differently. Direct numerical comparison should be interpreted with caution.
| Retatrutide (TRIUMPH-1) | Zepbound (SURMOUNT-1) | Wegovy (STEP 1) | CagriSema (REDEFINE 1) | |
|---|---|---|---|---|
| Mechanism | Triple agonist (GLP-1 + GIP + glucagon) | Dual agonist (GLP-1 + GIP) | GLP-1 only | Dual (GLP-1 + amylin) |
| Trial duration | 80 weeks (extension to 104) | 72 weeks | 68 weeks | 68 weeks |
| Highest dose weight loss | 28.3% (70.3 lbs) | ~22.5% | ~15% | 20.4% |
| Extension/longer-term | 30.3% at 104 weeks in a selected 532-person cohort with baseline BMI ≥35 that completed week 80 on study drug without discontinuation or permanent dose reduction | — | — | — |
| % reaching ≥30% weight loss | 45.3% (12 mg) | ~30% (15 mg) | ~12% (2.4 mg) | Not reported |
| FDA status | Investigational; BLA planned Q1 2027 | Approved (2023) | Approved (2021) | Under FDA review (NDA filed Dec 2025) |
| Current availability | Not available — investigational | Available by prescription | Available by prescription | Not available — under review |
Key limitations of this comparison:
- Different trial populations (TRIUMPH-1 excluded diabetes; SURMOUNT-1 and STEP 1 had different inclusion criteria)
- Different trial durations (68–80 weeks for primary endpoints)
- Different statistical methods and estimand frameworks
- SURMOUNT-1 and STEP 1 used earlier estimand approaches; TRIUMPH-1 used a treatment-policy–style estimand consistent with more recent FDA guidance
- CagriSema's REDEFINE 1 used a different comparator design
These numbers give a general sense of relative efficacy, but no drug can be definitively ranked against another without a head-to-head trial.
The weekly GLP-1 email
Plain-English answers on side effects, eating, cost and the newest medications. Free, one email a week.
Other Phase 3 trial results
Lilly's July 23 update added TRIUMPH-2 and TRIUMPH-3, bringing the company's reported total to five positive Phase 3 studies. The figures below are efficacy-estimand results from Lilly's top-line release; detailed results had not yet been published in a peer-reviewed journal when the release appeared.
TRIUMPH-2 (obesity or overweight with type 2 diabetes)
At 80 weeks, average weight loss in clinical trials was 12.7%, 19.1%, and 20.8% with 4 mg, 9 mg, and 12 mg, versus 4.0% with placebo. Average A1C fell 1.4, 1.6, and 1.5 percentage points across those doses, versus 0.2 points with placebo.
TRIUMPH-3 (severe obesity and established cardiovascular disease)
At 80 weeks, average weight loss in clinical trials was 21.6% with 9 mg and 22.6% with 12 mg, versus 3.2% with placebo. The trial observed fewer major cardiovascular events than expected, and its confidence intervals did not establish a cardiovascular benefit. Lilly reported a MACE-5 hazard ratio of 0.82 (95% CI 0.55 to 1.22) and a MACE-3 hazard ratio of 1.12 (95% CI 0.64 to 1.96) for pooled retatrutide doses versus placebo.
TRIUMPH-4 (obesity with knee osteoarthritis)
Lilly reported top-line results in December 2025 from adults with obesity or overweight and knee osteoarthritis, without diabetes.
| Weight loss at 68 weeks | Retatrutide 9 mg | Retatrutide 12 mg | Placebo |
|---|---|---|---|
| Efficacy estimand | −26.4% | −28.7% | −2.1% |
| Treatment-regimen estimand | −20.0% | −23.7% | −4.6% |
TRANSCEND-T2D-1 (type 2 diabetes)
Top-line results were reported in March 2026; final data were presented at ADA 2026 (June 5-8, New Orleans) and simultaneously published in The Lancet. The trial included 537 adults with type 2 diabetes (baseline A1C 7.9%, baseline BMI 35.8, mean 2.5-year T2D duration) over 40 weeks.
| Endpoint and estimand | Retatrutide 4 mg | Retatrutide 9 mg | Retatrutide 12 mg | Placebo |
|---|---|---|---|---|
| Weight loss, efficacy estimand | −11.5% | −15.5% | −16.8% | −2.5% |
| Weight loss, treatment-regimen estimand | −11.5% | −13.9% | −15.3% | −2.6% |
| A1C change, efficacy estimand | −1.7 points | −2.0 points | −1.9 points | −0.8 points |
| A1C change, treatment-regimen estimand | −1.7 points | −1.9 points | −1.9 points | −0.8 points |
At the 12 mg dose, weight loss reached 16.8% (36.6 lbs) by week 40 without plateauing — meaning people were still losing weight when the trial measurement ended. Up to 90% of participants reached an A1C below 7.0%, and 46% reached a normal A1C (below 5.7%).
What does the glucagon part mean?
This is where articles often get too technical. The simple version is:
Retatrutide is being studied as a more aggressive metabolic drug. The glucagon receptor increases energy expenditure — meaning your body burns more calories even at rest. That is on top of the fullness and appetite signals from GLP-1 and GIP.
That does not automatically mean better for everyone. It means the drug is trying to affect the body in a broader way than semaglutide or tirzepatide alone.
Side effects and safety
The most common side effects in the Phase 3 trials were the same ones you see with other GLP-1 drugs:
- nausea
- diarrhea
- constipation
- vomiting
- decreased appetite
These were mostly mild to moderate and happened most during dose increases.
A new side effect worth knowing about
The trials also reported dysesthesia, a tingling, burning, or numb sensation. In TRIUMPH-1, Lilly reported:
- 5.1% at 4 mg
- 12.3% at 9 mg
- 12.5% at 12 mg
- 0.9% with placebo
Lilly said these events were generally mild to moderate, most resolved during treatment, and most participants continued taking retatrutide. Dysesthesia was also reported in the other Phase 3 studies, at different rates.
Discontinuation rates across trials
| Trial | Lowest dose | Highest dose | Placebo |
|---|---|---|---|
| TRIUMPH-1 (general obesity) | 4.1% (4 mg) | 11.3% (12 mg) | 4.9% |
| TRIUMPH-4 (knee OA) | 12.2% (9 mg) | 18.2% (12 mg) | 4.0% |
| TRANSCEND-T2D-1 (diabetes) | 2.2% (4 mg) | 5.1% (12 mg) | 0% |
In TRIUMPH-4, some discontinuations were because participants felt they had lost too much weight. In TRANSCEND-T2D-1, discontinuation was much lower overall.
When could retatrutide become available?
Retatrutide is not approved or available by prescription. Lilly has announced a filing plan, not an approval date.
Lilly has reported five positive Phase 3 studies. The company says those results provide the clinical data package to support global submissions for potential obesity, knee osteoarthritis pain, and obstructive sleep apnea indications. It is still completing the chemistry, manufacturing, and controls package needed for a U.S. BLA.
Here is what the timeline looks like:
- December 2025: TRIUMPH-4 top-line results (obesity + knee osteoarthritis) — positive
- March 2026: TRANSCEND-T2D-1 top-line results (type 2 diabetes) — positive
- May 21, 2026: TRIUMPH-1 top-line results (general obesity) — positive
- June 5-8, 2026: Full TRIUMPH-1 and TRANSCEND-T2D-1 data presented at the ADA 2026 Scientific Sessions in New Orleans, with TRANSCEND-T2D-1 simultaneously published in The Lancet
- July 23, 2026: Lilly reported positive TRIUMPH-2 and TRIUMPH-3 top-line results, bringing the total to five positive Phase 3 studies
- Q1 2027: Lilly plans to submit a BLA to FDA after completing its chemistry, manufacturing, and controls package
Lilly has not announced an approval or launch date. FDA can approve, delay, or reject an application, so the Q1 2027 filing plan should not be converted into a predicted pharmacy date.
What to watch next in 2026
A few things that could change the picture:
- Detailed TRIUMPH-2 and TRIUMPH-3 data — Lilly said full results would be presented at future medical meetings and published in peer-reviewed journals.
- The planned BLA — Lilly's current target is Q1 2027. The filing itself, if accepted, will provide a firmer regulatory milestone but not a guaranteed decision date.
Why this article needs caution
Retatrutide content gets weird fast online. You will see:
- hype
- rumor
- people acting like approval already happened
- people talking about it like it is the obvious winner before the dust has settled
The Phase 3 results are genuinely strong. But the smart view is still:
- yes, it is interesting — more than ever
- yes, the trial numbers are real
- no, that does not make every dramatic claim true
- no, you cannot get it at a pharmacy yet
What questions people usually have
Most readers are trying to answer one of these:
- What is retatrutide?
- Is retatrutide better than semaglutide?
- Is retatrutide better than tirzepatide?
- Does retatrutide have a brand name?
- Can you actually get retatrutide yet?
- When will retatrutide be approved?
The clean answer right now: Retatrutide is a triple-agonist investigational drug with five positive Phase 3 studies reported by Lilly. It does not have an approved brand name, and it should not be discussed like a routine retail GLP-1 medication. Lilly plans a Q1 2027 BLA submission, but there is no announced approval or launch date.
Bottom line
Lilly has reported five positive Phase 3 studies, including average weight loss in clinical trials of up to 28.3% in TRIUMPH-1 and 28.7% in TRIUMPH-4 under the efficacy estimand. Retatrutide remains investigational as of September 28, 2026. Lilly plans a Q1 2027 BLA submission, but the drug has no approved brand name, FDA approval, or announced launch date.
If you want to compare it with what is already available, read next:
- Semaglutide Guide: Ozempic, Wegovy, and Rybelsus Explained
- Tirzepatide Guide: Mounjaro and Zepbound Explained
- GLP-1 Medications Explained
- Best GLP-1 for Weight Loss 2026
- Zepbound vs Retatrutide
- Ozempic vs Retatrutide
- Mounjaro vs Retatrutide
- Foundayo (Orforglipron): GLP-1 Pill With No Food Rules
- CagriSema Weight Loss Guide
Disclaimer: This content is for informational purposes only and does not constitute medical advice. Retatrutide is an investigational drug that is not yet approved by the FDA. Talk to your healthcare provider about treatment options that are right for you.
Frequently asked questions
Is retatrutide FDA-approved?
No. Retatrutide remains investigational as of September 28, 2026. Lilly has reported five positive Phase 3 studies and plans to submit a Biologics License Application in the first quarter of 2027, but a planned filing is not FDA approval.
When might retatrutide be available?
Lilly says it plans to submit a Biologics License Application for retatrutide in Q1 2027. The company has not announced an approval or launch date, and FDA review can result in approval, delay, or rejection.
What did the May 2026 TRIUMPH-1 trial show?
TRIUMPH-1 is the general obesity Phase 3 trial. Top-line results reported May 21, 2026 showed up to 28.3% average weight loss at the highest dose (12 mg) over 80 weeks. In a selected 532-person extension cohort with baseline BMI ≥35 that completed week 80 on study drug without discontinuation or permanent dose reduction, participants originally assigned to 12 mg averaged 30.3% weight loss at week 104 after escalation to a maximum tolerated dose. Full data, including new knee-osteoarthritis and sleep-apnea substudy results, were presented at the ADA 2026 Scientific Sessions (June 5-8, New Orleans). Retatrutide remains investigational and is not FDA-approved.
What new retatrutide data came out of ADA 2026 in June?
At the ADA 2026 Scientific Sessions (June 5-8, New Orleans), Eli Lilly presented full TRIUMPH-1 data plus nested substudy results: a 60.6% reduction in the apnea-hypopnea index and a 73.1% reduction in knee pain at the 12 mg dose in the respective substudy populations. Lilly also presented and simultaneously published full TRANSCEND-T2D-1 (type 2 diabetes) results in The Lancet, confirming A1C reductions of up to 2.0% and weight loss up to 16.8% (36.6 lbs) at the 12 mg dose over 40 weeks. Retatrutide remains investigational, and Lilly plans a BLA submission in Q1 2027.
Does retatrutide beat Zepbound or Wegovy?
TRIUMPH-1 showed higher average weight loss than what Zepbound (~22.5%) or Wegovy (~15%) achieved in their own Phase 3 trials. But these are cross-trial comparisons — not head-to-head studies — with different populations, durations, and endpoints. Retatrutide is also not approved yet, so no one can take it right now. Talk to your doctor about what is available today.
What are the side effects of retatrutide?
The most common side effects in trials include nausea, diarrhea, vomiting, and constipation. Dysesthesia, described as tingling, burning, or numbness, was also reported. In TRIUMPH-1, adverse-event discontinuation rates were 4.1%, 6.9%, and 11.3% for the 4 mg, 9 mg, and 12 mg groups, versus 4.9% with placebo.
What is the dysesthesia side effect with retatrutide?
Dysesthesia is a tingling, burning, or numb sensation reported in Phase 3 trials. In TRIUMPH-1 it occurred in 5.1%, 12.3%, and 12.5% of participants assigned to 4 mg, 9 mg, and 12 mg, versus 0.9% with placebo. Lilly said these events were generally mild to moderate and most resolved during treatment.
