June 2026 update: Following May 21, 2026 top-line results, Eli Lilly presented full TRIUMPH-1 data at the ADA 2026 Scientific Sessions (June 5-8, New Orleans), including new nested-substudy results on sleep apnea and knee osteoarthritis. Lilly also presented and simultaneously published full TRANSCEND-T2D-1 (type 2 diabetes) Phase 3 results in The Lancet. On the general-obesity trial, people on the highest dose lost up to 28.3% of their body weight over 80 weeks; a subset of participants with BMI ≥35 who continued to 104 weeks reached 30.3% weight loss (85 lbs) — the highest average weight loss reported in any Phase 3 obesity trial to date. But retatrutide is still not FDA-approved and not available at any pharmacy.
Retatrutide is one of the most talked-about weight-loss drugs that is not on the market yet. That matters. People hear about it online, see dramatic claims, and assume it is just another version of Ozempic or Mounjaro. It is not. Retatrutide is a different drug that is still investigational — but it now has three successful Phase 3 trials behind it, and the weight loss numbers are the highest seen in any obesity drug trials to date.
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). This is the trial people have been waiting for, because it tests retatrutide in the broadest obesity population (not limited to people with knee osteoarthritis or 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) | — | — | −25.0% | — |
What those terms mean:
- Efficacy estimand — measures the drug's effect assuming people stay on it (includes data regardless of whether people stopped early, using statistical methods to account for dropouts)
- Treatment-regimen estimand — measures what actually happened to people who took the drug as directed, including those who stopped
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 (BMI ≥35 participants who continued)
| 4 mg to MTD | 9 mg to MTD | 12 mg to MTD | Placebo to 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) |
The 30.3% average weight loss at 104 weeks is the highest average weight loss reported in any Phase 3 obesity trial to date. The 45.3% of 12 mg participants reaching ≥30% weight loss is a level previously associated with bariatric surgery outcomes.
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)
All three Phase 3 trials now show improvements in cardiovascular risk factors like blood pressure, cholesterol, and inflammation markers.
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 at the 4 mg dose than at higher doses — reflecting lower gastrointestinal burden at this dose. At the 12 mg dose, 11.3% stopped due to side effects (primarily gastrointestinal issues). Some discontinuations at higher doses were because participants felt they had lost too much weight.
New at ADA 2026: sleep apnea and knee osteoarthritis substudies
Nested substudies within TRIUMPH-1, presented at the ADA 2026 Scientific Sessions, 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 wks (BMI ≥35) | — | — | — |
| % reaching ≥30% weight loss | 45.3% (12 mg) | ~30% (15 mg) | ~12% (2.4 mg) | Not reported |
| FDA status | Not yet filed; Phase 3 ongoing | Approved (2023) | Approved (2021) | Under FDA review (NDA filed Dec 2025); decision expected Q4 2026 |
| 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.
Other Phase 3 trial results
TRIUMPH-4 (obesity with knee osteoarthritis)
Results reported December 2025. Adults with obesity and knee osteoarthritis.
| Retatrutide 9 mg | Retatrutide 12 mg | Placebo | |
|---|---|---|---|
| Weight loss at 72 weeks | −22.3% | −28.7% | −1.8% |
TRANSCEND-T2D-1 (type 2 diabetes)
Top-line results reported March 2026; final data presented at ADA 2026 (June 5-8, New Orleans) and simultaneously published in The Lancet. 537 adults with type 2 diabetes (baseline A1C 7.9%, baseline BMI 35.8, mean 2.5-year T2D duration) over 40 weeks.
| Retatrutide 4 mg | Retatrutide 9 mg | Retatrutide 12 mg | Placebo | |
|---|---|---|---|---|
| Weight loss | −11.5% | −13.9% | −15.3% | −2.6% |
| A1C reduction (from 7.9% baseline) | −1.7% | −2.0% | −1.9% | −0.8% |
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, usually mild. This showed up in all three Phase 3 trials:
- TRIUMPH-1: 20.9% at 12 mg (vs 4.9% placebo discontinuation overall)
- TRIUMPH-4: 8.8% (9 mg) and 20.9% (12 mg) vs 0.7% with placebo
- TRANSCEND-T2D-1: 2.3% to 4.5% vs 0% with placebo
Most cases were mild and did not cause people to stop the drug. But this is a new signal that researchers are watching.
Discontinuation rates across trials
| Trial | Lowest dose | Highest dose | Placebo |
|---|---|---|---|
| TRIUMPH-1 (general obesity) | 3.0% (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?
Not now. Not soon. Here is the honest timeline.
Retatrutide now has three successful Phase 3 trials. But the Phase 3 program is not finished. Several more trials are still running, and Lilly needs those results before filing with the FDA.
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
- 2026 (ongoing): Remaining Phase 3 readouts expected, including trials for obstructive sleep apnea, cardiovascular outcomes, and liver disease
- As of July 2026: No NDA has been filed with the FDA — retatrutide remains in Phase 3. Lilly has not announced a specific filing date
- Earliest possible approval: 2027 at the soonest, assuming a timely filing — this is speculative
The FDA review process itself typically takes 6 to 10 months after a filing. Do not make medical decisions based on an assumed approval date.
What to watch next in 2026
A few things that could change the picture:
- Remaining Phase 3 trials — Additional readouts for cardiovascular outcomes and liver disease are expected later in 2026.
- FDA filing timeline — Watch for any announcement from Lilly about when they plan to submit. As of July 2026, no NDA has been filed. That announcement will lock in the earliest possible approval date.
- CagriSema FDA decision — Novo Nordisk's NDA is under review, with a decision expected Q4 2026. If approved, it becomes another competitor in the next-generation GLP space.
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 strong Phase 3 results in three different patient populations. It does not have an approved brand name yet, and it should not be discussed like it is already just another routine retail GLP medication. The earliest it could reach patients is 2027.
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- GLP-1 starter guide book — Understand current options while new drugs develop
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Bottom line
Retatrutide matters because it may represent the next wave of obesity and metabolic drugs. The Phase 3 data now includes three positive trials, and the weight loss numbers are the highest seen in this drug class to date. But right now, the honest way to think about it is:
- it is real
- it is important
- it is in Phase 3 clinical trials (as of July 2026), with full ADA 2026 data now published for TRIUMPH-1 and TRANSCEND-T2D-1
- the trial results are strong — up to 28.3% weight loss in general obesity (TRIUMPH-1), 28.7% in obesity with knee osteoarthritis (TRIUMPH-4)
- a subset of patients lost 30.3% of their body weight over 2 years
- it does not have an approved brand name yet
- the earliest possible approval is likely 2027
- do not make medical decisions based on an assumed timeline
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.
