Retatrutide Results: What the Phase 3 Trials Actually Delivered
Quick answer: In TRIUMPH-1, participants on the 12 mg dose lost an average of 70.3 lbs — 28.3% of body weight — over 80 weeks. Nearly two-thirds reached a BMI under 30. In a 104-week extension, retatrutide results reached 85.0 lbs (30.3%), and critically, weight loss had not plateaued. Waist circumference fell 24.1 cm, triglycerides 41.0%, and systolic blood pressure 12.3 mmHg. Retatrutide remains investigational and is not FDA-approved.
TRIUMPH-1: The Headline Numbers
How the triple-agonist mechanism works explains why these numbers exceed what single and dual agonists produce. TRIUMPH-1 randomised 2,339 adults with obesity or overweight plus at least one weight-related comorbidity — hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease — but without type 2 diabetes. Average starting weight was 248.5 lbs (112.7 kg) with an average waist of 46.6 inches.
| 4 mg | 9 mg | 12 mg | Placebo | |
|---|---|---|---|---|
| Weight loss at 80 weeks | 19.0% | 25.9% | 28.3% | 2.2% |
| Average pounds lost | 47.2 lbs | — | 70.3 lbs | — |
| Waist reduction | 16.3 cm (6.4 in) | 21.8 cm (8.6 in) | 24.1 cm (9.5 in) | 3.6 cm (1.4 in) |
The 4 mg result deserves attention that it rarely gets. It required only a single dose-escalation step, produced 47.2 lbs of weight loss, and had a discontinuation rate of 4.1% — below the 4.9% placebo rate. That combination of tolerability and effect is unusual in this drug class — the complete safety and tolerability data covers it by dose.
How Many People Hit Each Threshold
Average weight loss hides the distribution. Responder rates — the proportion of participants reaching a specific threshold — tell you far more about what an individual might expect.
| Weight loss achieved | 4 mg | 9 mg | 12 mg | Placebo |
|---|---|---|---|---|
| ≥25% of body weight | 27.8% | 52.9% | 62.5% | 2.2% |
| ≥30% of body weight | 15.3% | 37.9% | 45.3% | 0.5% |
| ≥35% of body weight | 5.9% | 20.8% | 27.2% | 0.3% |
Percentage of participants achieving each level at 80 weeks (n=2,339)
Source: Eli Lilly TRIUMPH-1, full data presented at the ADA 86th Scientific Sessions, June 2026. Retatrutide is investigational and not FDA-approved.
At 12 mg, more than one in four participants lost at least 35% of their body weight. For context, that is a range historically associated with bariatric surgery rather than medication.
The BMI outcomes make the same point differently: 65.3% of participants on 12 mg finished the trial with a BMI below 30 — no longer meeting the clinical definition of obesity. Among those who started with class 3 obesity (BMI of 40 or above), 37.5% still reached that threshold.
The pattern across those thresholds tracks the dose closely — the dose-by-dose escalation schedule sets out what each arm received.
Did the Weight Loss Plateau? The 104-Week Extension
This is the most consequential finding in the dataset, and the one most coverage skips.
Every weight-loss drug eventually reaches a point where the curve flattens. For semaglutide and tirzepatide, that inflection generally arrives somewhere between 60 and 72 weeks. TRIUMPH-1’s extension tested whether retatrutide behaves the same way.
A prespecified blinded extension enrolled 532 participants with a baseline BMI of 35 or higher who had completed the 80-week study and tolerated their assigned dose. They continued to a maximum tolerated dose of 9 or 12 mg out to 104 weeks. Average starting weight in this group was heavier — 268.3 lbs, BMI 42.8.
| Original dose group | Weight loss at 104 weeks | Pounds lost |
|---|---|---|
| 4 mg → max tolerated | 27.9% | 73.3 lbs |
| 9 mg → max tolerated | 29.5% | 80.7 lbs |
| 12 mg → max tolerated | 30.3% | 85.0 lbs |
Extension cohort: 532 participants with baseline BMI ≥35, escalated to maximum tolerated dose
Source: Eli Lilly TRIUMPH-1 prespecified blinded extension, presented ADA 86th Scientific Sessions, June 2026. Trajectory between measured points is illustrative. Retatrutide is investigational.
Weight was still falling at week 104. There was no plateau in this cohort — which is the strongest available signal that retatrutide’s effect may be more durable than the approved alternatives.
Two caveats keep this honest. This cohort was selected: 532 participants out of 2,339, all with BMI ≥35, all of whom had already tolerated the drug for 80 weeks. That selection favours a good result. And participants were escalated to maximum tolerated dose during the extension, so the 4 mg group’s 27.9% does not represent 4 mg maintained — it represents people who started at 4 mg and moved up.
The 30.3% figure is frequently quoted as retatrutide’s headline number. It belongs to this extension cohort, not the full trial.
Results Beyond the Scale
Weight is the endpoint that gets reported. The cardiometabolic changes are arguably more clinically meaningful.
| Measure | TRIUMPH-1 (80 weeks) | TRANSCEND-T2D-1 (40 weeks) |
|---|---|---|
| Triglycerides | −41.0% | −39.6% |
| Non-HDL cholesterol | −24.2% | −19.8% |
| Systolic blood pressure | −12.3 mmHg | −6.4 mmHg |
| Waist circumference | −24.1 cm | −12.4 cm |
A 12.3 mmHg reduction in systolic blood pressure is substantial — comparable to what a dedicated antihypertensive achieves. High-sensitivity C-reactive protein, a marker of systemic inflammation, also improved.
These are the outcomes that determine whether a weight-loss drug reduces actual disease risk rather than only body mass. TRIUMPH-3, the dedicated cardiovascular outcomes trial, has not yet reported, so hard event data — heart attacks, strokes, deaths — is still outstanding.
Results in Type 2 Diabetes
TRANSCEND-T2D-1 studied 537 adults with type 2 diabetes inadequately controlled by diet and exercise, over 40 weeks.
- HbA1c reduction: 1.69 points at 4 mg, 1.86 at 9 mg, 1.94 at 12 mg, against 0.81 on placebo
- Weight loss: up to 16.8%
Weight loss is consistently lower in diabetes populations than in non-diabetic ones across this entire drug class, so the gap between 16.8% and 28.3% reflects population rather than a weaker effect. One limitation the authors raise themselves: the trial population was largely medication-naïve, which restricts how far the results generalise to people already on other diabetes drugs or insulin.
Results in Cardiovascular Disease and Diabetes: TRIUMPH-2 and TRIUMPH-3
Eli Lilly reported both trials on 23 July 2026.
TRIUMPH-3 enrolled 1,949 adults with severe obesity (BMI 35 or above) and established cardiovascular disease. At 80 weeks the 12 mg dose produced 55.8 lbs of weight loss — 22.6% of body weight — against 7.7 lbs on placebo, with the 9 mg dose at 21.6%. Triglycerides fell 37.0% and non-HDL cholesterol 16.5%.
The cardiovascular endpoints were the more consequential result, and they did not reach significance. MACE-5 produced a hazard ratio of 0.82 (95% CI 0.55–1.22) and MACE-3 a hazard ratio of 1.12 (95% CI 0.64–1.96). Event rates were low, which widens those intervals, and the dedicated TRIUMPH-Outcomes trial has not reported. This is an absence of proof rather than proof of absence — but it means retatrutide has not yet demonstrated the cardiovascular benefit that semaglutide established in SELECT.
TRIUMPH-2, in adults with obesity and type 2 diabetes, met its primary endpoint with improvements in both weight and HbA1c.
Weight loss in both trials came in below TRIUMPH-1’s 28.3%, which is expected: diabetes populations lose less across this entire drug class, and TRIUMPH-3 enrolled patients with established cardiovascular disease.
Results in Knee Osteoarthritis and Sleep Apnoea
TRIUMPH-4 studied adults with obesity and knee osteoarthritis, reporting 28.7% average weight loss at 68 weeks alongside measurable reductions in knee pain.
A sleep apnoea substudy nested within TRIUMPH-1 found a 60.6% reduction in the apnoea-hypopnoea index, from a severe baseline of 58.6 events per hour. That is a large effect in a population where the condition is often treated with a CPAP machine rather than medication.
What Retatrutide Results Look Like in Practical Terms
Translating trial averages into something concrete: the typical TRIUMPH-1 participant started at 248.5 lbs with a 46.6-inch waist. On the 12 mg dose over 80 weeks, they finished roughly 70 lbs lighter with a waist 9.5 inches smaller. In the extension group — heavier at baseline, 268.3 lbs — the average was 85 lbs lost over two years.
Individual results varied widely. Some participants lost more than 35%; others discontinued during dose escalation. Averages describe a distribution, not a promise, and every participant was medically screened and monitored throughout.
How These Results Compare to Approved Drugs
| Retatrutide | Tirzepatide | Semaglutide | |
|---|---|---|---|
| Pivotal trial weight loss | 28.3% at 80 wks | 22.5% at 72 wks | 14.9% at 68 wks |
| Longest reported | 30.3% at 104 wks | 22.9% at 176 wks | — |
| Receptor targets | Three | Two | One |
| FDA status | Investigational | Approved | Approved |
These come from separate trials with different durations, populations, and reporting conventions, so the gaps are indicative rather than measured. TRIUMPH-5, the head-to-head trial against tirzepatide, completes in December 2026 with results expected in 2027 — the full head-to-head comparison covers what it is designed to settle.
Weight loss is only one axis. On proven cardiovascular outcomes the ranking reverses, which matters for anyone with existing heart disease — see how it compares against semaglutide and tirzepatide together.
For safety data, dosing schedules, and regulatory tracking, browse every retatrutide article.
Frequently Asked Questions
How much weight did people lose on retatrutide?
An average of 70.3 lbs (28.3%) at 12 mg over 80 weeks in TRIUMPH-1, and 47.2 lbs (19.0%) at 4 mg. In the 104-week extension, participants with BMI ≥35 averaged 85.0 lbs (30.3%).
Did weight loss stop or plateau?
No. In the 104-week extension, participants continued losing weight between weeks 80 and 104 with no observed plateau — the strongest durability signal in the dataset, though it comes from a selected subgroup.
What percentage of people lost 30% of their body weight?
45.3% on the 12 mg dose, 37.9% on 9 mg, and 15.3% on 4 mg, against 0.5% on placebo.
Do retatrutide results include health improvements beyond weight?
Yes. TRIUMPH-1 recorded a 41.0% reduction in triglycerides, 24.2% in non-HDL cholesterol, 12.3 mmHg in systolic blood pressure, and improvements in hs-CRP. Cardiovascular event data awaits TRIUMPH-3.
Are retatrutide results better than Zepbound?
On current trial data, yes — 28.3% versus 22.5% at each drug’s highest dose. But these are separate trials with different designs. TRIUMPH-5 is the direct comparison, reporting in 2027.
How long did it take to see results?
Weight loss began during dose escalation and continued throughout. Trials ran 68 to 104 weeks, and the extension data suggests the effect had not finished accumulating by two years.
Can I get these results myself?
Retatrutide is not approved and cannot be prescribed. All results here come from clinical trials with screened, monitored participants. Approved alternatives with substantial efficacy data are available today. For where the filing stands, see the full trial and filing status.
Sources
- Eli Lilly. “Lilly’s triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial.” May 21, 2026.
- Eli Lilly. TRIUMPH-1 full data presented at the ADA 86th Scientific Sessions, June 6, 2026.
- Bajaj HS, et al. “Efficacy and safety of retatrutide in people with type 2 diabetes (TRANSCEND-T2D-1).” The Lancet. 2026.
- Jastreboff AM, et al. “Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial.” N Engl J Med. 2023;389:514–526.
- Eli Lilly. TRIUMPH-2 and TRIUMPH-3 topline results, 23 July 2026.
- Eli Lilly. TRIUMPH-4 topline results, December 2025.
- ClinicalTrials.gov: TRIUMPH-1 (NCT05929066), TRIUMPH-5 (NCT06662383), TRANSCEND-T2D-1 (NCT06354660).