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Retatrutide Results and Review: The Weight Loss Data by Dose

Retatrutide Results: Weight Loss Data by Dose

Last updated: September 8, 2026

What do the dose-by-dose numbers show?

Retatrutide has produced substantial average weight loss in Phase 2 and Phase 3 trials. In TRIUMPH-1 — the pivotal Phase 3 obesity trial, which reported topline results on May 21, 2026 — participants on the highest dose lost an average of 28.3% of their body weight (70.3 lbs) at 80 weeks Evidence: Phase 3 RCT, against 2.2% on placebo.
TRIUMPH-4, a smaller Phase 3 trial in adults with obesity and knee osteoarthritis, was the first Phase 3 readout and reported 28.7% under the efficacy estimand at 68 weeks. Both numbers are below.

This page summarizes major reported weight loss results from retatrutide clinical trials, explains how results varied by dose and population, and provides realistic context for what individual results might look like.

Evidence strength — how solid the data behind each labelled claim is, strongest to weakest: Evidence: Phase 3 RCTEvidence: Phase 2Evidence: Phase 1 PKEvidence: PreclinicalEvidence: Community-reportedEvidence: Estimate

TRIUMPH-1 — weight loss by dose?

TRIUMPH-1 is the pivotal Phase 3 obesity trial in Lilly’s obesity development program. It randomized 2,339 participants over 80 weeks, with a 104-week extension in 532 participants with a BMI of 35 or higher.
DoseMean weight loss at 80 weeksAbsolute weight loss
Placebo-2.2%-5.5 lbs
4 mg-19.0%-47.2 lbs
9 mg-25.9%-64.4 lbs
12 mg-28.3%-70.3 lbs

Two further results from the same readout:

  • 45.3% of participants on the 12 mg dose achieved 30% or more weight loss.
  • In the 104-week extension (participants with BMI 35 or higher), the 12 mg group lost 30.3% (85.0 lbs). This is a different subgroup from the 80-week population, not a continuation of the same average — but it is the longest retatrutide exposure reported so far.
ClinicalTrials.gov lists TRIUMPH-1 (NCT05929066) as completed, with primary completion on April 6, 2026. Additional results were presented at the 86th annual American Diabetes Association Scientific Sessions.

The weight-loss table uses Lilly’s efficacy estimand, which estimates the effect assuming participants remained on assigned treatment. It is not a simple average of completers. Lilly reports 2,339 randomized participants; the current registry lists 2,335. This page retains the release’s denominator alongside that discrepancy.

Source: Eli Lilly press release, May 21, 2026

TRIUMPH-4 — weight loss by dose?

TRIUMPH-4 was the first Phase 3 trial to report results. It enrolled 445 adults with obesity (or overweight with complications) and knee osteoarthritis.

Swipe sideways to see every column.

Measure9 mg12 mgPlacebo
Mean weight loss (efficacy estimand)-26.4%-28.7%-2.1%
Mean weight loss (treatment-regimen estimand)-20.0%-23.7%-4.6%
Absolute weight loss-29.1 kg (64.2 lbs)-32.3 kg (71.2 lbs)—
Treatment duration68 weeks68 weeks68 weeks
Participants148148149

The efficacy estimand estimates the treatment effect assuming participants remained on assigned treatment. The treatment-regimen estimand evaluates the effect regardless of adherence. Neither label should be replaced with a simple “completers” average. At 12 mg, the two estimates were 28.7% and 23.7%.

Source: Eli Lilly press release, December 2025

TRIUMPH-2 and TRIUMPH-3 — by population?

Lilly reported topline results from two additional Phase 3 trials on July 23, 2026. TRIUMPH-2 studied adults with obesity or overweight and type 2 diabetes; TRIUMPH-3 studied adults with severe obesity and established cardiovascular disease. Both trials met their primary weight-loss endpoint, but Lilly said detailed results would be presented at future medical meetings and published in peer-reviewed journals.

TRIUMPH-2: Obesity with type 2 diabetes

TRIUMPH-2 randomized 1,152 participants for 80 weeks. The trial studied 4 mg, 9 mg, and 12 mg retatrutide against placebo.
DoseMean weight loss at 80 weeksA1C change at 80 weeks
Placebo-4.0%-0.2%
4 mg-12.7%-1.4%
9 mg-19.1%-1.6%
12 mg-20.8%-1.5%
The TRIUMPH-2 and TRIUMPH-3 tables use the efficacy estimand. The 12 mg TRIUMPH-2 group lost an average of 49.6 pounds. The 9 mg arm had the largest A1C reduction in the release's table, so the glycemic and weight-loss results did not follow exactly the same dose pattern.

TRIUMPH-3: Obesity with established cardiovascular disease

TRIUMPH-3 randomized 1,949 participants for 80 weeks. It studied 9 mg and 12 mg retatrutide against placebo in adults with severe obesity and established cardiovascular disease.
DoseMean weight loss at 80 weeksAbsolute weight loss
Placebo-3.2%-7.7 lbs
9 mg-21.6%-52.7 lbs
12 mg-22.6%-55.8 lbs
At the highest dose, Lilly reported average reductions of 37.0% in triglycerides, 16.5% in non-HDL cholesterol, 9.3 mmHg in systolic blood pressure, 7.5 inches in waist circumference, and 51.2% in hsCRP. These are cardiometabolic risk-factor results from a population that already had cardiovascular disease, not evidence that retatrutide prevents cardiovascular events.
ClinicalTrials.gov now lists both studies as Completed, with actual enrollment of 1,152 for TRIUMPH-2 and 1,946 for TRIUMPH-3; the registry records do not yet contain posted results. The topline release reported hazard ratios for cardiovascular event composites, but the separate event-driven TRIUMPH-Outcomes trial is the program's cardiovascular and kidney outcomes study.
Sources: Eli Lilly, July 23, 2026; ClinicalTrials.gov v2 — NCT05929079; ClinicalTrials.gov v2 — NCT05882045; ClinicalTrials.gov v2 — NCT06383390

Phase 2 obesity — weight loss by dose?

The Phase 2 obesity trial enrolled 338 adults without diabetes and tested multiple dose levels over 48 weeks. This trial provided the first detailed dose-response data for retatrutide.

DoseMean Weight Loss at 24 WeeksMean Weight Loss at 48 Weeks
Placebo-1.6%-2.1%
1 mg-7.2%-8.7%
4 mg (from 2 mg start)-11.8%-16.3%
4 mg (from 4 mg start)-13.9%-17.8%
8 mg (from 2 mg start)-16.7%-21.7%
8 mg (from 4 mg start)-17.9%-23.9%
12 mg (from 2 mg start)-17.5%-24.2%

These are least-squares mean changes for the individual randomized groups. The often-quoted combined results at week 48 were 17.1% for 4 mg and 22.8% for 8 mg, pooling their two starting-dose groups.

Weight loss had not plateaued at 48 weeks. Later Phase 3 studies followed different populations for longer; their averages are not a continuation of this trial’s curve.

Source: Jastreboff et al., NEJM 2023

Phase 2 diabetes — weight loss by dose?

The Phase 2 type 2 diabetes trial enrolled 281 adults with T2D and tested retatrutide over 36 weeks.

Measure12 mgPlacebo
Weight change at 36 weeks-16.94%-3.00%
HbA1c change at 24 weeks-2.02 percentage points-0.01 percentage points

Weight loss and HbA1c were assessed at different timepoints. This diabetes trial should not be treated as the same population as the obesity trial without diabetes.

Phase 3 evidence is now available too: in TRANSCEND-T2D-1, 537 adults with type 2 diabetes treated with diet and exercise were randomized for 40 weeks. The published treatment-regimen results at 12 mg were a 1.94-percentage-point HbA1c reduction and 15.3% weight loss, versus 0.81 points and 2.6% with placebo. See TRANSCEND-T2D-1 for the dose table and analysis distinctions.
Sources: Rosenstock et al., The Lancet 2023; TRANSCEND-T2D-1, The Lancet 2026.

When does weight loss show up?

The clearest reported Phase 2 checkpoints at 12 mg are 17.5% average weight loss at 24 weeks and 24.2% at 48 weeks. These are group results after protocol-directed escalation, not predictions for a particular week or person.
TRIUMPH-1 reported 28.3% at 80 weeks and 30.3% at 104 weeks in its BMI-35-and-above extension subgroup. The extension is a different analysis population. Joining these averages into a personal “before and after” timeline would be misleading.

How do the numbers compare to other drugs?

The retatrutide studies above were placebo-controlled; they do not establish superiority over semaglutide or tirzepatide. Differences in dose, diabetes status, follow-up and statistical analysis matter. A larger percentage from a separate trial is not a head-to-head treatment effect.

TRIUMPH-5 is designed to compare retatrutide with tirzepatide. Until a direct comparison reports, use Retatrutide vs Mounjaro vs Ozempic for the trial distinctions rather than treating these figures as a ranking.

What Individual Results Look Like

Clinical trial averages are useful but do not tell the full story. Individual results vary significantly.

The range of outcomes

In the Phase 2 trial at the 12mg dose:

  • Some participants lost more than 30% of their body weight
  • The average was 24.2% at 48 weeks
  • A small number of participants lost less than 10%
  • Placebo group averaged 2.1% weight loss

Factors that influence individual results

Based on GLP-1 drug class data and the retatrutide trials specifically:

  • Dose: Higher doses produce greater average weight loss. The difference between 4mg (-17%) and 12mg (-24%) in Phase 2 was significant.
  • Treatment duration: Weight loss was still increasing at 48 weeks in Phase 2 and at 68 weeks in Phase 3. These observations do not guarantee continuing loss indefinitely.
  • Starting weight and metabolic health: Participants with type 2 diabetes lost less weight (-16.9% at 12mg) than those without diabetes (-24.2%).
  • Adherence and tolerability: Discontinuation affects how treatment results are interpreted. In TRIUMPH-4, 18.2% of the 12mg group discontinued due to adverse events.
  • Lifestyle factors: All clinical trials included lifestyle counseling (reduced calorie diet and increased physical activity). The extent to which individual participants followed this guidance varied.

Trial participant reports

Participant accounts can explain what people want to know about appetite, progress and daily life, but they cannot verify treatment assignment or predict a typical result. This page uses trial outcomes for numerical expectations. Unlinked before-and-after stories are not a substitute for those data.

What else changed besides weight?

TRIUMPH-4 measured outcomes beyond the scale:

Cardiovascular markers

MarkerChange at 12 mg
Systolic blood pressure-14.0 mmHg
Non-HDL cholesterolSignificant reduction (exact % pending full publication)
TriglyceridesSignificant reduction
High-sensitivity CRP (inflammation)Significant reduction

Knee osteoarthritis outcomes (TRIUMPH-4 specific)

Swipe sideways to see every column.

Measure9 mg12 mgPlacebo
WOMAC pain score reduction4.5 points (75.8%)4.4 points (74.3%)2.4 points
Completely pain-free (post-hoc analysis)14.1%12.0%4.2%

Liver fat (Phase 2 sub-study)

A sub-study of the Phase 2 trial measured liver fat by MRI and found a mean relative liver-fat reduction of 82.4% at 24 weeks in the 12 mg group. This MRI finding is not evidence of fibrosis reversal or a cure for liver disease. For details, see Retatrutide and Fatty Liver Disease.

Blood sugar control (Phase 2 T2D trial)

In the Phase 2 type 2 diabetes trial, the 12 mg group’s mean HbA1c fell by 2.02 percentage points at 24 weeks. For the Phase 2 and current Phase 3 evidence, see Retatrutide for Type 2 Diabetes.

What should you expect?

What the averages mean

A mean is not a median: a 28.7% average does not imply that half the participants lost more and half lost less. It is a group estimate under a specified analysis, not a personal prediction. Scale weight also does not tell you how much change was fat versus lean tissue.

The completers vs intention-to-treat gap

TRIUMPH-4’s 12 mg result was 28.7% under the efficacy estimand and 23.7% under the treatment-regimen estimand. The former estimates effects assuming assigned treatment continued; the latter includes the effects of treatment discontinuation. Their difference is not a guarantee of extra weight loss for someone who persists through side effects.

Weight loss does not happen overnight

At 24 weeks, the Phase 2 12 mg group had lost an average of 17.5%, compared with 24.2% at 48 weeks. The paper does not support a precise first-month target for an individual.

Maintenance results are still awaited

TRIUMPH-6 (NCT06859268) includes an 80-week retatrutide lead-in followed by a 36-week randomized phase comparing continued treatment regimens with placebo. Results are needed to quantify retatrutide-specific maintenance and withdrawal outcomes; the weight-loss trials above do not answer that question.

Which readouts are still coming?

Already reported: TRIUMPH-4 (December 2025), TRIUMPH-1 (May 21, 2026) — the pivotal obesity trial, covered above — and TRIUMPH-2 and TRIUMPH-3 (both July 23, 2026):
  • TRIUMPH-2 (obesity in type 2 diabetes, nested sleep-apnea protocol): -20.8% at 12 mg, -19.1% at 9 mg and -12.7% at 4 mg over 80 weeks, versus -4.0% on placebo, with A1C down up to 1.6%. Weight loss runs lower here than in TRIUMPH-1 — expected in a type 2 diabetes population.
  • TRIUMPH-3 (obesity in cardiovascular disease): -22.6% at 12 mg and -21.6% at 9 mg over 80 weeks, versus -3.2% on placebo, in adults with severe obesity and established cardiovascular disease. Full results.

Still to read out:

  • TRIUMPH-5 (head-to-head vs tirzepatide, NCT06662383): Body-weight efficacy comparison in obesity (~800 participants)
  • TRIUMPH-6 (weight maintenance): The trial that will answer what happens after treatment
  • TRIUMPH-Outcomes (CV/renal outcomes, NCT06383390): Long-term CV composite (CV death, non-fatal MI, non-fatal stroke, and heart-failure events) plus kidney endpoints (~10,000 participants; primary completion ~2029)
  • Phase 3 MASLD master protocol (NCT07165028): Multi-agent MASLD program that includes retatrutide (not a dedicated retatrutide-only liver trial)
  • Additional TRIUMPH trials: Chronic low back pain, and the TRANSCEND-T2D type 2 diabetes program
Type 2 diabetes is studied in both TRIUMPH-2 and TRANSCEND-T2D, with different populations and trial objectives. TRIUMPH-3’s defining feature is established cardiovascular disease.
For trial-by-trial tracking, see Clinical Trials & Results.

Frequently Asked Questions

How much weight can you lose on retatrutide?

In TRIUMPH-1 — the pivotal Phase 3 obesity trial, reported May 21, 2026 — participants on the 12 mg dose lost an average of 28.3% of their body weight (70.3 lbs) at 80 weeks, versus 2.2% on placebo. At 9 mg the average was 25.9%, and at 4 mg it was 19.0%. Individual results ranged widely: 45.3% of the 12 mg group lost 30% or more of their body weight.

The earlier Phase 3 TRIUMPH-4 trial, in adults with obesity and knee osteoarthritis, reported 28.7% at 12 mg under the efficacy estimand at 68 weeks.

What did the pivotal Phase 3 obesity trial show?

TRIUMPH-1 randomized 2,339 participants for 80 weeks and reported topline results on May 21, 2026. Mean weight loss was 28.3% at 12 mg (70.3 lbs), 25.9% at 9 mg, and 19.0% at 4 mg, against 2.2% on placebo. 45.3% of the 12 mg group achieved 30% or more weight loss. In a 104-week extension of participants with a BMI of 35 or higher, the 12 mg group lost 30.3% (85.0 lbs) — the longest retatrutide exposure reported so far. ClinicalTrials.gov lists the trial (NCT05929066) as completed.

How long does it take to see results on retatrutide?

The Phase 2 12 mg group’s reported average weight loss was 17.5% at 24 weeks and 24.2% at 48 weeks. The trial does not give a reliable date when a particular person will notice a change.

Is retatrutide better than Ozempic or Mounjaro for weight loss?

Separate trials have reported different weight-loss averages, but they cannot establish which medicine would work better for a particular person. Retatrutide remains investigational. See Retatrutide vs Mounjaro vs Ozempic for the populations and comparison limits.

What do retatrutide before and after results look like?

Trials report group averages and response thresholds, rather than a standard photographic transformation. In TRIUMPH-1, 45.3% of the 12 mg group achieved at least 30% weight loss at 80 weeks under the efficacy estimand. That does not predict an individual’s appearance, body composition or rate of change.

Does the weight loss plateau?

In the Phase 2 trial, weight loss had not fully plateaued at 48 weeks. The Phase 3 TRIUMPH-4 trial showed continued weight loss through 68 weeks, though the rate of loss was beginning to slow. TRIUMPH-1 extended the picture further: 28.3% at 80 weeks at the 12 mg dose, and 30.3% at 104 weeks in the extension group (participants with a BMI of 35 or higher — a different subgroup, so the two figures are not a single continuous curve). When or whether weight loss fully plateaus with continued treatment is not yet established.

What happens when you stop taking retatrutide?

The results summarized here do not quantify retatrutide-specific weight regain after stopping. TRIUMPH-6 is designed to compare continued treatment with switching to placebo after an initial treatment period.

Sources

  • Jastreboff, A.M., et al. (2023). Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine. DOI: 10.1056/NEJMoa2301972
  • Rosenstock, J., et al. (2023). Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-comparator-controlled, parallel-group, phase 2 trial conducted in the USA. The Lancet. DOI: 10.1016/S0140-6736(23)01053-X
  • Eli Lilly and Company. (2026). Lilly's triple agonist retatrutide delivered powerful weight loss in pivotal Phase 3 obesity trial (TRIUMPH-1). May 21, 2026. Press release.
  • Eli Lilly and Company. (2025). Lilly's retatrutide achieved significant weight loss and pain relief in adults with obesity and knee osteoarthritis. Press release.
  • Eli Lilly and Company. (2026). Lilly's triple agonist, retatrutide, successful in two additional Phase 3 obesity trials (TRIUMPH-2 and TRIUMPH-3). July 23, 2026. Press release.
  • ClinicalTrials.gov. NCT05929079, NCT05882045, and NCT06383390 — current Phase 3 records for TRIUMPH-2, TRIUMPH-3, and TRIUMPH-Outcomes.
  • Harris, E. (2023). Triple-Hormone Combination Retatrutide Induces 24% Body Weight Loss. JAMA. DOI: 10.1001/jama.2023.12055.
  • ClinicalTrials.gov: NCT05929066 (TRIUMPH-1, Phase 3, Obesity — completed), NCT04881760 (Phase 2, Obesity), NCT04867785 (Phase 2, T2D)
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Educational information, not medical advice. It reports published research — it doesn’t recommend that you use, obtain, or supply anything.
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Retatrutide and similar peptides are investigational — not approved by the FDA or any regulator. Semaglutide and tirzepatide are prescription-only medicines, available only through a licensed prescriber.
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Do not make decisions about your health without consulting a qualified healthcare provider. For trial enrolment, see ClinicalTrials.gov. More on how we review.

Sources

Grounded in primary sources
NEJMThe LancetJAMAFDAClinicalTrials.gov