Retatrutide Results: Weight Loss Data and What to Expect
Last updated: February 2026
Overview
Retatrutide has produced the largest weight loss results of any obesity drug tested in clinical trials to date. In Phase 3 trials, participants lost an average of 28.7% of their body weight — equivalent to roughly 71 pounds (32 kg) from a starting weight of about 249 pounds (113 kg).
This page consolidates all published weight loss data from retatrutide clinical trials, explains how results varied by dose and population, and provides realistic context for what individual results might look like.
Phase 3 Results: TRIUMPH-4 (December 2025)
TRIUMPH-4 was the first Phase 3 trial to report results. It enrolled 445 adults with obesity (or overweight with complications) and knee osteoarthritis.
| Measure | 9 mg | 12 mg | Placebo |
|---|---|---|---|
| Mean weight loss (completers) | -26.4% | -28.7% | -2.1% |
| Mean weight loss (all randomized) | -21.7% | -23.7% | -1.6% |
| Absolute weight loss | -29.1 kg (64.2 lbs) | -32.3 kg (71.2 lbs) | — |
| Treatment duration | 68 weeks | 68 weeks | 68 weeks |
| Participants | 148 | 148 | 149 |
The "completers" number (28.7%) reflects participants who stayed on treatment for the full 68 weeks. The "all randomized" number (23.7%) includes everyone, even those who stopped treatment early. Both numbers are clinically meaningful.
Source: Eli Lilly press release, December 2025
Phase 2 Results: Obesity Trial (NEJM 2023)
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.
| Dose | Mean Weight Loss at 24 Weeks | Mean Weight Loss at 48 Weeks |
|---|---|---|
| Placebo | -2.1% | -2.1% |
| 1 mg | -6.0% | -8.7% |
| 4 mg (from 2 mg start) | -9.4% | -17.1% |
| 4 mg (from 4 mg start) | -9.0% | -17.5% |
| 8 mg (from 2 mg start) | -16.3% | -22.8% |
| 8 mg (from 4 mg start) | -14.2% | -22.1% |
| 12 mg (from 2 mg start) | -16.7% | -24.2% |
| 12 mg (from 4 mg start) | -15.0% | -22.8% |
A critical observation: weight loss had not plateaued at 48 weeks. Participants were still losing weight when the trial ended. The Phase 3 TRIUMPH-4 trial, which ran for 68 weeks, confirmed this — the 12mg group reached 28.7% weight loss at 68 weeks versus 24.2% at 48 weeks in Phase 2.
Source: Jastreboff et al., NEJM 2023
Phase 2 Results: Type 2 Diabetes Trial (Lancet 2023)
The Phase 2 type 2 diabetes trial enrolled 281 adults with T2D and tested retatrutide over 36 weeks.
| Measure | 12 mg Dose | Placebo |
|---|---|---|
| Weight loss | -16.94% | — |
| HbA1c reduction | -2.02 percentage points | -0.01% |
| Participants reaching HbA1c under 5.7% | 67% | — |
Weight loss was lower in the diabetes population than in the obesity trial — a consistent pattern across all GLP-1 drugs. Patients with type 2 diabetes typically lose less weight on anti-obesity medications, likely because insulin resistance and metabolic dysfunction make fat loss more difficult.
Source: Rosenstock et al., The Lancet 2023
Weight Loss Timeline: When Results Appear
Based on the Phase 2 trial data, here is approximately when weight loss milestones were reached at the 12mg dose:
| Timepoint | Approximate Weight Loss (12 mg) | What's Happening |
|---|---|---|
| Weeks 1-4 | ~1-2% | Starting dose (1 mg), appetite reduction begins |
| Weeks 5-12 | ~4-8% | Dose escalation (2 mg then 4 mg), noticeable weight change |
| Weeks 13-20 | ~10-16% | Dose escalation to 8 mg then 12 mg, rapid weight loss phase |
| Weeks 21-36 | ~16-22% | Maintenance dose, steady weight loss continues |
| Weeks 37-48 | ~22-24% | Weight loss continues but pace begins to slow |
| Weeks 49-68 | ~24-29% | Continued loss (Phase 3 data), approaching plateau |
The timeline shows that retatrutide's weight loss is gradual and cumulative. Most participants did not see dramatic changes in the first month — the major weight loss occurred after reaching the target dose and continuing on it for months.
How Retatrutide Results Compare
| Drug | Trial | Duration | Max Weight Loss |
|---|---|---|---|
| Retatrutide 12 mg | TRIUMPH-4 (Phase 3) | 68 weeks | -28.7% |
| Retatrutide 12 mg | Phase 2 (NEJM) | 48 weeks | -24.2% |
| Tirzepatide 15 mg (Zepbound) | SURMOUNT-1 (Phase 3) | 72 weeks | -22.5% |
| Semaglutide 2.4 mg (Wegovy) | STEP 1 (Phase 3) | 68 weeks | -14.9% |
| CagriSema | Phase 3 | 68 weeks | -22.7% |
| Oral Wegovy 25 mg | OASIS 4 | 68 weeks | ~17% |
Retatrutide's results exceed all currently approved and most investigational obesity drugs. The gap between retatrutide and Wegovy (~14 percentage points) is substantial — roughly the difference between losing 70 pounds versus 37 pounds for a 250-pound starting weight.
Important caveat: these are cross-trial comparisons, not head-to-head data. The patient populations, trial designs, and baseline characteristics differ across studies. No published trial has directly compared retatrutide to tirzepatide or semaglutide.
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. Longer treatment produces more weight loss.
- 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: Participants who discontinue treatment due to side effects obviously achieve less weight loss. 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
While not systematic data, reports from TRIUMPH trial participants provide additional context:
- One TRIUMPH-1 participant reported losing 30.6% of body weight (approximately 75 pounds) after one year on the trial, going from XL/2XL shirts to medium and fitting into size 32 pants for the first time in 20 years
- The same participant reported cholesterol down 30-33%, triglycerides down 70%, blood pressure normalized, fatty liver disease resolved (confirmed by CT scan), and asthma symptoms eliminated
- These individual results are consistent with the upper range of clinical trial outcomes and should not be taken as typical
Beyond Weight Loss: Other Results
TRIUMPH-4 measured outcomes beyond the scale:
Cardiovascular markers
| Marker | Change at 12 mg |
|---|---|
| Systolic blood pressure | -14.0 mmHg |
| Non-HDL cholesterol | Significant reduction (exact % pending full publication) |
| Triglycerides | Significant reduction |
| High-sensitivity CRP (inflammation) | Significant reduction |
Knee osteoarthritis outcomes (TRIUMPH-4 specific)
| Measure | 9 mg | 12 mg | Placebo |
|---|---|---|---|
| WOMAC pain score reduction | 4.5 points (75.8%) | 4.4 points (73.8%) | 2.4 points |
| Completely pain-free | 14.1% | 12.0% | 4.0% |
Liver fat (Phase 2 sub-study)
A sub-study of the Phase 2 trial measured liver fat by MRI and found reductions of up to 82.4% at the highest dose — among the strongest liver fat reduction results for any drug in development. For details, see Retatrutide and Fatty Liver Disease.
Blood sugar control (Phase 2 T2D trial)
In patients with type 2 diabetes, retatrutide reduced HbA1c by 2.02 percentage points, with 67% of participants reaching normoglycemic levels (HbA1c below 5.7%). For details, see Retatrutide for Type 2 Diabetes.
Setting Realistic Expectations
What the averages mean
An average weight loss of 28.7% means that roughly half of participants lost more than this amount and half lost less. The distribution is not symmetrical — a few participants may have lost very little (possibly due to early discontinuation), while many achieved results in the 20-35% range.
The completers vs intention-to-treat gap
TRIUMPH-4 reported two sets of numbers:
- Completers (28.7%): Participants who stayed on treatment for the full 68 weeks
- All randomized (23.7%): Everyone, including those who dropped out
The 5-percentage-point gap reflects the real-world challenge of adherence. Not everyone tolerates the drug well enough to complete the full course. If you stay on treatment, results are significantly better.
Weight loss does not happen overnight
The Phase 2 weight loss curve shows a gradual trajectory. At 24 weeks (6 months), participants on 12mg had lost approximately 16.7% — substantial but less than half the eventual 48-week result. The first 4-8 weeks produce relatively modest changes as the dose titrates up.
No trial has tested maintenance yet
TRIUMPH-6 is studying weight maintenance after initial treatment, but results are not yet available. For all existing GLP-1 drugs, discontinuing treatment leads to significant weight regain. There is no reason to expect retatrutide would be different. Long-term treatment is likely required to maintain results.
Upcoming Results to Watch
Seven Phase 3 readouts are expected in 2026, which will add substantially to the data:
- TRIUMPH-1 and TRIUMPH-2 (obesity): The flagship obesity trials, likely with larger sample sizes and potentially longer treatment periods
- TRIUMPH-3 (type 2 diabetes): Will provide definitive T2D data
- TRIUMPH-MASLD (liver disease): Dedicated liver fat reduction trial
- Additional TRIUMPH trials: Sleep apnea, cardiovascular outcomes, chronic low back pain
For trial-by-trial tracking, see Clinical Trials & Results.
Frequently Asked Questions
How much weight can you lose on retatrutide?
In the Phase 3 TRIUMPH-4 trial, participants who completed 68 weeks of treatment lost an average of 28.7% of their body weight at the 12mg dose — equivalent to about 71 pounds (32 kg) from a starting weight of 249 pounds (113 kg). Individual results ranged widely. At the 9mg dose, average weight loss was 26.4%.
How long does it take to see results on retatrutide?
Based on Phase 2 trial data, noticeable weight loss typically begins within the first 4-8 weeks as the dose is titrated up. By 24 weeks (6 months), participants on the 12mg dose had lost approximately 16.7% of body weight. Weight loss continued through week 48 and beyond, with Phase 3 data showing continued loss through 68 weeks.
Is retatrutide better than Ozempic or Mounjaro for weight loss?
Retatrutide has produced larger average weight loss in clinical trials than both semaglutide (Ozempic/Wegovy, ~15-17%) and tirzepatide (Mounjaro/Zepbound, ~21-23%). However, no head-to-head trial has directly compared these drugs. Retatrutide is also still investigational and not yet available by prescription. For a detailed comparison, see Retatrutide vs Mounjaro vs Ozempic.
What do retatrutide before and after results look like?
Clinical trials measure weight loss as a percentage of starting body weight. For a 250-pound starting weight, the average results at 12mg would be approximately: -22 pounds at 12 weeks, -42 pounds at 24 weeks, -60 pounds at 48 weeks, and -72 pounds at 68 weeks. Individual variation is significant — some participants lost more than 30% of their body weight. No published trial has released individual before-and-after photographs.
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. When or whether weight loss fully plateaus with continued treatment is not yet established.
What happens when you stop taking retatrutide?
No published data addresses weight regain after retatrutide discontinuation. However, all GLP-1 class drugs (semaglutide, tirzepatide) show significant weight regain after stopping treatment. The TRIUMPH-6 trial is studying weight maintenance, but results are not yet available.
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. (2025). Lilly's retatrutide achieved significant weight loss and pain relief in adults with obesity and knee osteoarthritis. Press release.
- Harris, E. (2023). Triple-Hormone Combination Retatrutide Induces 24% Body Weight Loss. JAMA. DOI: 10.1001/jama.2023.12055.
- ClinicalTrials.gov: NCT04881760 (Phase 2, Obesity), NCT04867785 (Phase 2, T2D)
Medical Disclaimer
The content on glp3.wiki is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Retatrutide is an investigational drug that has not been approved by the U.S. Food and Drug Administration (FDA) or any other regulatory agency.
The weight loss results on this page come from clinical trials conducted under controlled conditions with medical supervision. Individual results will vary. Do not use this information to make decisions about your health without consulting a qualified healthcare provider.
Do not attempt to obtain or self-administer retatrutide outside of an approved clinical trial. For information on approved weight loss medications, talk to your doctor.
This site is not affiliated with Eli Lilly and Company or any pharmaceutical manufacturer.
Sources
- Phase 2 trial (NEJM)
New England Journal of Medicine
- TRIUMPH-4 results
Eli Lilly Investor Relations
- JAMA coverage of Phase 2 results
JAMA
Related reading
Retatrutide Clinical Trials & Results
Living tracker of all retatrutide trials — Phase 1 through the TRIUMPH Phase 3 program.
Retatrutide Dosage & Dosing Guide
How retatrutide is dosed in clinical trials — titration schedule, dose levels, and what each dose achieved.
What Is Retatrutide (GLP-3)?
The world's first triple agonist weight loss drug — how it works, what the trials show, and why people call it GLP-3.