Retatrutide Weight Loss Calculator
Retatrutide weight loss calculator: turn Phase 2 and 3 trial averages into pounds or kilograms at your start weight, with caveats for diabetes and dropouts.
What the trial average would mean at your start weight
Based on the 12 mg, 68 weeks (TRIUMPH-4) average of 28.7%. A trial average, not a prediction for any one person. Results vary with dose, adherence and starting weight.
The retatrutide weight loss calculator above turns a trial average into pounds or kilograms at your starting weight. In TRIUMPH-1, the 12 mg group lost an average of 28.3% of body weight over 80 weeks, which is about 62 lb at 220 lb, ending near 158 lb. That assumes everyone stayed on treatment. Counting everyone randomized, the average was 25.0%, and in people with type 2 diabetes it was lower again (20.8% in TRIUMPH-2). As of October 2026 no approved version exists, and nobody can forecast one person's result from a group average.
How the projection works
The calculator multiplies your starting weight by the average percentage lost in the trial you pick. Percentages carry over between units, so 28.3% of 100 kg is 28.3 kg. For scale, the average TRIUMPH-1 participant started at 248.5 lb (112.7 kg), and the 12 mg group lost 70.3 lb (31.9 kg) on average.
The presets cover Phase 2 at 4, 8 and 12 mg, TRIUMPH-1 at 12 mg and TRIUMPH-4 at 12 mg. For a single general number, use TRIUMPH-1: 2,339 adults with obesity or overweight and no diabetes. TRIUMPH-4's 28.7% is the highest preset, but it comes from 445 adults with knee osteoarthritis, 84.0% of whom had a BMI of 35 or higher.
| Start weight | TRIUMPH-1, 12 mg, efficacy (28.3%) | TRIUMPH-1, 12 mg, everyone randomized (25.0%) | TRIUMPH-2, 12 mg, type 2 diabetes (20.8%) |
|---|---|---|---|
| 180 lb | 51 lb | 45 lb | 37 lb |
| 220 lb | 62 lb | 55 lb | 46 lb |
| 260 lb | 74 lb | 65 lb | 54 lb |
Pounds lost at three start weights, rounded to the nearest pound. In kilograms, a 100 kg start works out to about 28 kg, 25 kg and 21 kg across the three columns. The percentages are the trials' averages; the multiplication is ours.
Does the calculator tell you what dose to take?
No. It projects weight, not a dose, so a "GLP-3 dosage calculator for weight loss" (the GLP-3 label people use for retatrutide) is a different tool. The trial results above came from fixed target doses that everyone reached by stepping up from 2 mg every 4 weeks, and the dose question belongs with a prescriber or a trial team. The dosage guide covers the steps the trials used. Looking for a dose calculator instead? The retatrutide dose calculator turns a dose into syringe units, the reconstitution calculator works out the water, and the units page explains the markings.
How the six Phase 3 trials compare
Six Phase 3 trials have reported, from TRIUMPH-4 in December 2025 to TRANSCEND-T2D-2 on October 28, 2026. The 12 mg average ran from 16.8% to 28.7%, and the spread follows who was enrolled and how long they were treated.
Weight lost on 12 mg in each Phase 3 trial
Average % of body weight lost, 12 mg vs the comparator, efficacy estimand (as if everyone stayed on treatment)
The lowest bars belong to the trials in people with type 2 diabetes. TRANSCEND-T2D-2 is the first head-to-head result: on 12 mg, adults with type 2 diabetes lost 20.9% over 80 weeks against 9.4% on Ozempic 2 mg (efficacy estimand, open-label, Lilly's release; no paper yet). The Zepbound, Mounjaro and tirzepatide pages compare retatrutide with approved drugs, and those comparisons come from different trials, people and lengths. TRIUMPH-5, the head-to-head against tirzepatide, hadn't reported as of October 31, 2026.
Same dose, different numbers
The gap between 28.3% and 25.0% is the estimand, a trial's rule for handling people who stopped. The efficacy estimand asks what would have happened had everyone stayed on the drug without other weight treatments. The treatment-regimen estimand keeps everyone who was randomized, including people who quit.
| Trial (weeks) | Estimand | Lower dose | 9 mg | 12 mg | Comparator |
|---|---|---|---|---|---|
| TRIUMPH-1 (80) | Efficacy | 19.0% (4 mg) | 25.9% | 28.3% | 2.2% placebo |
| TRIUMPH-1 (80) | Treatment-regimen | 17.6% (4 mg) | 23.7% | 25.0% | 3.9% placebo |
| TRIUMPH-4 (68) | Efficacy | n/a | 26.4% | 28.7% | 2.1% placebo |
| TRIUMPH-4 (68) | Treatment-regimen | n/a | 20.0% | 23.7% | 4.6% placebo |
| TRIUMPH-3 (80) | Efficacy | n/a | 21.6% | 22.6% | 3.2% placebo |
| TRIUMPH-2 (80) | Efficacy | 12.7% (4 mg) | 19.1% | 20.8% | 4.0% placebo |
| TRIUMPH-2 (80) | Treatment-regimen | 11.9% (4 mg) | 16.8% | 18.8% | 5.1% placebo |
| TRANSCEND-T2D-1 (40) | Efficacy | 11.5% (4 mg) | 15.5% | 16.8% | 2.5% placebo |
| TRANSCEND-T2D-1 (40) | Treatment-regimen | 11.5% (4 mg) | 13.9% | 15.3% | 2.6% placebo |
| TRANSCEND-T2D-2 (80) | Efficacy | n/a | 19.5% | 20.9% | 9.4% Ozempic 2 mg |
TRIUMPH-3 and TRANSCEND-T2D-2 are efficacy-estimand only, because Lilly's releases gave no treatment-regimen figures for them. TRANSCEND-T2D-2 was open-label, and its comparator is Ozempic 2 mg, not placebo.
Our read: if you want a cautious planning figure, use the treatment-regimen number (25.0% for TRIUMPH-1). It's the one the New England Journal of Medicine paper leads with, and it includes people who had to stop. The 28.3% describes people who kept going, which is a real group but not everyone who starts.
Longer follow-up is a separate, smaller dataset. The TRIUMPH-1 extension followed 532 people with a BMI of 35 or higher who finished week 80 on the drug, and the 12 mg group had lost 30.3% at 104 weeks (efficacy estimand) or 29.9% counting everyone in the extension. They started heavier (121.7 kg on average) and were allowed to step to their maximum tolerated dose, so it isn't a result for the whole trial.
What an average does not tell you
Averages hide a spread, and TRIUMPH-1 published how wide it was. At 80 weeks (efficacy estimand), here is the share of people who reached each mark:
| Weight lost | 4 mg | 9 mg | 12 mg | Placebo |
|---|---|---|---|---|
| 25% or more | 27.8% | 52.9% | 62.5% | 2.2% |
| 30% or more | 15.3% | 37.9% | 45.3% | 0.5% |
| 35% or more | 5.9% | 20.8% | 27.2% | 0.3% |
On 12 mg, about 6 in 10 people (62.5%) lost a quarter of their weight, and about 1 in 4 (27.2%) lost 35% or more. The other 4 in 10 lost less than 25%. Starting weight, the dose someone reaches, how long they stay on treatment and how well they tolerate it all move the result. In TRIUMPH-1, 42.4% of the 12 mg group had nausea and 11.3% stopped because of side effects, against 4.9% on placebo; the side effects guide has the rest.
Pace matters too. In the Phase 2 trial the 12 mg group had lost 17.5% by week 24 and 24.2% by week 48, and Lilly's release quoted the lead investigator saying participants hadn't reached a plateau when the study ended. The results timeline follows when the changes showed up in the trials.
Pounds on the scale are total weight. In TRIUMPH-1 the 12 mg group's waist shrank by 24.1 cm (9.5 in) on average from 118.3 cm, which the belly fat page puts in context, and the muscle loss page covers what's known about lean mass. For the full results across trials, see retatrutide results.
Before you plan around a number
The trial results came from a fixed schedule of dose steps run by study teams. If you are weighing retatrutide for sale online, no approved version exists yet, so that structure doesn't come with it. The safety page covers what the trials found.
Lilly last said, on September 29, 2026, that it plans to submit retatrutide to the FDA in the first quarter of 2027 as a Biologics License Application (BLA). On October 2, 2026, the FDA decided that retatrutide is a drug, not a biological product, so an application would need to be filed under section 505 of the Federal Food, Drug, and Cosmetic Act. Lilly's appeal on that question is pending in the Seventh Circuit, and we found no ruling as of October 31, 2026. The FDA approval page tracks it, and the release date page covers what that means for timing.
Frequently asked questions
How much weight could I lose on retatrutide?
Nobody can predict one person's result. In TRIUMPH-1, the 12 mg group lost an average of 28.3% of body weight over 80 weeks if everyone had stayed on treatment, and 25.0% counting everyone randomized. Results spread widely around that: 62.5% of the 12 mg group lost 25% or more, and 27.2% lost 35% or more (efficacy estimand).
Why does the calculator use percentages?
The trials report weight loss as a percentage of starting weight, so the fairest way to translate them is to apply the same percentage to your weight. The same percentage works in pounds and kilograms.
Do lower doses lose less weight?
Yes, in both trials. In TRIUMPH-1 at 80 weeks (efficacy estimand), the average was 19.0% on 4 mg, 25.9% on 9 mg and 28.3% on 12 mg, against 2.2% on placebo. In the Phase 2 trial at 48 weeks it was 8.7% on 1 mg, 17.1% on 4 mg, 22.8% on 8 mg and 24.2% on 12 mg, against 2.1% on placebo.
Do people with type 2 diabetes lose less?
Yes. In TRIUMPH-2, adults with obesity and type 2 diabetes lost an average of 20.8% on 12 mg over 80 weeks (efficacy estimand), and 18.8% counting everyone randomized (The Lancet). The calculator has no diabetes preset, so multiply your weight by that percentage.
Why does TRIUMPH-1 have two numbers, 28.3% and 25.0%?
28.3% is the efficacy estimand: the average if everyone had stayed on the drug and avoided other weight treatments. 25.0% is the treatment-regimen estimand: everyone randomized, whatever they did next. The New England Journal of Medicine paper leads with 25.0%.
How long until I would see that result?
The Phase 3 averages are measured at 40 to 80 weeks, and 12 mg is reached only after four 4-week steps up from 2 mg. Only the Phase 2 trial reported earlier checkpoints: the 12 mg group had lost 17.5% at 24 weeks and 24.2% at 48 weeks (NEJM, 2023). Nobody has published a Phase 3 week-by-week curve we could use.
Is the placebo group included?
The calculator shows retatrutide group averages. The TRIUMPH-1 placebo group lost 2.2% (efficacy estimand) or 3.9% (treatment-regimen), and the Phase 2 placebo group lost 2.1% (Phase 2 NEJM, 48 weeks).
Sources
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial (Jastreboff AM et al.). New England Journal of Medicine, 2023. nejm.org
- Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity (TRIUMPH-1; Jastreboff AM et al.). New England Journal of Medicine, 2026. doi.org
- Phase 2 retatrutide results published in the New England Journal of Medicine: up to 17.5% weight reduction at 24 weeks. Eli Lilly and Company via PR Newswire, 2023. prnewswire.com
- TRIUMPH-1 topline results: retatrutide 12 mg lost an average of 70.3 lbs (28.3%) over 80 weeks. Eli Lilly and Company via PR Newswire, 2026. prnewswire.com
- Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2; Bellido V et al.). The Lancet, 2026. doi.org
- TRIUMPH-2 and TRIUMPH-3 topline results: retatrutide successful in two additional Phase 3 obesity trials. Eli Lilly and Company via PR Newswire, 2026. prnewswire.com
- TRIUMPH-4 topline results: retatrutide 12 mg lost up to an average of 28.7% at 68 weeks. Eli Lilly and Company via PR Newswire, 2025. prnewswire.com
- TRANSCEND-T2D-1 topline results: retatrutide reduced A1C and weight in type 2 diabetes. Eli Lilly and Company via PR Newswire, 2026. prnewswire.com
- TRANSCEND-T2D-2 results: retatrutide delivered greater A1C reduction and more than double the weight loss of Ozempic's highest dose. Eli Lilly and Company via PR Newswire, 2026. prnewswire.com
- Retatrutide delivered substantial weight loss and A1C reduction in obesity and type 2 diabetes (Sep 29, 2026 release with the BLA plan). Eli Lilly and Company via PR Newswire, 2026. prnewswire.com
- FDA letter of Oct 2, 2026 on retatrutide (filed in Eli Lilly and Company v. Kennedy, Seventh Circuit). U.S. Court of Appeals for the Seventh Circuit via CourtListener, 2026. storage.courtlistener.com